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[Display omitted] • Quaternary Ag 2 SbBiSe 4 NCs are synthesized by a colloidal synthesis route. • Ag 2 SbBiSe 4 has a cubic crystal structure and a wide band gap. • Ag 2 SbBiSe 4 maintains low lattice thermal conductivity of ca. 0.34 W m−1K−1. • Modulation doping through Sn NCs is used to tune the TE performance of Ag 2 SbBiSe 4. • A maximum ZT value of 0.64 at 760 K and a high Vickers Hardness of ~185 Hv are obtained. Materials with low intrinsic thermal conductivity are essential for the development of high-performance thermoelectric devices. At the same time, the solution processing of these materials may enable the cost-effective production of the devices. Herein, we detail a high-yield and scalable colloidal synthesis route to produce Ag 2 SbBiSe 4 nanocrystals (NCs) using amine-thiol-Se chemistry. The quaternary chalcogenide material is consolidated by a rapid hot-press maintaining the cubic crystalline structure. Transport measurements confirm that n -type Ag 2 SbBiSe 4 exhibits an inherently ultralow lattice thermal conductivity of ca. 0.34 W m−1K−1 at 760 K. Moreover, a modulation doping strategy based on the blending of semiconductor Ag 2 SbBiSe 4 and metallic Sn NCs is demonstrated to control the charge carrier concentration in the final composite material. The introduction of Sn nanodomains additionally blocks phonon propagation thus contributing to reducing the thermal conductivity of the final material. Ultimately, a peak thermoelectric figure of merit value of 0.64 at 760 K is achieved for n -type Ag 2 SbBiSe 4 -Sn nanocomposites that also demonstrate a notable Vickers hardness of 185 HV. [ABSTRACT FROM AUTHOR]

With the increasing volume of synthetic fiber waste, interest in plastic reuse technologies has grown. To address this issue, physical and chemical recycling techniques for polyamide, a major component of textile waste, have been developed. This study investigates the remelting and reforming properties of four types of pristine and recycled polyamide 6, focusing on how the microstructural arrangement of recycled polyamides affects polymer fiber formation. DSC and FT-IR were used to determine the thermal properties and chemical composition of the reformed thin films. Differences in the elongation behavior of molten fibers during the spinning process were also observed, and the morphology of the resulting fibers was examined via SEM. Birefringence analysis revealed that the uniformity of the molecular structure greatly influenced differences in the re-fiberization process, suggesting that chemically recycled polyamide is the most suitable material for re-fiberization with its high structural similarity to pristine polyamide. [ABSTRACT FROM AUTHOR]

The aim of study is investigation of sintering temperature and hot cross-rolling on physical, mechanical and microstructural properties of Al-30 wt% B4C. The mixed powder (Al and B4C) was sintered by hot pressing at 550, 600 and 650 °C and was preheated at 500 °C for 20 min for hot cross-rolling. For characterization, density measurement following Archimedes principle, microhardness, XRD and FESEM was performed. Performing hot cross-rolling process can lead to decrease the size of B4C and uniform distribution. The results showed that the density and hardness of hot-pressed samples with increase in sintering temperature were increased. Also, after hot cross-rolling, the density and hardness of the samples were increased from 2.35 to 2.64 g/cm3, and 101 to 136.8 Vickers, respectively. Furthermore, the fracture toughness increased from 7.5 to 13.8 MPa m1/2. The sintering temperature at 650 °C and performing 25% hot cross-rolling led to a composite with the highest density. [ABSTRACT FROM AUTHOR]

In the current study, NiAl–TiB2 nanocomposite was produced by mechanical alloying and subsequent heat treatment. For this purpose, mixtures of pure Ni, Al, Ti, and B powders were milled in a ball mill for 20 h to produce NiAl-TiB2 nanocomposites containing 10, 20, and 30 at% TiB2. The heat treatment temperature was selected at 850 °C for 30 min which was determined by differential thermal analysis. X-ray diffractometer (XRD) was used to identify the existing phases. The XRD results showed the completion of alloying after heat treatment. Furthermore, the morphology of the powders and microstructure of the sintered samples were investigated by optical microscopy and field emission scanning electron microscopy. Results showed that the NiAl-20% TiB2 sample had the most homogeneous morphology. Then the powder mixture was hot pressed at 800 °C under 300 MPa. The density of the sample reached 95% after hot pressing. The sample containing 20% TiB2 was subjected to wear test under 5, 7, 10, and 13N loads by pin on disk method. Examination of the morphology of the worn surface and wear debris showed that spalling was the dominant wear mechanism. [ABSTRACT FROM AUTHOR]

