1,198 results
Search Results
2. Flexible and Robust Functionalized Boron Nitride/Poly(p-Phenylene Benzobisoxazole) Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation.
- Author
-
Tang, Lin, Ruan, Kunpeng, Liu, Xi, Tang, Yusheng, Zhang, Yali, and Gu, Junwei
- Subjects
THERMAL conductivity ,ELECTRIC insulators & insulation ,ELECTRIC conductivity ,NANOCOMPOSITE materials ,THERMAL stability ,BORON nitride ,THERMAL insulation - Abstract
Highlights: m-BN/PNF nanocomposite paper with nacre-mimetic layered structures prepared via sol–gel film transformation approach presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical property and thermal stability. When the mass fraction of m-BN is 50 wt%, m-BN/PNF nanocomposite paper exhibits excellent thermal conductivity and electrical insulation. The λ
∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1 , and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1 , respectively. The m-BN/PNF nanocomposite paper with 50 wt% m-BN also presents outstanding mechanical properties (tensile strength of 193.6 MPa) and thermal stability (thermal decomposition temperature of 640 °C). With the rapid development of 5G information technology, thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent. In this work, "high-temperature solid-phase & diazonium salt decomposition" method is carried out to prepare benzidine-functionalized boron nitride (m-BN). Subsequently, m-BN/poly(p-phenylene benzobisoxazole) nanofiber (PNF) nanocomposite paper with nacre-mimetic layered structures is prepared via sol–gel film transformation approach. The obtained m-BN/PNF nanocomposite paper with 50 wt% m-BN presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical properties and thermal stability, due to the construction of extensive hydrogen bonds and π–π interactions between m-BN and PNF, and stable nacre-mimetic layered structures. Its λ∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1 , and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1 , respectively. Besides, it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640 °C, showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
3. Microstructure and mechanical properties of multilayer SiC nanofiber paper‐reinforced SiC composites by the NITE method.
- Author
-
Chen, Hao, Chen, Jianjun, Yang, Jiahao, Ahmad, Zahoor, Zhu, Mingming, Xiong, Yilian, Tao, Jiyu, and Li, Jinxia
- Subjects
- *
MICROSTRUCTURE , *FRACTURE toughness , *CERAMIC-matrix composites , *BORON nitride , *NANOFIBERS , *CERAMICS , *SINTERING - Abstract
In this work, stacked SiC fibers paper‐reinforced SiC ceramic matrix composites (SiCnf/SiC CMCs) were prepared by nanoimpregnation and transient eutectic (NITE) process using ultra‐long single‐crystal SiC nanofibers. The effect of the SiCnf surface modification via boron nitride (BN) interphase deposition as well as the sintering additive (Al2O3–Y2O3) content on the density, microstructure, and mechanical properties of SiCnf/SiC CMCs has been investigated systematically. The results revealed that the laminated SiCnf/SiC CMCs feature a significant saw‐tooth‐like curve on the load–displacement test, which indicates that the obtained laminated structure with the weak interlayer binding owning to the BN coating treatment possesses significant toughening to the SiC ceramics. Specifically, the SiCnf/SiC CMCs with the sintering additive content of 12 wt% revealed a fracture toughness of over 10 MPa m1/2 after 60 min of BN interface deposition, which is 104.31% higher than that of the composites prepared without BN coating. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Hydrogen‐Bond‐Mediated Surface Functionalization of Boron Nitride Micro‐Lamellae toward High Thermal Conductive Papers
- Author
-
Shulei Yu, PeiChi Liao, Yilin Zhang, Yifei Li, Huifeng Tian, Ruijie Li, Shizhuo Liu, Zhixin Yao, Zhenjiang Li, Yihan Wang, Lina Yang Zhang, SASAKI U, Junjie Guo, Lifen Wang, Shulin Bai, Ji Chen, Xuedong Bai, and Lei Liu
- Subjects
boron nitride ,flexibility ,hydrogen bonds ,surface functionalization ,thermal conduction ,Physics ,QC1-999 ,Technology - Abstract
Abstract Wide‐bandgap, layered hexagonal boron nitride (h‐BN) possesses excellent electrical insulation and ultrahigh thermal conductivity simultaneously, offering a perfect candidate for the growing demands of heating dissipations in modern chip industries and power electronics. Hybrids of h‐BN with polymers fulfill the thermal management materials (TMMs) requirement of flexibility, while the composite poses severe challenges in the interfacial bonding and excess thermal resistance. To date, the practical bonding between h‐BN intrinsic surfaces and polymer matrices remains elusive. This work reports on the effective alignment of h‐BN micro‐lamellae by introducing nitrogen‐atoms‐containing polymers as inter‐lamellae bridging mediums. Based on theoretical calculations the hydrogen bonding between polymer chains and the BN surface is revealed by differential charge densities mapping. It is shown experimentally that the neuron‐like polymer bundles strongly bonding surfaces of two neighboring h‐BN platelets as direct, microscopic evidence of the structure models. An extra alignment of h‐BN induced by this strong interfacial interaction leads to a higher degree of h‐BN stacking order, boosting the thermal conduction by eight times. These results reveal one unprecedented method to non‐covalently functionalize the h‐BN surface and expand the TMMs family in the dimension of the filler size, paving the way for exploring the larger‐sized ceramic TMMs.
- Published
- 2023
- Full Text
- View/download PDF
5. 2-Dimensional Materials for Performance Enhancement of Surface Plasmon Resonance Biosensor: Review Paper.
- Author
-
Wulandari, Chandra, Septiani, Ni Luh Wulan, Nugraha, Nuruddin, Ahmad, and Yuliarto, Brian
- Subjects
- *
SURFACE plasmon resonance , *BORON nitride , *BIOSENSORS , *MOLECULAR kinetics , *TRANSITION metals , *LIGHT absorption - Abstract
Surface plasmon resonance (SPR)--based biosensors compete and excel among optical biosensors because of exceptional features such as high sensitivity, label-free, and real-time measurement, allowing the observation of molecular binding kinetics. In SPR biosensors and other biosensor techniques, surface functionalization and bioreceptor attachment are effective strategies to improve sensor performance. The application of an appropriate immobilization matrix for the bioreceptor is an essential step in maximizing the absorption of the bioreceptor on the sensor surface, thereby improving a specific target-sensor interaction. Furthermore, the materials should provide excellent optical properties to enhance the response signal. The high surface-to-volume ratio and high optical absorption of 2D materials qualify these requirements, thus promising advancements for SPR biosensors. This article reviews the recent SPR biosensor study with the use of the 2D materials family to improve the sensor performance, including graphene, transition metal dichalcogenides (TMDCs), MXene, black phosphorus (BP), perovskite, and boron nitride (BN). The materials properties and enhancement mechanisms of different 2D materials are discussed comprehensively. This review was expected to provide a future perspective and design approach for 2D materials-based SPR biosensors. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
6. Inkjet-printed low-dimensional materials-based complementary electronic circuits on paper.
- Author
-
Brunetti, Irene, Pimpolari, Lorenzo, Conti, Silvia, Worsley, Robyn, Majee, Subimal, Polyushkin, Dmitry K., Paur, Matthias, Dimaggio, Elisabetta, Pennelli, Giovanni, Iannaccone, Giuseppe, Macucci, Massimo, Pieri, Francesco, Mueller, Thomas, Casiraghi, Cinzia, and Fiori, Gianluca
- Subjects
ELECTRONIC circuits ,ELECTRONIC paper ,DIGITAL electronics ,FLEXIBLE electronics ,LOGIC circuits ,WEARABLE technology ,INK-jet printers ,BORON nitride - Abstract
Complementary electronics has represented the corner stone of the digital era, and silicon technology has enabled this accomplishment. At the dawn of the flexible and wearable electronics age, the seek for new materials enabling the integration of complementary metal-oxide semiconductor (CMOS) technology on flexible substrates, finds in low-dimensional materials (either 1D or 2D) extraordinary candidates. Here, we show that the main building blocks for digital electronics can be obtained by exploiting 2D materials like molybdenum disulfide, hexagonal boron nitride and 1D materials such as carbon nanotubes through the inkjet-printing technique. In particular, we show that the proposed approach enables the fabrication of logic gates and a basic sequential network on a flexible substrate such as paper, with a performance already comparable with mainstream organic technology. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Supply Of Molybdenum Sulphide, Tungsten Sulphide, In Boron Nitride, Gemcitabine Hydrochloride, Micro Spatula, Hydrochloric Acid, Acetone, Milipore Filter Paper
- Subjects
Gemcitabine ,Acetone ,Hydrochloric acid ,Tungsten ,Molybdenum ,Chemical tests and reagents ,Boron nitride ,Business, international - Abstract
Tenders are invited for Supply of Molybdenum Sulphide, Tungsten Sulphide, in Boron Nitride, Gemcitabine Hydrochloride, Micro Spatula, Hydrochloric Acid, Acetone, Milipore Filter Paper Tender Category : Goods Major organization : [...]
- Published
- 2022
8. VANDERBILT ENGINEERS' SCIENCE PAPER REVIEWS SCOPE OF ATOMICALLY THIN MEMBRANES FOR SUBATOMIC SEPARATIONS
- Subjects
Engineers ,Boron nitride ,News, opinion and commentary ,Vanderbilt University - Abstract
NASHVILLE, Tenn. -- The following information was released by Vanderbilt University: A paper by Vanderbilt engineers that explores the scope to scale up the sizes of atomically thin membranes and [...]
