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Perovskites, known for their excellent photoluminescence efficiency and color purity, have seen widespread application in flat panel displays and lighting in recent years. Here, we present a process for fabricating CsPbBr3 perovskite film (PeFilm) with high luminescent properties and remarkable weather resistance. By combining single-source vapor deposition (SSVD) with subsequent heat treatment, the quality of PeFilms has been significantly improved. We enhanced the quality of PeFilms by using a thermal annealing process to remove PbBr2 from CsPb2Br5. During annealing, PbBr2 evaporates from PeFilms, changing the crystal phase to CsPbBr3. The heat treatment rearranges atoms between grains, promoting grain growth and fusion, producing larger crystals and reducing defects. The research results demonstrate that the integration of SSVD and appropriate heat treatment enables the fabrication of the CsPbBr3 PeFilm with an emission wavelength of 533 nm, CIE coordinates of (0.1842, 0.7797), and a photoluminescence quantum yield (PLQY) of 52.1%, and even after storing it in atmospheric conditions for 100 days, the PLQY of the CsPbBr3 PeFilm remains above 52%, demonstrating excellent stability. [ABSTRACT FROM AUTHOR]

In this study, a TiNbCrTa refractory complex concentrated alloy (RCCA) was prepared using vacuum arc remelting. The microstructural evolution and mechanical properties of both as-cast and heat-treated RCCA samples were analyzed. Heat treatment (HT) was performed at 800–1200 °C for 1 h in a vacuum-sealed environment. These samples exhibited a formation of Cr2Nb and Cr2Ti Laves phases. A variation in elemental distribution was observed, with interdendritic (ID) regions showing higher fractions of Ti and Cr, while the dendritic regions had a greater concentration of Ta and Nb. Micro-segregation at the IDs was confirmed through energy dispersive x-ray spectroscopy mapping, which inferred the formation of Cr- and Ti-rich phases during HT at 800–1200 °C. High-temperature HT at 1200 °C for 1 h led to the evolution of the hcp omega phase. Prolonged HT at 1200 °C for 96 h resulted in the evolution of a Cr-rich Laves phase (Cr2Ta), which was homogeneously distributed within the microstructure, indicating an unstable microstructure. Furthermore, despite prolonged HT, a variation in the elemental distribution persisted due to the presence of dendritic and ID regions. Electron backscattered diffraction analysis revealed the presence of bcc and hcp phases in the dendritic and ID regions, respectively, of the as-cast and HTed samples. The as-cast samples demonstrated a high compressive strength of approximately 2 GPa. Micro-hardness values increased with the HT temperature up to 1000 °C. Further increases under HT conditions did not significantly reduce the microhardness value, whereas prolonged HT at 1200 °C led to an increase in the microhardness value. Overall, the newly developed TiNbCrTa RCCA exhibited high-strength behavior even after the phase transformation. [ABSTRACT FROM AUTHOR]

In this work, we studied the nature and dilemma of the inverse magnetocaloric effect using Ni50Mn36In14 magnetic shape memory alloy. In this context, the inverse magnetocaloric effects of Ni50Mn36In14 magnetic shape memory alloy polycrystalline samples were investigated as a function of annealing heat treatments by the thermo-magnetometry method. Two forms of Ni49TiMn36In14 magnetic shape memory alloy were studied: one that predominantly undergoes a magnetic phase transition and the other that exhibits both a magnetic and martensitic phase transition. The magnetic behaviors and magnetocaloric properties of these alloys were analyzed to investigate the competition between magnetic and lattice contributions to the total entropy change. Finally, the mutually contradictory role of magnetic and lattice contributions was demonstrated. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have attracted widespread attention from scholars as a new type of material employed in extreme environments. However, as a main kind of HEAs, many face-centered cubic single-phase HEAs are restricted in industrial applications due to their lower yield strength and high cost when containing expensive elements such as Co. In this study, dispersion strengthening by heat treatment was introduced in low-cost Co-free Fe40Mn20Cr20Ni20 HEA to improve its strength, and its high-temperature tensile behavior and constitutive model were studied to explore its potential application at high temperatures. It is found that when subjected to quasi-static room-temperature stretching, the heat-treated sample exhibits a yield strength of 534 MPa and a tensile plasticity of 26.8%. In addition, the tensile behavior of samples after heat treatment was investigated at high temperature (573–873 K) and low strain rate (10−3–10−1 s−1). The results suggest that the yield strength decreases with increasing temperature and decreasing strain rate. Moreover, at 873 K and 10−3 s−1, the electron backscatter diffraction system and x-ray diffraction results of the deformed sample indicate that the softening curve is driven from the recovery of materials. Finally, the flow stress was predicted using the Arrhenius equation and Artificial Neural Network model (ANN), and the two models were assessed using the average absolute relative error and coefficient of correlation (R). The results showed that the ANN had higher accuracy. [ABSTRACT FROM AUTHOR]