Silver selenide (Ag2Se) is a promising thermoelectric material for near‐room temperature applications. This study proposes a fast, simple, and cost‐effective method for producing high thermoelectric performance bulk Ag2Se. Ag2Se powders were synthesized from Ag and Se powders via a one‐hour wet ball milling process, followed by the fabrication of bulk pellets through low‐temperature hot‐pressing (130–250 °C) with a mere 0.5‐hour holding time. Both Ag2Se powders and bulk pellets exhibited a single phase of Ag2Se with an orthorhombic structure. Moreover, uniform compositional distribution with the stoichiometric Ag : Se ratio was observed in all samples. Microstructural analysis revealed distinct grain boundaries in samples hot‐pressed below 190 °C, transitioning to grain coalescence was at 190 °C and 250 °C. The thermoelectric and transport measurements demonstrated that the electrical conductivity decreased and the Seebeck coefficient increased with hot‐pressing temperatures from 130 °C and 190 °C primarily due to reduced carrier concentrations. Thermal conductivity decreased with increasing hot‐pressing temperatures up to 190 °C, attributed to the weak chemical bonding of Ag2Se and the presence of defects. This combination resulted in a peak zT over 1.0 at 300 K, with an average zT close to 1.0 from 300 to 380 K. In comparison to other reported synthesis methods, the present approach offers significantly reduced processing time, simplicity, and cost‐effectiveness. Despite lower temperatures and shorter processing times, the method produces Ag2Se with zT values comparable to more intricate techniques. This fabrication route holds the potential for scalable mass production in the future. [ABSTRACT FROM AUTHOR]

The rapid increase in plastic usage today poses a significant threat to our environment and the planet. It contributes to global warming and negatively impacts biodiversity. Most plastic ends up in landfills, where it can take up to 1000 years to decompose. Shockingly, only 9% of the plastic produced annually is recycled, while an astounding 2 million plastic bags are used every minute worldwide. This paper highlights the primary goal of plastic recycling, with a particular focus on using plastic to manufacture roof tiles. The motivation behind this approach is that everyone deserves a decent roof over their heads. To achieve this, a well-balanced mixture of waste polypropylene (PP), quartz sand, and fly ash minerals was utilized in producing plastic roof tiles. The research employed a hot press process to prepare samples of all composite materials, and no cracks or fractures were observed on the surface of these samples. The results of this innovative process exceed the standards set for most building materials in terms of both mechanical and thermal properties, demonstrating a compressive strength of 99.8 MPa, a flexural strength of 35.6 MPa, and an impact energy absorption of 7.93 KJ/m2. Importantly, all samples exhibited zero percent water absorption, making these roof tiles ideal for insulation purposes. Additionally, the resulting roof tiles are lightweight and cost-effective compared to conventional options. [ABSTRACT FROM AUTHOR]

To produce samples for both material testing and molded sheets/parts, this article details an open-source scientific cold and hot press design. It consists of two independent and modular upper and lower plate (929 cm2) assemblies each containing four 125 W insulated steel strip heaters. The steel housing for these heaters is entirely modular and designed for ease of manufacture, assembly, and customization. This system allows a researcher with access to a hydraulic press to repurpose existing equipment into a multipurpose hot and cold press, or if an independent machine is warranted, an additional welded support frame and commercially available bottle jack offer standalone operation. By utilizing this small-scale hot press either in conjunction with a hydraulic press or on its own, samples can be produced to determine the critical material properties of any polymer, composite, or polymer blend. A series of modular molds allow for the rapid production of flat sheet stock and solid testing samples adhering to the ASTM D695 standard for rigid plastics tested in compression and ASTM D638 standard for testing plastics in tension. The sheet mold offers the user the ability to produce stock sheets that can be cut and assembled into 2.5-D applications with post processing.

Boron carbide is a notable ceramic, with its high hardness and low density. However, it suffers a sudden loss in strength under high shear stress. Doping boron carbide with Si/B is widely used to increase its resistance to amorphization. High purity boron and silicon hexaboride precursor powders are used for doping boron carbide, but these materials have high costs and supply chain constraints. This research investigated the effect of substituting lower purity B or using pure Si powder instead of SiB6 on materials' properties such as elastic and mechanical properties, microstructure, and amorphization resistances. It was observed that using lower‐purity boron or pure Si powder instead of SiB6 did not significantly affect critical properties, such as fracture toughness, hardness, or amorphization resistance. However, Young's modulus values decreased as B purity decreased and as Si was used instead of SiB6. These findings demonstrate that substituting precursor materials in Si/B co‐doped B4C is possible with little change in the material's properties. This facilitates the use of easier‐to‐access, cheaper production routes to be used for silicon‐doped boron carbide products. [ABSTRACT FROM AUTHOR]

During the recycling process of polyethylene terephthalate (PET), particles with low granulometry (refuse) may stick to the screw of the extruder and be discarded. In order to avoid its disposal, this research carries out a hot pressing of this refuse to allow its use. First, the ideal duration of hot pressing for this case was determined. Next, the resulting material was evaluated by drilling and manual sawing processes, and its mechanical properties were obtained by compression tests. The medium elastic modulus obtained by experimental tests was 1.13 GPa and, its medium strength, 68.5 MPa. Yet, the resulting material presented satisfactory performance by drilling and manual sawing processes.