- Published
- 2021
9. Massive enhancement in power output of BoPET-paper triboelectric nanogenerator using 2D-hexagonal boron nitride nanosheets
- Author
-
Kuzhichalil Peethambharan Surendran, Harris Varghese, Ainikulangara Sundaran Bhavya, and Achu Chandran
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Open-circuit voltage ,Nanogenerator ,law.invention ,chemistry.chemical_compound ,BoPET ,chemistry ,Boron nitride ,law ,Finger tapping ,Optoelectronics ,General Materials Science ,Electrical and Electronic Engineering ,business ,Short circuit ,Triboelectric effect ,Light-emitting diode - Abstract
In the present era of the Internet of Things (IoT) and sensor networks, clean and sustainable power sources are in huge demand, and triboelectric nanogenerators (TENGs) are a hot cake in green energy production. Here, we have developed a contact-separation mode TENG using liquid-phase exfoliated 2D-hexagonal boron nitride nanosheets (BNNSs) coated on biaxially-oriented polyethylene terephthalate (BoPET) and paper as counter triboelectric materials, which showed an impressive 70 times higher power output than simple BoPET-paper TENG assembly. Even under a moderate finger tapping force (~3 N), the developed BNNSs/BoPET-paper TENG device could generate an open circuit output voltage of ~200 V and a short circuit current density of ∼0.48 mA/m2. While under load testing, the peak value of electric power density for the BNNSs/BoPET-paper TENG device reached ~0.14 W/m2 at 200 MΩ resistive load. The incorporation of BNNSs has significantly enhanced the electron-accepting capabilities of the BoPET film which is evident from the enhanced dielectric permittivity of the BNNSs/BoPET assembly, and thus resulted in the enhanced electrical output of TENG. Additionally, the fabricated BNNSs-TENG was successfully demonstrated for powering electronic gadgets such as LCD clock, digital thermometer, and LEDs through cyclic finger tapping force.
- Published
- 2021
10. High-temperature dielectric paper with high thermal conductivity and mechanical strength by engineering the aramid nanofibers and boron nitride nanotubes
- Author
-
Li-Chuan Jia, Junwen Ren, Wenfu Wei, Xiaolong Huang, Chengmei Wei, Wang Zhong, Zihan Li, Lihua Zhao, and Wenjun Ning
- Subjects
Hydrogen bond ,Dielectric performance ,Materials science ,Mechanical Engineering ,Composite number ,Mechanical properties ,Dielectric ,Aramid ,chemistry.chemical_compound ,Thermal conductivity ,chemistry ,Mechanics of Materials ,Boron nitride ,Nanofiber ,TA401-492 ,General Materials Science ,Dielectric loss ,Thermal stability ,Boron nitride nanotubes ,Composite material ,Materials of engineering and construction. Mechanics of materials ,Aramid nanofibers - Abstract
Aramid paper is ubiquitous in advanced electronics and high-voltage equipment by virtue of their outstanding dielectric properties, mechanical reliability, and thermal stability. However, their limited thermal conductivity still fails to satisfy the stringent demands for heat dissipation in applications with high power and high energy density. Herein, we report a highly thermally conductive composite paper prepared by synergistically combining one-dimensional (1D) aramid nanofibers (ANFs), 1D edge-hydroxylated boron nitride nanotubes (BNNTs), and polyethyleneimine (PEI). The resultant composite paper exhibits high thermal conductivity (9.91 Wm−1K−1), low dielectric loss (
- Published
- 2021
11. Highly thermally conductive flexible insulated PI/BNNS@rGO nanocomposite paper with a three-dimensional network bridge structure.
- Author
-
Yu, Baokang, Zhou, Yuhang, Luo, Zhouai, Fan, Jie, He, Jianxin, Liu, Yong, and Jin, Xuling
- Subjects
- *
POLYIMIDES , *THERMAL interface materials , *NANOCOMPOSITE materials , *NANOFIBERS , *BORON nitride , *THERMAL conductivity , *ELECTRIC insulators & insulation - Abstract
[Display omitted] • Exfoliated BNNS obtained through hydrothermal reaction and in ball milling. • The rGO acts as a bridge connecting the adjacent and stacked BNNS layers, increasing the number of thermal conductivity pathways. • Highly enhanced in-plane TC up to 16.92 W m−1 k−1 with 50 wt% BNNS and 2.5 wt% rGO loading. The sharp increases in power consumption and heating capacity caused by the emergence of intelligent electronic devices necessitate the development of highly thermally conductive thermal interface materials (TIMs) with good heat dissipation properties. Boron nitride nanosheets (BNNS) are ideal materials with high thermal conductivity. Hence, it should be possible to produce flexible high thermal conductivity nanocomposites with a three-dimensional network containing ultrathin, large, and uniformly thick BNNS. In this study, large-scale (1–1.5 µm) fewer-layered (2 nm) BNNS with a high yield of 80% were prepared through the separation of a NaOH–LiCl aqueous solution by a hydrothermal method and in ball milling. Highly thermally conductive insulating nanocomposite paper with a three-dimensional bridging structure of two-component nanosheets filled with nanofibers was fabricated by a simple electrospinning–electrospraying technique. The mechanical properties of the polyimide (PI)/BNNS@reduced graphene oxide nancomposite paper were improved by 168% as compared with those of the PI/BNNS composite. With an increase in the BNNS content, a layered microstructure similar to that of natural nacre was produced, which resulted in a large in-plane thermal conductivity of 16.92 W/m·K. The described method can facilitate the design of TIMs with good electrical insulation properties, thermal stability, and flexibility. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
12. Hydrogen‐Bond‐Mediated Surface Functionalization of Boron Nitride Micro‐Lamellae toward High Thermal Conductive Papers.
- Author
-
Yu, Shulei, Liao, PeiChi, Zhang, Yilin, Li, Yifei, Tian, Huifeng, Li, Ruijie, Liu, Shizhuo, Yao, Zhixin, Li, Zhenjiang, Wang, Yihan, Zhang, Lina Yang, U, SASAKI, Guo, Junjie, Wang, Lifen, Bai, Shulin, Chen, Ji, Bai, Xuedong, and Liu, Lei
- Subjects
ELECTRIC insulators & insulation ,BORON nitride ,INTERFACIAL bonding ,POWER electronics ,THERMAL resistance ,HYDROGEN bonding - Abstract
Wide‐bandgap, layered hexagonal boron nitride (h‐BN) possesses excellent electrical insulation and ultrahigh thermal conductivity simultaneously, offering a perfect candidate for the growing demands of heating dissipations in modern chip industries and power electronics. Hybrids of h‐BN with polymers fulfill the thermal management materials (TMMs) requirement of flexibility, while the composite poses severe challenges in the interfacial bonding and excess thermal resistance. To date, the practical bonding between h‐BN intrinsic surfaces and polymer matrices remains elusive. This work reports on the effective alignment of h‐BN micro‐lamellae by introducing nitrogen‐atoms‐containing polymers as inter‐lamellae bridging mediums. Based on theoretical calculations the hydrogen bonding between polymer chains and the BN surface is revealed by differential charge densities mapping. It is shown experimentally that the neuron‐like polymer bundles strongly bonding surfaces of two neighboring h‐BN platelets as direct, microscopic evidence of the structure models. An extra alignment of h‐BN induced by this strong interfacial interaction leads to a higher degree of h‐BN stacking order, boosting the thermal conduction by eight times. These results reveal one unprecedented method to non‐covalently functionalize the h‐BN surface and expand the TMMs family in the dimension of the filler size, paving the way for exploring the larger‐sized ceramic TMMs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
13. Boron nitride nanosheets: Large-scale exfoliation in NaOH-LiCl solution and their highly thermoconductive insulating nanocomposite paper with PI via electrospinning-electrospraying.
- Author
-
Yu, Baokang, Fan, Jie, He, Jianxin, Liu, Yong, Wang, Rongwu, Qi, Kun, Han, PengJu, and Luo, Zhouai
- Subjects
- *
BORON nitride , *THERMAL insulation , *NANOSTRUCTURED materials , *THERMAL management (Electronic packaging) , *NANOCOMPOSITE materials , *FIBROUS composites , *NANOFIBERS - Abstract
The miniaturisation of electronic components requires high-performance materials with insulating and thermal conductive properties for electronic packaging and thermal management. Boron nitride nanosheets (BNNS) are a desirable thermal conductive filler due to their excellent thermal stability, chemical stability, and high thermoconductivity. However, it remains challenging to mass produce ultra-thin large-scale BNNS and combine them with small amounts of polymers to fabricate malleable thermoconductive composites for flexible electronic devices. Herein, we report a new method to prepare BNNS at high yield by high-temperature oxidation treatment followed by hydrothermal exfoliation in NaOH-LiCl solution. We further fabricated flexible, insulating, and highly thermoconductive BNNS/PI (polyimide) nanocomposite paper, via a scalable layer-by-layer process that involves electrospinning of PI fibres and eletrospraying of BNNS. The prepared BNNS have a transverse size of 1.18 µm and a thickness of 1–2.9 nm, with a high yield of 75.48% at a concentration of 3.38 mg mL− 1. The BNNS/PI nanocomposite paper exhibited an ultrahigh in-plane thermal conductivity (7.58 W m−1 K−1), 2005% higher than that of the pure PI nanofibre composite. This simple method has wide application potential in next-generation electronic devices to design thermal interface materials with excellent electrical insulation, thermostability, and flexibility. [Display omitted] • Exfoliated BNNS obtained through thermal oxidation and hydrothermal reaction. • BNNS were arranged along PI nanofibre direction by electrospraying. • Highly enhanced in-plane TC up to 7.58 W m−1 k−1 with 50 wt% BNNS loading. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
14. Superhydrophobic and thermally conductive carbon black/hexagonal boron nitride@Fe3O4/cellulose composite paper for electromagnetic interference shielding.