Spherical powders are required for many advanced manufacturing techniques due to their inherent requirement of flowability, either within feed tubes or during powder spreading. As advanced manufacturing of magnets continues to develop, new production methods for feedstocks are also sought. Plasma spheroidization is a high-yield method to produce spherical Nd–Fe–B powders from irregularly shaped particles, with advantages including high throughput and a well-controlled size distribution. Highly spherical Nd–Fe–B powders with large scale production (i.e., kg) have been demonstrated using an inductively coupled thermal plasma system; however, the magnetic properties of the output powder display significant degradation. The coercivity was decreased from the initial 8 kOe (636 kA/m) of the as-received to 0.7 kOe (55 kA/m) for spheroidized powders. Microstructural investigation reveals 6% Nd depletion caused by the extreme temperatures of the plasma, leading to the formation of low-coercivity α-Fe and a subsequent decrease in energy product. Post-spheroidization heat treatments with Nd can partially mitigate the coercivity degradation, increasing to 1.7 kOe (135 kA/m), potentially offering a pathway toward spherical powders for a range of applications. [ABSTRACT FROM AUTHOR]

Theoretical and experimental approaches have been employed for studying the lattice site occupation effect on the electronic structure and some physical properties of CoMnCrAl Heusler alloy (HA). Among possible variants of the ordered stoichiometric CoMnCrAl HA lattice site occupation by Co, Mn, Cr, and Al atoms, the first-principle calculations have been performed for three nonequivalent ones (marked by us as type 1, type 2, and type 3, respectively). CoMnCrAl HA with atomic order of the first type is half-metallic ferromagnet (FM) with resulting magnetic moment of m t o t 1 = 0.9999 μ B /f.u. and spin-polarization degree of Fermi electrons P 1 = 100 % , for atomic orders of second and third types, m t o t and P are equal to m t o t 2 = 1.0186 μ B /f.u., P 2 = 89 % and m t o t 3 = 6.8673 μ B /f.u., P 3 = 77 % , respectively. Changes in the order type on the way T1 → T2 → T3 cause a decrease in the spatial electron density, weakening of the covalent chemical interatomic bonds, lead to a decrease in the cohesion energy E c o h and hence to loss of the thermodynamic stability of the CoMnCrAl alloy. Despite various high-temperature heat treatments, only B2- and A2-types of atomic order have been obtained in bulk and film CoMnCrAl alloy samples. Experimentally, it was found that bulk B2-type ordered CoMnCrAl alloy demonstrates significantly lower magnetization [ M (300 K) = 0.442 μ B /f.u.] and spin-polarization degree of Fermi electrons [ P ≈ 30 % ] than theoretically predicted. More disordered crystalline CoMnCrAl films with A2-type of atomic order practically are non-FM at T = 300 K with P = 0. [ABSTRACT FROM AUTHOR]

In the present work, we study the effect of quenching and annealing on the ferroelectric and piezoelectric properties at room temperature and elevated temperatures of a new ternary BiFeO3-PbTiO3-Li0.5Bi0.5TiO3 bulk piezo ceramic. While sacrificing part of the maximally obtainable piezoelectric constant value, using an optimal heat treatment, a quasi-stable value for the piezoelectric constant of 65 pC/N was obtained irrespective of the annealing temperature. All experimental results point to the direction of unusual defect behavior in this novel ternary system leading to a well-defined metastable state. The quenching and annealing process are completely reversible and can be used in combination with additional chemical modifications to tailor the properties of this new high-temperature piezoelectric ceramic to the intended use conditions. [ABSTRACT FROM AUTHOR]

[This corrects the article DOI: 10.3389/fnut.2022.926814.].

In this study, ZrB 2 -SiC-ZrC (ZSZ) composite powders with molar ratios C/(B + Zr + Si) = 1.5, 1.9 and 2.4 were obtained by sol-gel method and boro/carbothermal reduction reaction. Meanwhile, the impact of heat treatment temperature (1100 °C–1600 °C) and holding time (1 h–2.5 h) on the resulting powders were studied. The results showed that the ZSZ powder precursors were first completely converted to ZrO 2 , SiO 2 , B 2 O 3 and pyrolytic carbon after heat treatment at 1200 °C under the optimized molar ratio (2.4) and holding time (2.5 h). Then, the transformed oxidation products and pyrolytic carbon were completely transformed into ZSZ composite powders after optimized heat treatment at 1500 °C. The synthesized ZSZ composite powders are characterized by the core-shell structure, in which ZSZ particles act as the inner core are encapsulated by the low-crystalline ZrB 2 phase as the outer shell to form a core shell structure. The ZSZ composite ceramic materials prepared using the core-shell structural powders have excellent ablative properties in the range of 2000 °C, with the mass and line ablation rate of −3.5 × 10−4 g/cm3 and 2.39 × 10−3 mm/s, respectively. [ABSTRACT FROM AUTHOR]