Disposable surgical gowns are usually made from petroleum-based synthetic fibers that do not naturally decompose, impacting the environment. A promising approach to diminish the environmental impact of disposable gowns involves utilizing natural fibers and/or bio-based synthetic fibers. In this study, composite webs from polylactic acid (PLA) bicomponent fiber and natural fibers, cattail and kapok fibers, were prepared using the hot press method. Only the sheath region of the PLA bicomponent fiber melted, acting as an adhesive that enhanced the strength and reduced the thickness of the composite web compared with its state before hot pressing. The mechanical and physical properties of these composite webs were evaluated. Composite webs created from kapok fibers displayed a creamy yellowish-white color, while those made from cattail fibers showed a light yellowish-brown color. Additionally, the addition of natural fibers endowed the composite webs with hydrophobic properties. The maximum natural fiber content, at a ratio of 30:70 (natural fiber to PLA fiber), can be incorporated while maintaining proper water vapor permeability and mechanical properties. This nonwoven material presents an alternative with the potential to replace petroleum-based surgical gowns. [ABSTRACT FROM AUTHOR]

This study focuses on the increased risk of high heat release and asphyxiation (toxic gas poisoning) in the event of a fire involving polyurethane (PU)- and MDF-based building materials, which are commonly used in buildings. Among them, polyurethane (PU) building materials are very commonly used in buildings, except in Europe and some other countries, due to their excellent thermal insulation performance. Still, problems of short-term heat release and the spread of toxic gases in the event of a fire continue to occur. To overcome these problems, researchers are actively working on introducing various flame retardants into building materials. Therefore, in this study, we produced a laboratory-sized (500 mm × 500 mm) plate-like flame-retardant board that can be utilized as a building material with a lower heat release rate and a lower toxicity index. The material was made by mixing expanded graphite and ceramic binder as flame retardants in a material that is formulated based on the cellulose of waste paper, replacing the existing building materials with a hot-press method. According to the ISO-5660-1 test on the heat release rate of the plate-like flame-retardant board, the Total Heat Release (THR) value was 2.9 (MJ/m2) for 10 min, showing an effect of reducing the THR value by 36.3 (MJ/m2) compared to the THR value of 39.2 (MJ/m2) of the specimen made using only paper. In addition, the toxicity index of the flame-retardant board was checked through the NES (Naval Engineering Standards)-713 test. As a result, the test specimen showed a toxicity index of 0.7, which is 2.4 lower than the toxicity index of 3.1 of MDF, which is utilized as a conventional building material. Based on the results of this study, the cellulose fire-retardant board showed the effect of reducing the heat release rate and toxicity index of building materials in a building fire, which reduces the risk of rapid heat spread and smoke toxicity. This has the potential to improve the evacuation time (A-SET) of evacuees in fires. It is also important to show that recycling waste paper and utilizing it as the main material for building materials can be an alternative in terms of sustainable development. [ABSTRACT FROM AUTHOR]

Waste newspapers (WNPs), composed of mostly wood fibers and small amounts of inorganic fillers and printing ink, are a low-cost, abundant, and readily available form of household waste. Urea formaldehyde (UF) resin is used routinely to produce wood-based panel boards even though it releases harmful formaldehyde. The best way of resolving this issue is to use formaldehyde-free adhesives from renewable resources. Kraft lignin, a readily available, low-cost, and renewable waste product from the pulping industry, is used mainly as a fuel. Kraft lignin has good bonding ability to wood-based panel boards and improves water resistance. In this research, fiberboards were produced using a dry-processing method from recycled WNPs and bonded with kraft lignin instead of UF. The physical and mechanical properties of the produced fiberboards were evaluated. The results showed that the hot press temperature and kraft lignin content remarkably influenced the physical and mechanical properties of the fiberboards. As the hot press temperature and kraft lignin content increased, the overall performance of the fiberboards improved accordingly. The results indicate that WNPs could be a potential sustainable resource for fiberboards production.

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

In this work, MgAl 2 O 4 : Cr3+ transparent ceramics have been synthesized by the hot press sintering techniques, and the effect of the sintering aid Gd 2 O 3 and its content on the densification, microstructure, and optical, photoluminescence was studied and discussed. The relative density reached 99.29% with 0.8 wt% Gd 2 O 3 as a sintering aid, and the optical transmittance at 686 nm and 1446 nm were approximately 76%. As Gd 2 O 3 content continued to increase, the grain size of the ceramics became smaller and uniform, accompanied by some pores with the size of ～1 μm. The ceramics with 4.0 wt% Gd 2 O 3 showed a higher transmittance, of 82% at 1446 nm. Additionally, Gd 2 O 3 was helpful for Cr3+ in the sites of octahedral symmetry, which increased the quantum yield. The quantum yield of MgAl 2 O 4 : Cr3+ with 0.8 wt% Gd 2 O 3 was about 0.175, which was 36% higher than that of ceramic without Gd 2 O 3. In short, the sintering aid Gd 2 O 3 not only contributed to improving the densification, homogenizing the grain size, and heightening the optical transmittance but also enhanced the quantum yield of Cr3+. [ABSTRACT FROM AUTHOR]

In the present work, gadolinium-doped ceria-based powders were co-fired with additions of 1% (w /w) of SiO 2 , and 5% (w/w) of Y 2 O 3 to test the role of yttrium ion on improving the grain boundary conductivity across the grain boundary regions of low grade gadolinia-doped ceria (CGO) electrolytes. The samples were prepared by hot press at low temperature (1000 °C) to minimize bulk dissolution of yttrium in the CGO lattice. Structural characterization by XRD of the prepared ceramics confirms a CGO single phase material with the fluorite type structure. All the samples were characterized by impedance spectroscopy as a function of temperature in air, in order to de-convolute different microstructural contributions to the overall electrical behaviour. The results showed, as expected, that the presence of small amounts of impurity of silica reduces the total conductivity, when compared with pure CGO ceramic sample. The grain boundary resistance of these ceramics, under low operating temperatures, has a large effect on the total conductivity and is related, on one hand with the presence of a space charge layer created by the local segregation of trivalent rare earth elements, and the consequently depletion of oxygen vacancies, and on the other hand by the blocking effect of the silicon impurity. However, the obtained results show that addition of yttria increases total conductivity when compared with impure samples without yttria. This effect was related with the partial recover of specific grain boundary conductivity, suggesting a preferential location of Si and Y cations on grain boundaries. The space charge potential values, calculated using impedance data, provided an approach to the promoting effect of recovering grain boundary conductivity by the yttrium ion. • The use of low-grade raw materials for solid oxide fuel cells electrolytes. • Scavenge of silica impurities by yttria additions. • Electrical conductivity improvements by hoy press low temperature sintering. • Optimization of space charge and grain boundary conductivity. [ABSTRACT FROM AUTHOR]