- Author
-
Habibi, Navid and Pourjavadi, Ali
- Subjects
- *
ELECTROMAGNETIC shielding , *ELECTROMAGNETIC interference , *CARBON-black , *THERMAL conductivity , *BORON nitride , *ELECTRIC conductivity - Abstract
Herein, a series of superhydrophobic thin polyacrylic resin-coated carbon black (CB)/hexagonal boron nitride (h-BN)@Fe 3 O 4 /cellulose composite papers with good flexibility, low density (~0.67 g/cm3), high electrical conductivity (~0.065 S/cm), good thermal conductivity (0.462 W.m−1. K−1), and with water contact angle (WCA) of 153° were successfully fabricated by a facile dip-coating/spraying method. The CB-BN@Fe 3 O 4 distribution in cellulose matrix provided high electrical conductivity in the in-plane and thickness directions. The electrical conductivity in both in-plane and thickness directions increased by increasing the number of vacuum-assisted dip-coating cycles. Moreover, these composites exhibited excellent electromagnetic interference shielding effectiveness (EMI SE) in the frequency range of 8.2–12.4 GHz. The absorption was the main mechanism for attenuation of EM waves for this composite paper. A multilayer of this composite with 12 wt% filler exhibited a higher EMI SE of 68.2 dB compared to its monolayer composite. The composites showed good thermal stability and excellent stability against washing and 150 times bending tests. Overall, this study proposes that polyacrylic resin-coated CB/BN@Fe 3 O 4 /cellulose papers can be used as wallpaper in buildings such as hospitals and antenna rooms that are exposed to electromagnetic waves. [Display omitted] • Polyacrylic resin coated CB/BN@Fe 3 O 4 /cellulose paper was prepared through a facile dip-coating/spraying method. • This composite paper showed superhydrophobic behavior with WCA of 153° and thermal conductivity of 0.462 W.m−1. K−1. • The EMI SE of this composite reaches as high as 68.2 dB in a multilayer form. • This composite was physically durable after 150 times of bending test and after washing process. • This composite can be used as portable EMI shielding materials or wallpaper in buildings such as hospitals and antenna room. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
15. Boron nitride/carbon nanotube composite paper for self-activated chemiresistive detection.
- Author
-
Lim, Guh-Hwan, Bae, Seonhee, Kim, Yong-Jae, Lee, Kyu Seung, Cho, Hyunjin, Park, Young Jae, Lee, Hong-Soo, Kim, Sung-Hwan, Kim, Sooyeon, Chung, Hee-Suk, Yun, Yong Ju, Kim, Kayoung, Kim, Chulki, Seo, Jong-Su, Moon, Hi Gyu, and Son, Dong Ick
- Subjects
- *
BORON nitride , *CARBON composites , *FINITE element method , *WEARABLE technology , *DETECTION limit - Abstract
Carbon nanotube buckypaper has been considered as one of the promising candidates for chemiresistive sensor applications, especially with environmental monitoring purpose due to large surface area, device flexibility, and the broad spectrum of responsive chemical vapor molecules. However, one of typical drawbacks in carbon-based sensors is incomplete recovery to their initial state after chemical reactions with analytes, degrading sensing reproducibility. In this work, we present a thermally stable and robust boron nitride nanotube/carbon nanotube (BNCNT) hybrid paper for self-enhanced chemiresistive sensing with full reversibility. Boron nitride nanotube (BNNT) plays an essential role in long-term reliability (33 days) at the operating temperature of 200 °C. In addition, a finite-element method was applied to understand the thermal behavior of the BNCNT network structure. The BNCNT paper-based chemiresisitve sensor exhibited highly sensitive, selective, and fully reversible responses to NO 2 without external heating. Also, the sensor demonstrated the detection limit of parts per billion (ppb)-levels under strain with high reliability. With these remarkable strengths, significantly facile and cost-effective fabrication processes provide an environmental sensing platform for use in smart clothing with wearable electronics. • Boron nitride nanotube/carbon nanotube (BNCNT)-based chemiresistive sensor with full reversibility was developed. • The BNCNT paper exhibits a highly sensitive detection to NO 2 at room temperature. • The detection limit (DL) is 3.41 parts per billion (ppb) even under strained conditions with high reliability. • The BNCNT papers maintained its self-enhanced temperature of 200 °C during a long-term stability test for 33 days. • The BNNT plays a major role in the long-term reliability of maintaining a temperature of CNT networks. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
16. Contents list.
- Subjects
COORDINATION polymers ,PHASE transitions ,BORON nitride ,OPEN access publishing ,ENVIRONMENTAL sciences ,MONOMOLECULAR films ,SCIENTIFIC community - Abstract
The document is a contents list for the journal CrystEngComm. It highlights the articles and papers featured in the current issue, including topics such as cobalt coordination polymers, environmental science, polymorphism, and lithium storage. The journal aims to advance the understanding and design of solid-state and crystalline materials. The Royal Society of Chemistry, a leading chemistry community, publishes the journal and reinvests its profits back into the chemistry community. [Extracted from the article]
- Published
- 2024
- Full Text
- View/download PDF
17. High-temperature dielectric paper with high thermal conductivity and mechanical strength by engineering the aramid nanofibers and boron nitride nanotubes.
- Author
-
Zhao, Lihua, Wei, Chengmei, Li, Zihan, Wei, Wenfu, Jia, Lichuan, Huang, Xiaolong, Ning, Wenjun, Wang, Zhong, and Ren, Junwen
- Subjects
- *
BORON nitride , *THERMAL conductivity , *MECHANICAL engineering , *NANOTUBES , *MECHANICAL engineers - Abstract
[Display omitted] • A composite paper was prepared by combining aramid nanofibers, boron nitride nanotubes, and polyethyleneimine. • Elaborating interfacial hydrogen bonds design can optimize the mechanical properties of composite paper. • The composite paper has high thermal conductivity and unique dielectric performance. Aramid paper is ubiquitous in advanced electronics and high-voltage equipment by virtue of their outstanding dielectric properties, mechanical reliability, and thermal stability. However, their limited thermal conductivity still fails to satisfy the stringent demands for heat dissipation in applications with high power and high energy density. Herein, we report a highly thermally conductive composite paper prepared by synergistically combining one-dimensional (1D) aramid nanofibers (ANFs), 1D edge-hydroxylated boron nitride nanotubes (BNNTs), and polyethyleneimine (PEI). The resultant composite paper exhibits high thermal conductivity (9.91 Wm−1K−1), low dielectric loss (<0.01), and ultrahigh electrical breakdown strength (∼334 kV/mm) with an exceptional heat resistance performance. Three-dimensional hydrogen bonding networks were constructed between the ANF framework, PEI, and BNNTs, endowing the composite paper with a superior tensile strength (up to 317 MPa) and Young's modulus (∼7.7 GPa), which are significantly higher than those of the commercial Nomex T410 paper. This research provides important insights into the design and fabrication of multifunctional insulating paper for application in modern integrated electronic and power systems. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
18. Hexagonal Boron Nitride Market size to increase by USD 345.2 million between 2022 to 2027, 3M Co., American Elements, BORTEK Boron Technologies and Mechatronic Inc., and more among key companies, Technavio
- Subjects
3M Co. -- International economic relations ,Brand equity ,Lubrication and lubricants ,Coatings ,Paper products industry -- International economic relations ,Boron nitride ,Motor vehicles -- Equipment and supplies ,Lubricants industry -- International economic relations ,General interest ,News, opinion and commentary - Abstract
NEW YORK: Infiniti Research, Inc. has issued the following news release: The hexagonal boron nitride market size is expected to grow by USD 345.2 million from 2022 to 2027. In [...]
- Published
- 2024
19. Research Progress of Single-Photon Emitters Based on Two-Dimensional Materials.
- Author
-
Zhang, Chengzhi, Gong, Zehuizi, He, Dawei, Yan, Yige, Li, Songze, Zhao, Kun, Wang, Jiarong, Wang, Yongsheng, and Zhang, Xiaoxian
- Subjects
QUANTUM communication ,BORON nitride ,QUANTUM computing ,TRANSITION metals ,SURFACE states ,FIELD emission ,QUANTUM optics - Abstract
From quantum communications to quantum computing, single-photon emitters (SPEs) are essential components of numerous quantum technologies. Two-dimensional (2D) materials have especially been found to be highly attractive for the research into nanoscale light–matter interactions. In particular, localized photonic states at their surfaces have attracted great attention due to their enormous potential applications in quantum optics. Recently, SPEs have been achieved in various 2D materials, while the challenges still remain. This paper reviews the recent research progress on these SPEs based on various 2D materials, such as transition metal dichalcogenides (TMDs), hexagonal boron nitride (hBN), and twisted-angle 2D materials. Additionally, we summarized the strategies to create, position, enhance, and tune the emission wavelength of these emitters by introducing external fields into these 2D system. For example, pronounced enhancement of the SPEs' properties can be achieved by coupling with external fields, such as the plasmonic field, and by locating in optical microcavities. Finally, this paper also discusses current challenges and offers perspectives that could further stimulate scientific research in this field. These emitters, due to their unique physical properties and integration potential, are highly appealing for applications in quantum information and communication, as well as other physical and technological fields. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. DIW-Printed Thermal Management PDMS Composites with 3D Structural Thermal Conductive Network of h-BN Platelets and Al 2 O 3 Nanoparticles.