The present study experimentally investigates tensile strength and impact toughness of plain composites made of carbon, glass, Kevlar, and steel wire mesh fabric; and hybrid composites of carbon-Kevlar reinforcement with polyethylene matrix. Composites are prepared by employing a hot press technique, where reinforcement fabrics, as well as polyethylene film are stacked in varying number of layers. Samples were cut from the composite plates for uniaxial tensile loading and low-velocity Charpy impact tests, as well as for resin burn-off process. It is shown that number of layers affects tensile and impact characteristics, as in general, tensile strength of composites increases with number of layers. Also, impact energy absorbed by the specimens is also proportional to number of layers. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

Ultra-thin high-density fiberboards (HDFs), a newly developed variety of fiberboards, broaden and extend the applications of medium thick medium- and high-density fiberboards and are capable of replacing cardboards for most applications. Old corrugated container (OCC) is an important packaging solid waste. The mechanical strength of OCC deteriorates after repeated recycling processes. Application of OCC fibers for value-added ultra-thin HDFs can be of much interest. Because the OCC fibers have more surface area than the wood particles, the resin coverage per surface area of the OCC is much lower than wood particles during panel board formation. Therefore, the performance of the OCC fiber-based board is poor and the resin adhesive consumption is high. To overcome these problems, a novel method of using OCC to make ultrathin HDFs was developed and investigated. In this work, the OCC was shredded and pulped before making the ultra-thin HDFs. To protect consumers from exposure to harmful formaldehyde, kraft lignin was used as a binder. The target density and thickness of the ultra-thin HDFs were 1.0 kg/m³ and 2 mm respectively. The resulting ultra-thin HDFs were evaluated for their physical and mechanical properties. Comparisons with the Chinese Standards for Wet-Process Fiberboards are presented. The results indicate that OCC could be a potential sustainable resource for ultra-thin HDFs production. [ABSTRACT FROM AUTHOR]

Natural silk non-woven fabrics from different silkworm varieties were fabricated on a large scale, and the influence of silkworm variety and process parameters upon the preparation, structure, and properties of the resulting non-woven was examined. In relation to productivity, the reel-ability of the silk cocoon was found to be strongly affected by the silkworm variety and the highest reeling length was achieved with the silk of Hanbyul. However, the influence of silkworm variety upon the crystallinity, morphology, porosity, moisture regain, and mechanical properties of the silk non-woven fabric was insignificant. Instead, the structure and properties of the silk non-woven fabric were more strongly influenced by the reeling bath temperature and hot press treatment. In detail, the reel-ability increased with increasing reeling bath temperature of up to 50 °C, thereafter remaining constant with further increase in temperature. Moreover, while showing a slight dependence on silkworm variety, the porosity, mechanical properties, and moisture regain of the fabrics were more strongly influenced by the press temperature. In conclusion, it was found that silk non-woven fabrics with various properties could be manufactured by careful selection of both the silkworm variety and the process parameters of reeling bath temperature and press temperature. [ABSTRACT FROM AUTHOR]

In this research, the silk web was hot-pressed for various times, the effect of press time on the structure and mechanical properties of silk non-woven fabric was also investigated. The yellowing appeared in the silk non-woven fabric and became more apparent as press time was increased. The crystallinity of silk was decreased by the hot press treatment and it did not change significantly with an increase of hot press time. The porosity of silk non-woven fabric was constantly decreased until 120 s and it did not change much after that. The thickness of silk non-woven fabric was significantly decreased by a press time of 10 s and slightly decreased with a further increase of hot press time. The hot press treatment increased the maximum stress and elongation of silk non-woven fabrics. The press time had a significant impact on the mechanical properties of silk non-woven fabric, with 90 s being the optimum condition for the best work of rupture of silk non-woven fabric. [ABSTRACT FROM AUTHOR]

Based on the problem of shape-preserving property of complex geometry shape preform, a kind of new fabric with thermal bonding layers was designed in our work. From the apparent view, it can be seen that the carbon cloth was attached with a layer of thermal bonding layer structure. The two adjacent carbon fabrics can be bonded together by the thermal bonding layers through hot press actions. Because of the particular characteristics, this type of fabrics can help to achieve the overall integrity of complex geometry shape preform. This kind of particular fabric with thermal bonding layers was prepared by 3D weaving process using carbon fiber and thermoplastic nylon fiber. To evaluate the effect of thermal bonding layers on shape-preserving property of fabric, the fabrics were prepared with five different contents of thermoplastic nylon fiber. And the pure carbon cloth without thermoplastic nylon fiber was also prepared as control group. The shape-preserving property of fabric was evaluated by single-wing springback test and fabric peeling test in the 0° and 90° direction. The experimental results show that the effect on shape-preserving property of fabric enhanced with the increase of contents of thermoplastic nylon fiber, and the shape-preserving property of fabric was more significant in 0° direction compared with 90° direction. [ABSTRACT FROM AUTHOR]