- Author
-
Zhu, Hongyi, Wu, Shunxia, Tang, Rui, Li, Yang, Chen, Gang, Huang, Bingxue, and Peng, Biyou
- Subjects
ALUMINUM oxide ,THERMAL conductivity ,BLOOD platelets ,SHEARING force ,NANOPARTICLES ,MANUFACTURING processes - Abstract
Electronic devices play an increasingly vital role in modern society, and heat accumulation is a major concern during device development, which causes strong market demand for thermal conductivity materials and components. In this paper, a novel thermal conductive material consisting of polydimethylsiloxane (PDMS) and a binary filler system of h-BN platelets and Al
2 O3 nanoparticles was successfully fabricated using direct ink writing (DIW) 3D printing technology. The addictive manufacturing process not only endows the DIW-printed composites with various geometries but also promotes the construction of a 3D structural thermal conductive network through the shearing force during the printing process. Moreover, the integrity of the thermal conductive network can be optimized by filling the gaps between the BN platelets with Al2 O3 particles. Resultingly, the configuration of the binary fillers is arranged by the shearing force during the DIW process, fabricating the thermal conductive network of oriented fillers. The DIW-printed BN/Al2 O3 /PDMS with 45 wt% thermal conductive binary filler can reach a thermal conductivity of 0.98 W/(m·K), higher than the 0.62 W/(m·K) of the control sample. In this study, a novel strategy for the thermal conductive performance improvement of composites based on DIW technology is successfully verified, paving a new way for thermal management. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
21. Hexagonal boron nitride nanosheets: Fabrication, thermal properties and application in polymers.
- Author
-
Wenchao Zhang, Yuan Liang, Dong Yue, and Yu Feng
- Subjects
THERMAL properties ,NANOSTRUCTURED materials ,POLYMERS ,BORON nitride ,THERMAL conductivity ,CHEMICAL vapor deposition - Abstract
Traditional thermally conductive materials are gradually losing their advantages as the electronics industry develops rapidly. Polymers are in urgent need of a material with high thermal conductivity, stable structure, good mechanical properties and oxidation resistance, which makes hexagonal boron nitride (h-BN) an excellent heat transfer filler for polymer composites. Boron nitride nanosheets (BNNS) are monolayers of hexagonal boron nitride, and theoretical studies have shown that BNNS have a higher thermal conductivity than h-BN (up to 400Wm
-1 K-1 , in-plane). This paper provides a comprehensive review of various methods for preparing BNNS, including mechanical exfoliation, liquid phase sonication exfoliation and chemical vapor deposition (CVD). In addition, various factors affecting the thermal conductivity of BNNS, including grain boundary, grain size and defects, are also discussed. Then, the influence of BNNS as filler on the thermal conductivity of the polymer was further discussed. Finally, this paper summarizes the existing BNNS applications and lists the application scenarios of BNNS in various fields. The purpose of this review is to summarize the previous work and put forward the prospect and future development direction of preparing high thermal conductivity BNNS-included polymer composites, so as to stimulate the research and improvement of new preparation methods for BNNS and promote its practical application as heat transfer materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
22. On the origin of twist in 3D nucleation islands of tetrahedrally coordinated semiconductors heteroepitaxially grown along hexagonal orientations.
- Author
-
Vennéguès, P., Largeau, L., Brändli, V., Damilano, B., Tavernier, K., Bernard, R., Courville, A., Rennesson, S., Semond, F., Feuillet, G., and Cornet, C.
- Subjects
NUCLEATION ,SEMICONDUCTORS ,ISLANDS ,DISLOCATION density ,BORON nitride - Abstract
In the first part of this paper, we present a model that explains and determines quantitatively the twists between nucleation islands in the case of a Volmer–Weber heteroepitaxial growth of tetrahedrally coordinated semiconductors along hexagonal orientations. These twists are caused by the network of the screw components of the 60° misfit dislocations. The orientations of the screw components are distributed randomly, and the maximum twist is obtained when all the screw components have the same orientation. The maximum twists are related to the density of misfit dislocations and, therefore, increase with the mismatch between the deposited materials and their substrate. In the second part of the paper, we study five systems having a large distribution of mismatches from 4% to 19%. For the four systems fulfilling the conditions necessary for the application of the model (plastic relaxation of grown islands), the measured maximum twists fit with the calculated values, thereby validating the model. The twists of nucleation islands are related to the mismatch and are, therefore, intrinsic to the material systems. The defects created at the coalescence of twisted islands determine the initial microstructure/defect distribution of the nucleation layer. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. Highly thermally conductive polymer composite enhanced by constructing a dual thermal conductivity network.
- Author
-
Wang, Zhanyi, Wang, Xuan, Zhang, Zhonghua, Liang, Liang, Zhao, Zhihang, and Shi, Jiahao
- Subjects
CONDUCTING polymer composites ,THERMAL conductivity ,POLYMER networks ,EPOXY resins ,CONDUCTING polymers ,BORON nitride ,COMPOSITE materials ,DIELECTRIC properties ,THERMAL resistance - Abstract
Constructing interconnected thermally conductive networks in a polymer matrix is essential for efficient heat transport in thermally managed materials. Thermally conductive network structures typically have meager thermal resistance, and heat transfer into the material is rapidly exported along such networks. However, increasing the thermally conductive networks inside the polymer matrix is still challenging. This paper prepared high thermal conductivity composites with "primary‐secondary" thermal conductivity networks by combining two processes: constructing three‐dimensional thermally conductive skeletal networks and physically blending fillers, using epoxy resin as the matrix. The performance test results showed that the thermal conductivity of the composites reached 1.65 W/(m K) when the boron nitride (BN) content reached 33.5 wt%, which was 842.8% and 150% higher than that of pure epoxy (EP) and composites with randomly dispersed fillers. This highly efficient heat transfer behavior is mainly due to the synergistic effect of the two‐level thermally conductive network, which weakens the scattering effect of phonons to a great extent. Also, the dielectric properties of the composite material, especially the transport of carriers inside the material under strong electric fields, were discussed in this paper. This work provides ideas and methods for preparing electrical and electronic devices applied to high power density. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
24. Support Effect of Boron Nitride on the First N-H Bond Activation of NH 3 on Ru Clusters.
- Author
-
Zhao, Li, Zhuang, Huimin, Zhang, Yixuan, Ma, Lishuang, Xi, Yanyan, and Lin, Xufeng
- Subjects
BORON nitride ,TRANSITION metal catalysts ,RUTHENIUM catalysts ,DENSITY functional theory ,METAL clusters ,HETEROGENEOUS catalysis - Abstract
Support effect is an important issue in heterogeneous catalysis, while the explicit role of a catalytic support is often unclear for catalytic reactions. A systematic density functional theory computational study is reported in this paper to elucidate the effect of a model boron nitride (BN) support on the first N-H bond activation step of NH
3 on Run (n = 1, 2, 3) metal clusters. Geometry optimizations and energy calculations were carried out using density functional theory (DFT) calculation for intermediates and transition states from the starting materials undergoing the N-H activation process. The primary findings are summarized as follows. The involvement of the model BN support does not significantly alter the equilibrium structure of intermediates and transition states in the most favorable pathway (MFP). Moreover, the involvement of BN support decreases the free energy of activation, ΔG≠ , thus improving the reaction rate constant. This improvement is more obvious at high temperatures like 673 K than low temperatures like 298 K. The BN support effect leading to the ΔG≠ decrease is most significant for the single Ru atom case among all three cases studied. Finally, the involvement of the model BN may change the spin transition behavior of the reaction system during the N-H bond activation process. All these findings provide a deeper insight into the support effect on the N-H bond activation of NH3 for the supported Ru catalyst in particular and for supported transition metal catalysts in general. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
25. AA h BN crystal, basic structure of boron nitride nanotubes
- Author
-
Dong Ju Moon, Jae-Kap Lee, Jin-Gyu Kim, Sang Gil Lee, Yesong Kim, and Seunggun Yu
- Subjects
Materials science ,aah bn crystals ,Biochemistry ,Crystal ,chemistry.chemical_compound ,morphology ,transmission electron microscopy ,boron nitride nanotubes ,General Materials Science ,Texture (crystalline) ,High-resolution transmission electron microscopy ,AA h BN crystals ,Crystallography ,General Chemistry ,Condensed Matter Physics ,Research Papers ,helical structures ,Electron diffraction ,chemistry ,QD901-999 ,Transmission electron microscopy ,Boron nitride ,Helix ,electron diffraction ,Orthorhombic crystal system - Abstract
For the first time, AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported. The structure of BN nanotubes is reinterpreted as a helix, resulting from texture and helical growth of the AA h BN crystal used., AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported here. This new AA h BN crystal exhibits a ‘linear’ morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) ‘diagonal’ electron-diffraction pattern, which have been experimentally demonstrated in this article. It is also demonstrated that this new crystal is the basic structure of multi-walled BN nanotubes (BNNTs) existing in the form of a helix. The helical AA h BNNTs exist in a metastable phase owing to 〈200〉 texture growth of the orthorhombic crystal, where the energy is ∼15 meV higher than that of stable AB or AA′ BN. It is shown that the typical scanning electron microscope ‘fluffy cotton-like’ morphology of BNNTs is due to secondary growth of diverse BN sheets (including mono-layers) on incoherently scrolled wall strands of BNNTs, providing further evidence for the helical structure with HRTEM evidence for a left-handed helix.
- Published
- 2021
26. Recent Progress in Cubic Boron Nitride (c-BN) Fabrication by Pulsed Laser Annealing for Optoelectronic Applications.
- Author
-
Haque, Ariful, Taqy, Saif, and Narayan, Jagdish
- Subjects
LASER annealing ,PULSED lasers ,OPTOELECTRONICS ,EPITAXY ,TRANSMITTANCE (Physics) ,OPTICAL films ,THIN films ,N-type semiconductors ,BORON nitride - Abstract
Phase-pure crystalline cubic boron nitride (c-BN) thin films are of immense scientific and technical interest because of their suitable properties for optoelectronic and high-power applications, high thermal conductivity and hardness, chemical inertness to ferrous materials in high-temperature and caustic environments, and high optical transmittance over a broad wavelength range from the ultraviolet (UV) to the visible spectrum. However, the lack of controlled fabrication techniques for high-quality c-BN films significantly affects the reliable practical applications of this material. Recently, phase-pure single-crystal c-BN and a new phase of BN with unique properties, called quenched-BN (Q-BN), have been synthesized using a pulsed laser annealing (PLA) technique to overcome the current impediments in c-BN synthesis. This review paper comprehensively examines the current status of analytical research on the growth, characterization, and properties (optical and electrical) of c-BN films fabricated by different synthesis techniques, with a particular emphasis on the immensely promising PLA technique. In particular, the paper focuses on the processes used to obtain phase-pure c-BN films via epitaxial growth, characterization of defects and interfaces, and control of the structural, electrical, and optical properties of these films by controlling the growth parameters, including the laser–solid interaction for the direct conversion of nanocrystalline hexagonal boron nitride (h-BN) into crystalline c-BN using the PLA technique. The latest developments in c-BN electronics are also discussed, with a focus on producing p-and n-type conductivity using different dopants to achieve dopant concentrations far beyond the retrograde thermodynamic solid solubility limits. Finally, the future prospects and possible applications in emerging areas are discussed, as well as the goals and guidelines for future research of PLA-grown c-BN films. A comprehensive overview of the properties, application, characterization, shortcomings, and future prospects of c-BN [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Investigation of Dual-Layer Si-ITO-Dielectric Based Hybrid Plasmonic Electro-Absorption Modulator at 1.55 µm Wavelength.
- Author
-
Das, Himanshu R.
- Subjects
DIELECTRIC materials ,INTEGRATED circuits ,HAFNIUM oxide ,BORON nitride ,INSERTION loss (Telecommunication) - Abstract
In this paper, a dual-layer plasmonic material-based electro-absorption modulator (EAM) is designed and investigated. Indium-tin-oxide (ITO), along with dielectric materials such as boron nitride (hBN) and hafnium dioxide (HfO
2 ), is integrated into the Si waveguide for tuning the light propagating inside the device. The device showed enhanced performance in terms of extinction ratio (ER) = 34.48 dB/µm, the figure of merit (FOM) = 493, and insertion loss (IL) = 0.06 dB/µm for On-state at 1.55 µm wavelength. Also, the dual-state behavior of the EAM was observed and investigated. An IL of 22.22 dB/µm and 25.39 dB/µm was observed for the Off-On and On-Off configurations, respectively. A modulation frequency (${f_{3dB}}$ f 3 dB ) of 1.72 THz and 340 GHz was achieved for the EAM with hBN and HfO2 as the dielectric material. The investigated EAM with different dielectric materials has the potential to be integrated into future-generation photonic integrated circuits (PICs). [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
28. Poly(lactic acid) based Pearl Layer Moistureproof Membrane for Flexible Laminated Packaging.
- Author
-
Ma, Ying, Zhao, Jingming, Wang, Yanqing, Pang, Bo, Wu, Yumin, and Gao, Chuanhui
- Subjects
FLEXIBLE packaging ,LACTIC acid ,POLYLACTIC acid ,BRICKS ,BORON nitride ,COMPOSITE membranes (Chemistry) ,POLYPROPYLENE oxide ,WATER vapor - Abstract
The development of bio‐based polymer materials, such as polylactic acid (PLA) ‐based polymers, is an effective strategy to reduce dependence on petrochemical‐based polymers. However, the preparation of bio‐based polymers with high barrier properties is a major challenge. To overcome this challenge, a nacreous layer structure with a ' brick and mud ' pattern is mimicked to improve the overall performance of the material. In this paper, Poly (L‐lactic acid) (PLLA) and Polypropylene Glycol (PPG) was combined to prepare bio‐based polyurethane (PU‐PLLA), which is used as the slurry structure of nacreous layer. The bio‐based biomimetic composite membrane (PU‐PLLA/BN) is then obtained by adding boron nitride (BN, brick structure of pearl layer) to it. The water vapor permeability test results show that the permeability of PU‐PLLA material can be reduced by more than 50% by 5 wt.% BN, which is because the addition of BN can increase the length and tortuosity of the gas molecular diffusion path in the composite. Therefore, this pearl‐inspired PU‐PLLA/BN film has excellent moisture resistance, which opens up a broad road for the practical application of PLLA in flexible laminated packaging. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Enhanced thermal conductivity of epoxy resin by incorporating three-dimensional boron nitride thermally conductive network.
- Author
-
Wang, Xubin, Zhang, Changhai, Zhang, Tiandong, Tang, Chao, and Chi, Qingguo
- Subjects
- *
THERMAL conductivity , *THERMAL insulation , *POWER semiconductors , *FOURIER transform spectrometers , *BORON nitride , *SCANNING electron microscopes , *PACKAGING materials , *EPOXY resins - Abstract
Packaging insulation materials with high thermal conductivity and excellent dielectric properties are favorable to meet the high demand and rapid development of third generation power semiconductors. In this study, we propose to improve the thermal conductivity of epoxy resin (EP) by incorporating a three-dimensional boron nitride thermally conductive network. Detailedly, polyurethane foam (PU) was used as a supporter, and boron nitride nanosheets (BNNSs) were loaded onto the PU supporter through chemical bonding (BNNS@PU). After immersing BNNS@PU into the EP resin, EP-based thermally conductive composites were prepared by vacuum-assisted impregnation. Fourier transform infrared spectrometer and scanning electron microscope were used to characterize the chemical bonding and morphological structure of BNNS@PU, respectively. The content of BNNS in BNNS@PU/EP composites was quantitatively analyzed by TGA. The results show that the thermal conductivity of the BNNS@PU/EP composites reaches 0.521 W/m K with an enhancement rate η of 30.89 at an ultra-low BNNS filler content (5.93 wt. %). Additionally, the BNNS@PU/EP composites have excellent dielectric properties with the frequency range from 101 to 106 Hz. This paper provides an interesting idea for developing high thermal conductivity insulating materials used for power semiconductor packaging. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Tribology of vegetal oils as base for eco-friendly nano additivated lubricants.
- Author
-
GUGLEA, Dionis, CRISTEA, George Catalin, DELEANU, Lorena, IONESCU, Traian Florian, OJOC, George Ghiocel, DIMA, Dumitru, and GEORGESCU, Constantin
- Subjects
BASE oils ,TRIBOLOGY ,RAPESEED oil ,MECHANICAL wear ,SLIDING wear ,FRICTION ,BORON nitride ,DRY friction - Abstract
This paper presents an analysis based on experimental data for pointing out the behavior of rapeseed oil when it is additivated with a modifier of friction and wear, the nano hexagonal Boron nitride. All tests are done on a four-ball machine, in mild regime. Test parameters were sliding velocity (0.38 m/s, 0.53 m/s, 0.69 m/s, corresponding to the spindle rotational speed of the four-ball machine of 1000 rpm, 1400 rpm, 1800 rpm (±10 rpm),), force (100 N – 300 N), test duration 1 h. There were calculated the average friction coefficient during the test and the average wear scar diameter (WSD) for each test. The same test parameters were done twice and the values in this paper are the average of these two tests. Wear was discussed for the same velocity range, in terms of WSD, but for comparing tests with different sliding velocity (implicitly, different sliding distances), there was used the wear rate of the wear scar diameter. The results on wear parameters, using additivated rapeseed oil, do not show spectacular results for the parameters tested in this study, but underline the “insensitivity” of the lubricants to the variation of the test regime (especially with respect to sliding speed), which is desirable for certain applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
31. Kinetics effect of hydrogen passivation on the zigzag edge growth of h-BN.
- Author
-
Zhao, Wenjing and Zhu, Junyi
- Subjects
PASSIVATION ,BORON nitride ,HYDROGEN ,DIMERS - Abstract
Edge kinetics in 2D structures has been a key to understanding the growth. In this paper, the effect of hydrogen passivation on the growth of hexagonal boron nitride (h-BN) was studied. Without hydrogen, the filling process of the gap on bare edges of h-BN is difficult because of the formation of dimers that distorts the edge. With hydrogen passivation, such difficulty can be largely reduced. In addition, hydrogen passivation can reduce the edge bending to the substrate. In summary, the amount of hydrogen passivation during the growth is the long-ignored parameter and can be the key to a good crystal quality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Exploring multi-dimensional properties: field emission and electrochemical response of MoS2 nanoflowers on carbon cloth.
- Author
-
Bankar, Prashant K., Thombare, Balu R., Gavhane, Dnyaneshwar S., Kulkarni, Shrikant, Lole, Gaurav S., Daware, Krishna D., More, Mahendra M., Patil, Shankar I., and Dusane, Pravin R.