The high temperature gas-cooled reactors (HTGRs) are the next-generation reactors with high safety, because the cores of HTGRs would not melt. But it is important to improve the oxidation resistance of the fuel in case of a huge oxygen ingress into the core to further improve the safety of HTGRs, because most of the volume of the core of the HTGRs consists of graphite. Coated fuel particles (CFPs), of which the diameter is around 1 mm, are used in HTGRs. A small sphere containing fissile materials is sealed up with ceramics coating layers to form a CFP. A mixture of CFPs and starting materials of binding material (matrix) is sintered to form fuel compact. Currently the matrix is graphite, which would easily oxidized in case of a huge oxygen ingress into the core. In this study, the development of oxidation resistant fuel compact, of which the matrix is a mixture of SiC and graphite, has been carried out. Simulated CFPs (alumina particles) and starting materials of matrix (Si powder, graphite powder and resin) were molded and hot-pressed into simulated fuel compacts. In order to maintain the structural integrity of fuel elements for HTGR under accident conditions, not only oxidation-resistant but also high-strength fuel compacts should be further developed. Hot press conditions such as pressure would be one of the factors affecting the strength of the HTGR fuel elements. In order to identify the optimal hot press conditions for preparing the high-strength fuel elements, the effect of the hot press conditions on the mechanical strength properties of the HTGR fuel elements should be evaluated quantitatively. In the present study, the response surface model, which represents the relationship between the hot press conditions and the mechanical strength properties, has been constructed by introducing statistical design of experiments (DOE) approaches, and the optimal hot press conditions were estimated by the model.

In this article, we report a method for preparing high quality FeSe $_{1-x}$ Te $_x$ targets with tunable density using a high-pressure sintering process. The phase formation of the target is checked by X-ray diffraction. The targets show a single phase and can be indexed to a tetragonal structure with the space group of P4/nmm. Compared with the target prepared by the normally used solid-state reaction method, the density has been dramatically increased to 92.10% of the theoretical density. We also developed a more effective method of adjusting the density of the FeSe $_{1-x}$ Te $_x$ targets by changing the sintering temperature at a constant pressure. The preparation method of our FeSe $_{1-x}$ Te $_x$ target promises to provide an opportunity for the preparation of long coated conductors. [ABSTRACT FROM AUTHOR]

Abstract ᅟ We report on the successful preparation of Bi-doped n-type polycrystalline SnSe by hot-press method. We observed anisotropic transport properties due to the (h00) preferred orientation of grains along the pressing direction. The electrical conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 12.85 and 6.46 S cm−1 at 773 K for SnSe:Bi 8% sample, respectively, while thermal conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 0.81 and 0.60 W m−1 K−1 at 773 K for SnSe:Bi 8% sample, respectively. We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition, whose transition temperature increases with Bi concentration. Our work addressed a possibility to dope polycrystalline SnSe by a hot-pressing process, which may be applied to module applications. Highlights 1. We have successfully achieved Bi-doped n-type polycrystalline SnSe by the hot-press method. 2. We observed anisotropic transport properties due to the [h00] preferred orientation of grains along pressing direction. 3. We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition.

Facile patterning of electrodes is required for various electronic applications, particularly in solution-processed oxide thin-film transistors (TFTs). In this study, source and drain electrodes were prepared from silver nanowires (AgNWs) using spray-coating and hot press techniques. Although spray coating allowed production of AgNW patterns, which could function as electrodes in oxide TFT, the as-sprayed films did not provide a sufficient physical contact with oxide semiconductors and formed interspaces that impeded electron injection. At the same time, hot press technique produced denser AgNW networks that had a tight contact with the oxide semiconductors. As a result, hot-pressed films were considered as satisfactory source and drain electrodes for high-performance oxide TFTs, as they provided an easy electron injection. Finally, the prepared oxide TFTs with hot-pressed AgNW electrodes exhibited average field-effect mobility of 4.75 ± 1.5 cm2/V, significantly higher than that of the TFTs with as-sprayed AgNW electrodes (0.08 ± 0.05 cm2/V). Image 1 • Facile deposition of AgNW electrodes was suggested using spray and hot-press methods. • Hot press enabled to improve physical contact properties between AgNW and IGZO. • Top-contact IGZO transistors with hot-pressed AgNWs exhibited higher performances. [ABSTRACT FROM AUTHOR]

Electrode structure improvement is one of the most promising paths for improving the durability of polymer electrolyte membrane fuel cells (PEMFCs). As strategies to prevent structural deformation and enhance the durability of membrane electrode assemblies (MEAs) with structurally ordered PtCo/C-based cathodes, we evaluated the effect of hot pressing and reinforcing the electrode's structure by increasing the ionomer content. Even though the initial performances of the hot-pressed MEA (HP) and the MEA with extra cathode ionomer (EI) were lower than that of the conventional MEA (CE) by 13.6% and 19.1%, respectively, CE degraded much more significantly than HP and EI after an accelerated degradation test. Therefore, HP and EI could deliver significantly higher single cell performances than CE (22.7% and 43.7%, respectively). The improvements in the durability of HP and EI could be correlated with the structural stability which could be evaluated by structure and electrochemical analysis including electrochemical impedance spectroscopy. • Fabrication condition effect on polymer electrolyte membrane fuel cell was studied. • Hot pressing (HP) and extra ionomer (EI) improved durability. • Improved durability was due to facile mass transport after degradation of fuel cell. [ABSTRACT FROM AUTHOR]