- Subjects
FIELD emission ,CARBON fibers ,BORON nitride ,NANOSTRUCTURED materials ,NANOCOMPOSITE materials ,ENERGY storage ,THYRISTORS - Abstract
Discovery of graphene and its distinctive set of properties and application worthiness led to a massive increase in researcher's attention in two-dimensional layered materials. There are various two-dimensional layered materials like graphene, graphyne, borophene, germanene, silicene, hexagonal boron nitride, MXenes, and transition metal dichalcogenides. Transition metal dichalcogenides especially dichalcogenide of molybdenum are being recognized as an alternative to graphene, due to their exceptional properties and potential for use in various domains. Owing to high surface area and high aspect ratio, nanostructured materials and nanocomposites have been recognized as potential field emitters and supercapacitor electrode. Therefore, an attempt has been made to hydrothermally synthesize MoS
2 nanoflowers on carbon paper and investigate their field emission and super-capacitive behavior. We have demonstrated that MoS2 –carbon paper nanocomposite can be competitive with various other well-known field emitters. Further, we have established that a stable field emission current can be measured with a turn-on field as low as 0.94 V/μm and a field enhancement factor up to ~ 5373 at 1 mm cathode–anode separation. Owing to the low turn-on field and its morphology, MoS2 –carbon paper nanocomposite could be explored for field emission-based displays, field emission lamps, and vacuum electronic components and devices. The highest specific capacitance of 137 F.g−1 was calculated for NaOH electrolyte and highest saturation potential is observed for Na2 SO4 electrolyte. For NaOH, the area under the curve decreases with increasing electrolyte concentration, and the maximum area under the curve is observed in the case of 0.5 mol.cc−1 concentration. Along with field emission application, the experimental results also propose the multifunctional potential of MoS2 –carbon paper nanocomposite in super-capacitors and energy storage. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
33. Bilayer C 60 Polymer/ h -BN Heterostructures: A DFT Study of Electronic and Optic Properties.
- Author
-
Chernozatonskii, Leonid A. and Kochaev, Aleksey I.
- Subjects
HETEROSTRUCTURES ,ELECTROOPTICAL devices ,POLYMER networks ,SUBSTRATES (Materials science) ,BORON nitride ,POLYMER structure ,FULLERENE polymers - Abstract
Interest in fullerene-based polymer structures has renewed due to the development of synthesis technologies using thin C
60 polymers. Fullerene networks are good semiconductors. In this paper, heterostructure complexes composed of C60 polymer networks on atomically thin dielectric substrates are modeled. Small tensile and compressive deformations make it possible to ensure appropriate placement of monolayer boron nitride with fullerene networks. The choice of a piezoelectric boron nitride substrate was dictated by interest in their applicability in mechanoelectric, photoelectronic, and electro-optical devices with the ability to control their properties. The results we obtained show that C60 polymer/h-BN heterostructures are stable compounds. The van der Waals interaction that arises between them affects their electronic and optical properties. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
34. Copper Modified Boron Nitride And Graphene Combined To Self-Assemble Three-Dimensional Thermal Conductivity Framework to Improve the Thermal Conductivity of Epoxy Resin.
- Author
-
Li, Shuo, Wu, Wei, Drummer, Dietmar, Tomiak, Florian, Wang, Yi, Lu, Zijian, and Zhao, Xintong
- Abstract
With the development of integrated circuits and the miniaturization/ integration of electronic devices, heat dissipation solutions have become an increasingly important issue. The thermal conductivity of polymer-based thermal management materials is typically influenced by the amount of incorporated fillers. However, an innovative solution to increase the thermal conductivity without increasing the total filler content is the improvement of the filler connectivity by using specific surface modifications. Surface modifications using thermal conductive submicron particles can reduce the interfiller distances, acting as thermal bridges between the particles. In this paper, copper submicron particles modified BN (BN@CuSMPs) have been prepared by in situ reduction and mixed with graphene oxide (GO). A three-dimensional BN@CuSMPs/rGO aerogel (CBGA) framework with "point-surface" connection has been prepared by using the self-assembly mode of GO. CBGA/EP composites were then prepared using epoxy resin (EP) as matrix and a vacuum assisted impregnation method. The thermal conductivity of CBGA/EP composites has been found to be 1.918 W m
−1 K−1 using a filler content of 19.61%, which was 12.8% higher than that of BN/rGO/EP composites and 909.5% higher than that of pure EP. The thermal resistance of the composites was analyzed using the Foygel model. It was found that the introduction of CuSMPs effectively decreased the thermal resistance between the BN particles, forming a thermal conductive three dimensional network inside the polymer-based material system. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
35. Electrical conduction properties of PP-based nanocomposite with high thermal conductivity for HVDC cable insulation.
- Author
-
Li, Jing, Gao, Yu, Liu, Baixin, Guo, Chenyi, Gao, Junguo, Chen, Yu, and Du, Boxue
- Subjects
THERMAL conductivity ,NANOCOMPOSITE materials ,SURFACE potential ,ELECTRIC conductivity ,ELECTRIC fields ,BORON nitride - Abstract
This paper reports on thermal and electrical conduction properties of polypropylene (PP)-based nanocomposite used for high voltage direct current cable insulation. To improve the thermal conductivity of the PP/propylene-based elastomer (PBE) blend (noted as PB), boron nitride (BN) nanosheets with high thermal conductivity are added. The pretreatment process through template method is to obtain a three-dimensional (3D) network structure composed of BN nanosheets (noted as 3DBN). Then the 3DBN is added into the PP/ PBE blend, in which the 3D networks are locally arranged and the other BN nanosheets are randomly dispersed. Thermal conductivity is estimated, while electrical conductivity is measured under electric fields of 5–40 kV mm
−1 at various temperatures. Carrier trap distribution is derived from isothermal surface potential decay method. In addition, the microstructure and crystallization characteristics of the nanocomposites are measured. The results show that the thermal conductivity of the PP/PBE blend is improved obviously by the addition of the locally arranged 3DBN, and that of PB-3DBN-10 is increased by 16% compared with that of PB. Deep traps are introduced by the dispersed BN nanosheets and the electrical conduction is reduced, which becomes increasingly evident with the filler content and temperature. It is suggested that the introduction of thermal conductive fillers with a 3D network structure and well-dispersed state can synergistically enhance the thermal conductivity and insulation performances of the PP-based material. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
36. First-principles study of bilayer hexagonal structure CrN2 nanosheets: A ferromagnetic semiconductor with high Curie temperature and tunable electronic properties.
- Author
-
Gao, Yuan and Zhou, Baozeng
- Subjects
- *
CURIE temperature , *MAGNETIC materials , *HIGH temperatures , *SEMICONDUCTORS , *MAGNETIC anisotropy , *INTERNAL friction , *BORON nitride - Abstract
Two-dimensional magnetic materials have been increasingly studied and discussed in the field of spintronics due to their unique electronic properties, high spin polarizability, and a variety of magnetic properties. In this paper, we report a new two-dimensional bilayer hexagonal monolayer material bilayer hexagonal structure (BHS)-CrN2 by first-principles calculations. The BHS-CrN2 nanosheet is an intrinsic ferromagnetic semiconductor material, and the Curie temperature obtained by Monte Carlo simulation is 343 K. The absence of a significant imaginary frequency in the phonon spectrum indicates the dynamic stability of BHS-CrN2. After ab initio molecular dynamics simulation, the supercell of BHS-CrN2 remains a complete structure, indicating its thermal stability. The calculated elastic moduli satisfy the Born–Huang criterion, indicating that the BHS-CrN2 system has good mechanical stability. Interestingly, the compressive strain and O atom doping can transform the electronic structure of BHS-CrN2 from a semiconductor to a half-metal, and the Curie temperature of BHS-CrN2 can be further increased to 1059 K when a 5% tensile strain is applied. Furthermore, the BHS-CrN2 in the ferromagnetic state shows a significant in-plane magnetic anisotropy energy of 0.01 meV per Cr, and the CrP2 and CrAs2 show a large out-of-plane magnetic anisotropy energy of 0.207 and 0.988 meV per Cr, respectively. The results show that the intrinsic ferromagnetic semiconductor BHS-CrN2 has good stability, high Curie temperature, and tunable magnetic properties, which is a promising material for room-temperature spintronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. An Automated Particle Size Analysis Method for SEM Images of Powder Coating Particles.
- Author
-
Liang, Can, Jia, Zijian, and Chen, Rui
- Subjects
SCANNING electron microscopy ,POWDER coating ,PARTICLE analysis ,CONVOLUTIONAL neural networks ,BARIUM titanate ,NIOBIUM oxide ,BORON nitride - Abstract
The particle size of powder coatings is an important factor affecting flow and fluidization performance, which in turn determines the quality of the coating. Powder coating particles, such as boron nitride, titanium dioxide, barium titanate, niobium oxide, and tungsten oxide, can be seen in SEM images as circular or polygonal shapes, with irregular edges and sizes, as well as aggregation and stacking between them. This paper introduces a novel method of automatic particle identification and size analysis applied in SEM images for the investigation of coating quality. Firstly, a fast gradient segmentation algorithm (Split–Merge) is utilized to automatically generate samples through determining the adhesive particles and particle groups. The samples are then manually checked and corrected to further segment the particles in order to form the dataset. Finally, the YOLOv5, a mature target detection algorithm, is used to train the labeled data in order to produce a multi-target detection recognition model. The model can be applied to identify more pictures of the same substance, and the particles' long and short axes are estimated using the elliptical coverage of the particles within the identified image boundary box. Experiment results from four kinds of powders suggest that this method can provide automatic particle size analysis for industrial SEM particle images. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. The influence of microtexture tools on the geometric morphology of serrated chips based on stress triaxiality.