Ta 2 O 5 nanoparticles were synthesized by thermal decomposition of tantalum (V) ethoxide, and Ca 3 Co 4 O 9 /Ta 2 O 5 composites were fabricated by ball milling. The volume percentage of Ta 2 O 5 nanoparticles in the composites was controlled as 0, 2%, 4%, and 6% in four samples. The existence and dispersion of Ta 2 O 5 nanoparticles in the composites were confirmed by electron microscopies. The Ca 3 Co 4 O 9 /Ta 2 O 5 composite particles were hot-pressed into pellets and sintered for thermoelectric property measurement. The impacts of the Ta 2 O 5 volume percentage on the lattice/electronic thermal conductivity, Seebeck coefficient, electrical conductivity, and thermoelectric Figure of Merit (ZT) of the Ca 3 Co 4 O 9 /Ta 2 O 5 composites were investigated. The results indicated that an increased Ta 2 O 5 volume percentage resulted in decreased electrical conductivity and thermal conductivity. When the Ta 2 O 5 was 4 vol %, the highest Seebeck coefficient, and maximum ZT were observed in the Ca 3 Co 4 O 9 /Ta 2 O 5 composite. [ABSTRACT FROM AUTHOR]

The present study deals with the development and characterization of a Mo-Ti-Si alloy by pressure-assisted sintering for high-temperature applications. The three-phase alloy was found to be consisted of (Mo,Ti)3Si-type silicide and discontinuous Mo-rich and Ti-rich α-(Mo, Ti)ss phases. The alloy was characterized for mechanical properties, creep, and wear behavior. Elastic modulus and hardness of all the constituent phases were determined using nanoindentation technique. Creep properties of the alloy determined from the compression creep tests in vacuum were found to be better than the single-phase Mo5Si3 and Ti5Si3 at the tested temperature of 1000 °C. The coefficient of friction values were found to be 0.59, 0.55 and 0.4 at the testing loads of 10, 15 and 20 N, respectively, at 10 Hz frequency in reciprocal testing mode at room temperature, while 0.42 at 500 °C with a load of 15 N. The dominant wear mechanism was proposed based on the wear scar analysis. [ABSTRACT FROM AUTHOR]

The influence of moisture content was investigated relative to the pellet forming process and the pellet properties. Three different types of raw biomass (pine sawdust, corn straw, and peanut shell) were pelletized by hot pressing at different moisture levels (12%, 14%, and 16%) in a pellet mill with horizontal and ring type dies to investigate its physical property indexes of durability, pellet density, and combustion performance. The results of the study showed that pellet density and heating value were related to the moisture content. The maximum pellet density of the fuel pellets of sawdust, corn straw, and peanut shells was 1180 kg/m³, 1220 kg/m³, and 1130 kg/m³, respectively. The drop resistance and deformation resistance of pine sawdust and corn straw decreased with increased moisture content, but peanut shell initially increased with the increase of moisture before decreasing. The comprehensive combustion index of corn straw (14.03) was the highest during the combustion performance analysis in comparison to sawdust (11.10) and peanut shell (10.00). Overall, the optimal moisture content of sawdust, corn straw, and peanut shell was 12%, 12%, and 14%, respectively, and the combustion performance of the pellets made from corn straw was superior compared to the other two feedstocks. [ABSTRACT FROM AUTHOR]

Taking the nano precusor powder of fluorapatite and nano powder of fluorophlogopite prepared by liquid method as raw material, the fluorphlogopite/ fluorapatite biological glass-ceramic was prepared by hot pressed technology in vacuum sintering furnace. The crystallization behaviors,crystalline phases, microstructures and mechanical behavior of the glass-ceramics were investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results reveal that under certain sintering process, the crystallity of the glass-ceramic is improved obviously. With the increasing of fluorapatite mass-fraction, the porosity of the glass ceramic is decreased significantly, and the bending strength and micro-hardness are improved gradually. The good performance of the glass-ceramic is attributed to the characteristic structure of fluorapatite. [ABSTRACT FROM AUTHOR]

• Relatively higher density was achieved for hot pressed Cu and Cu-15Al alloy. • The hardness of Cu was significantly improved with the addition of Al. • Drastic reduction in corrosion of Cu with addition of 15 wt% Al. • The formation of protective layer improved corrosion resistance of Cu-15Al alloy. Higher density of 98.66 and 94.60% ρ th (theoretical density) was achieved for hot pressed Cu and Cu-15Al alloy, respectively. The microstructure of Cu-15Al alloy consists of α (Cu 0.78 Al 0.22) and γ 2 (Cu 9 Al 4) phases. The hardness of Cu was significantly improved (from 1.32 to 6.03 GPa) with the addition of Al. Drastic reduction in corrosion of Cu-15Al (1.6 mpy) when compared to pure Cu (20.7 mpy) was noticed despite the low densification of Cu-Al. The higher impedance of Cu-15Al alloy corroborates the formation of protective layer. This work demonstrates the efficacy of high amount of Al in improving corrosion resistance of Cu. [ABSTRACT FROM AUTHOR]

Abstract We investigated he thermoelectric (TE) properties and microstructures of Na-doped PbTe compounds, synthesized by various milling and sintering processes. It has been generally accepted that spark plasma sintering (SPS) inhibits grain growth due to the short sintering time, which is beneficial to the nano bulk composite. In contrast, we observed abnormal grain growth for SPS, unlike hot press (HP) sintering. Considering the Gibbs free energy change during sintering, the HP sintering increases internal energy while the SPS increases entropy energy, which causes the abnormal grain growth. Lattice strain and Fourier transform analyses of the transmission electron microscope images showed that the SPS sintered samples had more significant lattice strains and defects than the HP sintered samples. The low thermal conductivity of the SPS sintered samples was not from grain boundary phonon scattering but from phonon scattering by lattice strains and defects. The lattice strains and defects decreased electrical conductivity as well, resulting in deterioration of the power factor and thermoelectric performance. This suggests that the lattice strains and defects are more critical factors for enhancing thermoelectric performance than particle and grain size control. Highlights • Abnormal grain growth driven by entropy energy change is significant in spark plasma sintering. • SPS sintered samples have more significant lattice strains and defects than those of hot press. • Phonon scattering by lattice strains and defects decreases lattice thermal conductivity in SPS. • The lattice strains and defects decreases electrical conductivity as well. [ABSTRACT FROM AUTHOR]

In this study, effect of nano-wollastonite on fire resistance characteristics of wood flour/polypropylene composite was investigated. The composites samples were manufactured using a dry blend/hot press method. In this study, the dried wood flour of beech as the filler in a 60%, poly propylene as the matrix in a 37% and polyethylene grafted with maleic anhydride as the coupling agent in a 3% total weight was used. Also, nano-wollastonite was used in four levels of dried wood flour loading (0, 1, 3 and 5%). Nominal density and dimensions of the composites were 1 g/cm3 and 1*20*25 cm, respectively.Bending strenght according to ASTM standard and Fire resistance characteristics such as, flammability duration, duration of flame after removing the burner, duration of glow after removing the burner and mass reduction were measured acceding to ISO 11925. Results indicated that by increasing the nano-wollastonite increases the bending strengh,MOE and flammability duration increased but mass reduction, duration of flame and duration of glow decreased. Also the dispersion of nano-wollastonite in composites was evaluated by Filed Emission Scanning Electron Microscopy (FE-SEM).

The applications of pure multi-walled carbon nanotubes (MWCNTs) buckypapers are still limited due to their unavoidable micro/nano-sized pores structures. In this work, polyvinyl alcohol (PVA) was added to a uniform MWCNTs suspension to form MWCNT/PVA buckypapers by vacuum infiltration combined with a hot press method. The results showed an improvement in the thermal, electrical, and electromagnetic interference (EMI) shielding properties due to the formation of dense MWCNTs networks. The thermal and electrical properties rose from 1.394 W/m·k to 2.473 W/m·k and 463.5 S/m to 714.3 S/m, respectively. The EMI performance reached 27.08 dB. On the other hand, ABAQUS finite element software was used to simulate the coupled temperature-displacement performance. The electronic component module with buckypapers revealed a homogeneous temperature and thermal stress distribution. In sum, the proposed method looks promising for the easy preparation of multi-functional nanocomposites at low-cost.

Abstract In this work, hot press and hot deformation were applied to p -type Bi 2-x Sb x Te 3 (x = 1.5–1.8) starting powders that have not undergone nanostructuring processing. The effects of hot pressing and hot deformation, as well as Sb-alloying, on the microstructure and the thermoelectric properties of the Bi 2-x Sb x Te 3 alloys were systematically investigated. The results of this study are compared to those of others, which have addressed similar issues in samples prepared with analogous compaction techniques. ZT value of 1.12 at 375 K for hot pressed Bi 0.4 Sb 1.6 Te 3 and ZT value of 1.24 at 375 K for hot deformed Bi 0.4 Sb 1.6 Te 3 were achieved. To our knowledge, the latter ZT value is only slightly lower than the highest ever reported (ZT~1.3) for p-type bismuth telluride-based alloys prepared using starting materials without nanostructuring, suggesting that simpler preparation techniques can be applicable in modules fabrication. Graphical abstract Temperature dependence of the in-plane dimensionless thermoelectric figure of merit ZT for hot pressed (HP) and hot deformed (HD) Bi 2-x Sb x Te 3 samples (x = 1.5–1.8) prepared using powders that have not undergone nanostructuring processing. Data from Hu et al. are also included for comparison. fx1 Highlights • High ZT Bi 2-x Sb x Te 3 alloys are obtained using non-nanostructured starting materials. • Hot pressed and hot deformed samples have an average ZT of 1 and 1.15, respectively. • All thermoelectric properties have been measured in the same in-plane direction. • A low Lotgering factor is not a good criterion to treat Bi 2-x Sb x Te 3 samples as isotropic. [ABSTRACT FROM AUTHOR]