- Author
-
Guo, ShuYu, Fan, Lin, He, Yan, Geng, BoHan, Chen, MingQi, and Wang, Yuhang
- Subjects
BORON nitride ,FINITE element method ,STRESS concentration ,CRACK propagation (Fracture mechanics) ,QUALITY of life - Abstract
Purpose: This study aims to investigate the effect of microtextured tools on the geometric morphology of serrated chips, and further improve the cutting performance of polycrystalline cubic boron nitride (PCBN) tool and extend the tool life and the surface quality of the machined surface. Design/methodology/approach: A three-dimensional finite element cutting model of hardened steel AISI D2 with microtextured PCBN tools were established using the finite element software Abaqus, and cutting tests were carried out. Furthermore, the stress distribution in the primary deformation zone was investigated based on the triaxiality of stress, and the influence of microtexture on the geometric morphology of serrated chips and crack development was researched. Findings: The results show that compared with nontexture tools, elliptical pits and wavy grooves microtexture tools have lower serrated degree Gs, higher serrated frequency f per unit length and more miniature serrated step Pc. The serrated phenomenon is intensified because the tensile stress zone of chips generated by nontextured tools is longer than that of elliptic pits and wavy grooves microtexture tools. Simultaneously, the maximum value of triaxiality in the tensile stress zone achieved by nontexture tools is larger than that of the two microtexture tools, and chips obtained by nontextured tools are more susceptible to propagation fractures. Originality/value: This paper mainly studies the effect of microtexture on chip microgeometry, which is relatively little studied at present. At the same time, this paper has a certain engineering significance for PCBN tool turning hardening steel. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0149/ [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Excellent Thermal and Dielectric Properties of Hexagonal Boron Nitride/Phenolic Resin Bulk Composite Material for Heatsink Applications.
- Author
-
Danilov, Egor A., Samoilov, Vladimir M., Kaplan, Innokenty M., Medvedeva, Elena V., Stepashkin, Andrey A., and Tcherdyntsev, Victor V.
- Subjects
PHENOLIC resins ,DIELECTRIC properties ,BORON nitride ,THERMAL properties ,DIELECTRIC loss ,COMPRESSION molding ,COMPOSITE materials - Abstract
In the present paper, we report polymer composites based on phenolic resin filled with hexagonal boron nitride; hot compression molding coupled with solution-based mixing were used to manufacture the composites. The paper presents experimental results on the physical and physicochemical properties of the obtained composites: thermal stability in air and argon, dielectric constant and dielectric loss tangent, active electrical resistance, thermal conductivity (mean and anisotropy), and mechanical strength. It is shown that the proposed technique of composite manufacturing, including the application of high-process pressures, makes it possible to obtain materials with high anisotropy of thermal conductivity, extremely high-filler content, and excellent dielectric properties, all of which are very important for prospective highly efficient lightweight heatsink elements for electronic devices. Experimental values of thermal conductivity and dielectric constant were analyzed using known mathematical models. Experimental values for thermal conductivities (up to 18.5 W·m
−1 ·K−1 ) of composites at filler loadings of 65–85 vol.% are significantly higher than published data for bulk boron nitride/polymer composites. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
40. 氮化硼功能化改性高分子导热复合 材料的制备及性能研究进展.
- Author
-
柯 雪, 董 姗, 刘婵玉, 李梦莎, 游 峰, 江兵兵, 江学良, and 姚 楚
- Abstract
Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
41. Improving the thermal conductivity of PMIA/EP composites by the synergistic effect of modified boron nitride and graphene oxide.
- Author
-
Yue, Mengjie, Pu, Zejun, Wu, Fang, Zhu, Rongli, Wang, Xu, Yu, Dayang, and Zhong, Jiachun
- Subjects
- *
THERMAL conductivity , *GRAPHENE oxide , *BORON nitride , *EPOXY resins , *COMPOSITE materials , *THERMAL stability - Abstract
In this study, h-BN-OH was obtained by hydroxylating h-BN and subsequently KH560 was grafted onto the surface of h-BN-OH, resulting in h-BN-KH560. The h-BN-KH560 was then dispersed in an epoxy resin (EP) to create an EP/h-BN-KH560 adhesive solution, with the content of h-BN-KH560 being varied. Graphene oxide (GO) was dispersed in PMIA precipitated fibers to produce PMIA/GO composite paper. Finally, the surface of the composite paper was evenly coated with the EP/h-BN-KH560 adhesive solution, and then PMIA/EP/GO/h-BN composites with different h-BN-KH560 contents and good thermal conductivity were prepared by hot pressing. The FTIR analysis confirmed the successful grafting of KH560 onto the surface of h-BN-OH. By utilizing h-BN-KH560 and GO as thermal conductive fillers, we achieved a higher thermal conductivity in the composite material, creating a "dual thermal conductivity network" compared to using a single filler. Additionally, the thermal conductivity increased as the content of h-BN-KH560 increased. At h-BN-KH560 contents of 20 wt%, 40 wt%, and 60 wt%, the thermal conductivities of the prepared PMIA/EP/GO/h-BN composites were 0.661 Wm−1K−1, 1.082 Wm−1K−1, and 1.206 Wm−1K−1, respectively. Importantly, the addition of the thermal conductive filler did not significantly affect the thermal stability of the composites. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. A Dual-Mode Pressure and Temperature Sensor.
- Author
-
Chai, Jin, Wang, Xin, Li, Xuan, Wu, Guirong, Zhao, Yunlong, Nan, Xueli, Xue, Chenyang, Gao, Libo, and Zheng, Gaofeng
- Subjects
PRESSURE sensors ,TEMPERATURE sensors ,TEMPERATURE coefficient of electric resistance ,TACTILE sensors ,CARBON nanotubes ,BORON nitride - Abstract
The emerging field of flexible tactile sensing systems, equipped with multi-physical tactile sensing capabilities, holds vast potential across diverse domains such as medical monitoring, robotics, and human–computer interaction. In response to the prevailing challenges associated with the limited integration and sensitivity of flexible tactile sensors, this paper introduces a versatile tactile sensing system capable of concurrently monitoring temperature and pressure. The temperature sensor employs carbon nanotube/graphene conductive paste as its sensitive material, while the pressure sensor integrates an ionic gel containing boron nitride as its sensitive layer. Through the application of cost-effective screen printing technology, we have successfully manufactured a flexible dual-mode sensor with exceptional performance, featuring high sensitivity (804.27 kPa − 1 ), a broad response range (50 kPa), rapid response time (17 ms), and relaxation time (34 ms), alongside exceptional durability over 5000 cycles. Furthermore, the resistance temperature coefficient of the sensor within the temperature range of 12.5 °C to 93.7 °C is −0.17% °C
−1 . The designed flexible dual-mode tactile sensing system enables the real-time detection of pressure and temperature information, presenting an innovative approach to electronic skin with multi-physical tactile sensing capabilities. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. A First-Principle Study of Two-Dimensional Boron Nitride Polymorph with Tunable Magnetism.
- Author
-
Qiao, Liping, Ma, Zhongqi, Yan, Fulong, Wang, Sake, and Fan, Qingyang
- Subjects
BORON nitride ,POISSON'S ratio ,BAND gaps ,MAGNETISM ,YOUNG'S modulus ,MAGNETIC properties - Abstract
Using the first-principles calculation, two doping two-dimensional (2D) BN (boron nitride) polymorphs are constructed in this work. The two doping 2D BN polymorphs B
5 N6 Al and B5 N6 C sheets are thermally stable under 500 K. All the B6 N6 , B5 N6 Al, and B5 N6 C sheets are semiconductor materials with indirect band gaps on the basis of a hybrid functional. The anisotropic calculation results indicate that Young's modulus (E) and Poisson's ratio (v) of the B6 N6 , B5 N6 Al, and B5 N6 C sheets are anisotropic in the xy plane. In addition, the magnetic properties of the B6 N6 , B5 N6 Al, and B5 N6 C sheets have also been investigated. According to the calculation of the magnetic properties, B6 N6 sheet does not exhibit magnetism, while it shows weak magnetism after doping carbon atom to the BN sheet. This paper explores the influence mechanism of doping different atoms on the basic physical properties of two-dimensional BN sheets. It not only constructs a relationship between structure and performance but also provides theoretical support for the performance regulation of BN materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
44. Conical Grinding Wheel Ultrasonic-Assisted Grinding Micro-Texture Surface Formation Mechanism.
- Author
-
Han, Jiaying, Jiang, Yiqi, Li, Xinrui, and Li, Qing
- Subjects
GRINDING wheels ,BORON nitride ,SURFACE properties ,RICE quality ,SURFACE analysis ,POSITIVE pressure ventilation - Abstract
The rotating ultrasonic-assisted grinding (RUAG) experiment of the conical grinding wheel generated the intermittent pit-shaped micro-texture on the surface of the workpiece, reducing thermal damage and improving the lubrication characteristics compared with conventional grinding (CG). To further optimize the surface properties, this paper studied the formation mechanism of micro-texture. This study used as basis the theory that micro-debris volume equals the macroscopic material removal one to establish the mathematical equation of grinding depth. Thereafter, formulas of micro-texture feature parameters, including pit length, pit depth, and texture spacing were deduced. The solved microscopic grinding depth was alternatingly positive and negative, indicating that the alternating separation between the grinding grain and workpiece caused intermittent pits in the grinding. Through response surface analysis (RSA), this paper analyzed the relationships among macroscopic grinding depth, micro-texture feature parameters, and machining parameters (i.e., amplitude, feed rate, and rotational speed). Single-factor experiments of machining parameters, with finite element simulation and experiment methods, were performed to verify the theoretical micro-texture features. The simulated program formed three-dimensional surfaces with micro-textures. Their measurement results were consistent with the theoretical ones. Experimental results proved that the range of pit length covers the theoretical ones, further verifying the accuracy of the grinding depth model. For this grinding wheel, the 8–10 μm amplitude was optimal for better roughness, lubrication, and thermal damage. Roughness was improved when increasing the rotational speed or reducing the feed rate based on the experiment. If the rotational speed and feed rate exceed the limiting values, then continuous grinding will break down the abrasive grains and even damage the cubic boron nitride (CBN) coating. Experimental results likewise showed that the pit shape was closely related to the surface properties, which deserves further investigation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
45. One-pot fabrication of an anisotropic thermally conductive boron nitride/polyvinyl alcohol composite film based on salting-out effect.
- Author
-
Zhao, Zheng-Bai, Chen, Wang-Fei, Wang, Yang, Cong, Hong-Min, and Yan, Chao
- Subjects
POLYVINYL alcohol ,CONDUCTING polymer composites ,BORON nitride ,THERMAL conductivity ,SODIUM sulfate - Abstract
The directional arrangement of thermally conductive lamellar fillers is an effective way to improve the thermal conductivity of polymer composites, which is achieved by the pre-construction of the thermal conductive network in most of the current research. Simplifying the process of the lamellar fillers' directional arrangement is significant for practical application, and a novel and facile fabricating method is reported in this study. First, the amino hexagonal boron nitride (BNNH
2 ) was mixed with polyvinyl alcohol (PVA) water solution to prepare PVA/BNNH2 mixture. Subsequently, the mixture was dropped on the saturated sodium sulfate solution to obtain PVA/BNNH2 film through the salting-out function of PVA. The in-plane thermal conductivity of the as-prepared PVA/BNNH2 film can reach 3.09 W m−1 K−1 with 30 wt% filler content. Furthermore, the PVA/BNNH2 films present excellent flexibility and good insulation. This paper may provide a new strategy for fabricating anisotropic thermally conductive polymer composites. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
46. Experimental analysis and optimization of machinability of superalloys using carbide inserts.
- Author
-
Veeranaath, V., Krishna, Sai, and Nitheesh, S. K.
- Subjects
MACHINABILITY of metals ,HEAT resistant alloys ,INCONEL ,CHROMIUM-cobalt-nickel-molybdenum alloys ,BORON nitride ,INTERFACIAL friction ,BORON carbides - Abstract
Aeronautical superalloys, like nickel and titanium-based metals, are most normally employed in the making of various spares because of their exclusive blend of possessions like improved strength, less corrosion, and degradation. The cutting of these materials is well-thought-out to be very tough and hard because of the need of high energy feeding for cutting. The other factors which induce a hindrance to cut are more heat development, friction at the interface, and high machining temperature. The inserts with healthier hardness like carbides and boron nitride are recurrently used for machining superalloys. In the current scenario, more researchers are focused to gain a better knowledge of the inserts, machining constraints, and machining time and its functionality in the workpiece plays a very significant and dominant role in the metal removal of superalloys. Thus, this paper involves the analysis of orthogonal machining of superalloys with a motive to advance the surface integrity, reduce the wear and increase productivity. Ti6Al4V and Inconel 718 are the super alloys taken for the study and carbide inserts are used for orthogonal cutting of the same. This paper presents the impacts of the most noteworthy processing constraints on the various machineability characteristics which include machining force, exterior finish, insert wear, and chip structure. A structured methodology is also employed for the optimising of several restraints on output response. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. Preparation and properties of ABS/BNNS composites with high thermal conductivity for FDM.
- Author
-
Chen, Caifeng, Zhong, Wuwen, Guo, Junhao, Liu, Kai, and Wang, Andong
- Subjects
THERMAL conductivity ,BORON nitride ,THERMAL stability ,ENGINEERING plastics ,PLASTICS engineering ,NANOSTRUCTURED materials - Abstract
Acrylonitrile-butadiene-styrene (ABS) resin is a widely used engineering plastic at present. Due to its excellent mechanical properties and high fluidity, it is utilized in fused deposition molding (FDM) technology. In this paper, boron nitride nanosheets (BNNS) were prepared by hydrothermal exfoliation and used as nano-fillers for ABS resin, and ABS/BNNS composite wires for FDM printing were prepared by melt blending method. The results showed that BNNS with fewer layers were obtained; the addition of BNNS to the ABS resin matrix could effectively enhance the thermal conductivity of the composites. When the addition amount of BNNS was 15 wt%, the thermal conductivity of the composite increased to 0.369 W/(m K), which was 120.06 % higher than that of pure ABS (0.174 W/(m K)). In addition, BNNS also improves the mechanical properties, thermal stability, and melt flow rate of the composites, thus making ABS composite wires more suitable for FDM printing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Effects of exchange coupling and external magnetic field on the magnetic characteristics of hexagonal boron nitride: A Monte Carlo study.
- Author
-
Fadil, Z., Raorane, Chaitany Jayprakash, Cahaya, Adam B., El Fdil, R., Karam, Steve, Khan, Aftab Aslam Parwaz, Vanaraj, Ramkumar, and Kim, Seong Cheol
- Subjects
MAGNETIC fields ,MONTE Carlo method ,BORON nitride ,FERRIMAGNETIC materials ,ISING model ,MAGNETIC devices ,TEMPERATURE effect - Abstract
The paper presents a study on the magnetic characteristics of hexagonal boron nitride using Monte Carlo simulations through the Metropolis algorithm. The study used the Blume-Capel Ising model to analyze the behavior of magnetizations and susceptibilities under the effect of the temperature, mixed exchange coupling, crystalline and external magnetic fields. The results show that the blocking temperature, where the magnetic atoms become magnetically frozen, increases as the exchange coupling interaction becomes weaker and as the external magnetic field increases. The findings indicate that the blocking temperature of the system is significantly influenced by the physical parameters employed in this study. Besides, the investigation at hand could serve as a foundation for researchers to innovate novel categories of spintronics and magnetic memory devices, featuring enhanced performance and functionality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. The effect of hexagonal boron nitride nanopowders addition on the mechanical behaviors of basalt fabric reinforced composites.
- Author
-
Bakal Gumus, Fatma and Yapici, Ahmet
- Subjects
COMPOSITE particles (Composite materials) ,BORON nitride ,BASALT ,FOURIER transform infrared spectroscopy ,AUTOMOTIVE materials ,EPOXY resins - Abstract
Purpose: The purpose of this paper is to investigate the effect of doping element on the structural, thermal properties, mechanical performance and the failure mechanism of hexagonal nano boron nitride (h-BN)-reinforced basalt fabric (BF)/epoxy composites produced by hand lay-up and vacuum bagging technique. h-BN particles doped to composite materials increased the tensile, bending and impact strength of the composite at certain rates while 1 Wt. % h- BN addition shows the highest tensile and flexural strength. Design/methodology/approach: The epoxy resin was doped with h-BN nanopowder at the certain rates (0, 1, 2 and 4 Wt.%) and the epoxy: hardener ratios used in the study were selected as 80%: 20% by weight. Then, with the aid of a roller by hand lay-up method, a mixture of epoxy + hardeners containing nanoparticles and nanoparticle-free were fed onto BFs, 12 layers of each dimension 30 cm × 30 cm. The surplus epoxy resin was moved away from the composite sheets using the vacuum bagging process and left to cure at room temperature for 24 h. ASTM D3039 for tensile, D7264 for three-point bending and D256 for Izod impact test were performed for the mechanical tests. After the tensile test, the morphologies of the fracture surface were examined with a stereomicroscope and various failure mechanisms are highlighted. Findings: In this study, a series of basalt/epoxy composites with h-BN nanopowders have been prepared to identify the effect of filler ratio on mechanical properties. It has been known from the results of mechanical experiments that the addition of h-BN improves the mechanical performance of materials at a certain rate. The tensile and flexural strengths of h-BN doped composites, increase for concentrations of 1 Wt.% h-BN, but decrease with the increasing content of it. The basalt/epoxy resin composite with higher mechanical properties could be a potential material in the automotive and aerospace industries. Originality/value: The aim of this study is to contribute to literature within the context of this new combination of composites and their mechanical properties, failure mechanisms. It presents detailed characterization of each composite by using X-ray differaction (XRD), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. Abnormal Time-Domain Current Spectrum of Inorganic Insulating Powder under DC Voltage.
- Author
-
Xue, Yucui, Guo, Wenmin, Sun, Yunlong, Li, Zhonghua, and Han, Yongsen
- Subjects
DIELECTRIC properties ,VOLTAGE ,BORON nitride ,MAGNESIUM oxide ,DIELECTRICS ,POWDERS - Abstract
The total current of dielectrics under DC voltage consists of relaxation current and conduction current, which contains the information about the relaxation polarization and conduction. The time-domain spectrum (TDS) is an effective method to study the dielectric properties of insulating dielectrics. In this paper, the TDS method is also used to study the dielectric properties of the compressed inorganic hexagonal boron nitride (BN) and magnesium oxide (MgO) insulating powders. It is interestingly found that these inorganic insulating powders shows an abnormal TDS, where the current decreases monotonically to a certain level at first and then increases with time while in normal TDS the current decreases monotonically with time and finally reaches a steady value which is conduction current. The experiments verify that the abnormal phenomenon is attributed to the moisture absorption of powders during the testing process, which causes an increase in conductivity and leads to the increasing current at the end of testing time. The insulating powder cannot be regarded as a time-invariant system during the measurement, and the time-varying characteristic is mainly manifested in conduction. A time-domain least squares fitting method is presented and is effective to eliminate the deviation from normal TDS. The results of this paper provide a reference for dealing with abnormal TDS. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.