The main objective of our work is to increase transmittance in the mid infrared region by removing impurities through the pre-heating treatment of zinc sulfide (ZnS) produced by hydrothermal synthesis. The pre-heating treatment proceeded at 450 to 600 °C for 2 h under vacuum atmosphere (10−2 Torr). It was confirmed that the particle size increased as the pre-heating temperature increased. Additionally, all ZnS nano powders had a sphalerite (cubic) structure unaffected by pre-heating treatment. The ZnS nano powders were sintered by hot-press sintering method. As the pre-heating temperature increased, transmittance was improved due to the decreasing of porosity, increase of particle size, and the removal of impurities (carbon and sulfate). However, when the pre-heating treatment temperature was 600 °C, the transmittance slightly decreased due to the formation of a hexagonal phase. The ZnS ceramic with pre-heating treatment at 550 °C showed the highest transmittance (71.6%) and density (99.9%). [ABSTRACT FROM AUTHOR]

Abstract In this study, hot-pressing technique was used to produce Al-5wt.% Cu-20vol.% SiC and Al-5wt.% Mg-20vol.% SiC particulate metal matrix composites. The powders were ball milled and the powder mixtures were hot pressed uniaxially under a pressure of 550 MPa at a temperature of 450 °C in vacuum atmosphere for different holding times of 30, 60 and 120 min. A common observation was that the density of Al composites decreased slightly with increasing hot press sintering time. The Al-5wt.% Cu-20vol.% SiC samples exhibited maximum density of ∼95.7% ρ th (theoretical density) and Al-5wt.% Mg-20vol.% SiC composite was measured with maximum density of ∼97.8% ρ th after hot pressing for 30 min. The XRD and SEM characterization confirms presence of Al, SiC and CuAl 2 phases for Al-Cu-SiC. Whereas the microstructure of Al-Mg-SiC composite consists of Al 0.95 Mg 0.05 solid solution phase along with SiC phase. Among all the compositions, a maximum hardness of 3.2 GPa was noted for the Al composites, which were hot pressed at 60 min. A comparison with the existing literature reveals the presently developed Al alloy composites exhibited superior hardness. Corrosion tests were carried out using potentiodynamic polarization and electrochemical impedance spectroscopy to study the corrosion behavior of both these hard composites in marine environment (3.5wt.% NaCl) at room temperature. The corrosion rate of the samples varied between 1.8 and 2.7 mpy (mils per year), particularly, Al-5wt.% Cu-20vol.% SiC composite showed better corrosion resistance. Further impedance spectroscopy analysis revealed that Al-Cu-SiC has relatively larger semi-circular diameter when compared to Al-Mg-SiC. These observations indicate that Al-Cu-SiC exhibits high polarization resistance than Al-Mg-SiC composite. Highlights • The hot pressed Al composites could be highly densified (more than 95% theoretical density). • A maximum hardness of 3.2 GPa was noted for the Al composites. • Al-Cu-SiC composite exhibited better corrosion resistance than Al-Mg-SiC. [ABSTRACT FROM AUTHOR]

Commercial success for proton exchange membrane fuel cell (PEMFC) requires manufacturing of its core component, membrane electrode assembly (MEA), with consistent and reliable performance. In this study, three common methods for the MEA manufacturing are investigated systematically for their impact on the cell performance under consistent preparation and cell test conditions, including catalyst coated substrate (CCS), catalyst coated membrane (CCM), and low temperature decal method (LTDM). The variations in each of these methods studied include applying an extra Nafion layer, hot press, and Pt loading. It is found that MEA manufacturing process has a significant impact on the cell performance, and this impact is significantly affected by the Pt loading. At the high Pt loading of 0.5 mg/cm 2 , CCM without hot press involving gas diffusion layers (GDLs), referred to as CCM-Wo, results in the best performance with the maximum power density of 0.95 W/cm 2 , although both LTDM and CCS with an extra Nafion layer (hence called N-LTDM and N-CCS) are just slightly less with the maximum power density of 0.91 W/cm 2 . Hot press with GDLs is essential for CCS method to achieve a good performance, while it is not the case for CCM and N-LTDM. Applying an extra layer of Nafion on catalyst layers as in N-LTDM and N-CCS methods has a positive impact on the cell performance; whereas it is negative when it is applied on the membrane as in the N-CCM method. When the Pt loading is reduced to 0.125 mg/cm 2 (75% reduction in the Pt loading), cell performance is reduced for all the MEAs made by the three methods, but significant reduction (about 75%) is observed for CCS method, while it is less than 30% for the other two methods. Therefore, care should be taken in the MEA manufacturing for MEAs with low Pt loadings. [ABSTRACT FROM AUTHOR]

This paper studies the microstructure and mechanical properties of hot pressed submicron TiB 2 powders obtained from a special carbon coated precursors method. With the hot press temperature increasing from 1500 °C to 1800 °C, the relative density increases and the sample maintains a single TiB 2 phase. The powders are able to be sintered to a relative density of ~94.5% at the temperature of 1800 °C. For the first time, unique elongated platelike grain structure, which has only been observed from transient liquid phase or reaction sintered borides, also forms at the sintering temperature of 1800 °C. In addition, the sample sintered at 1800 °C has a fine microstructure (elongated grain of ~0.3–3 µm) and high mechanical properties (hardness of ~27.6 ± 2.3 GPa, flexural strength of ~560 ± 49 MPa, and fracture toughness of ~6.5 ± 0.2 MPa m −1/2 ). Correlations between mechanical properties and microstructure are further discussed. [ABSTRACT FROM AUTHOR]