A nanocrystalline textured stainless steel (SS) surface passivated with an AlCr oxide layer is proposed for use as a high temperature solar selective absorbers (SSAs). The textured SS surface was prepared by oxidizing in air at 800 °C for 30 min. The heating resulted in outward diffusion of the SS substrate Mn atoms, their oxidation on the surface, and formation of octahedral Mn 3 O 4 nanocrystals, which play a role of textured surface. The passivation AlCr oxide single layer was deposited on the textured surface using reactive RF magnetron sputtering to protect the SS from further oxidation. The solar absorptivity α s and thermal emissivity ε 298K of the as-deposited SSAs were 0.84 and 0.165, respectively. In order to study high temperature stability, SSAs were heat treated under air conditions at 600–900 °C for 0.1–300 h. SSAs demonstrated thermal stability at 600 °C for at least 300 h and degradation of optical properties with performance criterion PC < 0.05 at 700, 800, and 900 °C for 300 h, 30 h, and 1 h, respectively. The increase in thickness of the surface Cr 2 O 3 layer on SS substrate was identified as the main degradation mechanism of SSA optical performance. SSAs demonstrated a high activation energy of 330 ± 30 kJ/mol. The obtained data can be used to design high temperature SSAs for concentrating solar energy systems operating under vacuum or air conditions at 500 °C. [ABSTRACT FROM AUTHOR]

Spinel saggar was prepared using Magnesium Aluminum spinel (MgAl 2 O 4), KF and TiO 2 as primary raw materials. The saggar's toughness was enhanced through in-situ generation of potassium titanate whisker (PTW). The impact of sintering temperature on the saggar's phase composition, whisker growth and physical properties was investigated. The findings indicated that the spinel saggar exhibited high densities and robust mechanical strength following heat treatment at 800 °C for 3 h, with an apparent porosity of 27.9 %. The cold modulus of rupture (CMOR) and cold crushing strength (CCS) were measured at 5.58 MPa and 21.05 MPa, respectively. The saggar retained rate 75.6 % of their strength after three thermal cycles at 800 °C for 20 min followed by air cooling. Corrosion analysis identified LiAlO 2 as the primary corrosion product of the spinel saggar. PTW facilitated particle bonding, enhancing the strength and toughness of the spinel saggar. This promoted the dispersion and absorption of thermal stresses during cyclic corrosion to prevent further damage. In contrast, for cordierite-mullite saggar corrosion products included LiAlO 2 , eucryptite(β-LiAlSiO 4) and Li 4 SiO 4. The disparate thermal expansion among these phases resulted in the formation of through cracks, exacerbating saggar corrosion damage. The spinel saggar demonstrated superior performance during the cyclic corrosion process. [ABSTRACT FROM AUTHOR]

High-entropy carbides-SiC biphasic ceramics demonstrate outstanding mechanical and oxidation resistance properties. However, previous studies have predominantly focused on fabricating dense monolithic high-entropy carbides-SiC biphasic ceramics, with limited attention given to the production of high-purity, narrow particles size distribution high-entropy carbides-SiC biphasic ceramic powders. In this study, we successfully synthesized high-entropy carbides-SiC biphasic ceramic powders, specifically (Hf 0.25 Zr 0.25 Ta 0.25 Ti 0.25)C-SiC, utilizing the polymer-derived-ceramic (PDC) route employing transition metal alcohol solution and methyltrimethoxysilane. The resultant powders exhibited an average particle size of ∼15 μm, with a narrow particle size distribution. Furthermore, variations in the heat treatment temperature demonstrated minimal impact on the particle size, while maintain compositional homogenous from nanoscale to microscale, and exhibiting low oxygen content less than 1.01 %. The introduction of the SiC phase also enhances the dynamic oxidation resistance of the high-entropy carbides. This pioneering work will not only provide a novel approach for obtaining other high-entropy carbides and SiC biphasic ceramic powder but also offers prospects for large-scale fabrication in industrial. [ABSTRACT FROM AUTHOR]

A CO 2 -stable, easily sintered proton-conducting oxide electrolytes based on solid solution Ba 7 In 6 Al 2– x Zn x O 19-0.5 x with hexagonal structure has been synthesized for the first time. Within the homogeneity region (0 ≤ x ≤ 0.10), there is an increase in unit cell parameters, cell volumes and free cell volumes. The addition of Zn2+ markedly improved the sinterability of the material. The relative density of the ceramics of the doped samples reached 95 % at lower sintering temperatures than the parent phase. The electrical conductivity was studied using electrochemical impedance spectroscopy. Upon doping the oxygen-ion conductivity increased by 0.25 orders of magnitude at 800 °C. Proton transport was predominant below 500 °C for a wet atmosphere (pH 2 O = 1.92·10−2 atm). The investigated phases Ba 7 In 6 Al 2– x Zn x O 19-0.5 x are capable of hydration and incorporate up to 1.45 mol H 2 O vs 0.41 mol H 2 O for the parent phase. The studied phases exhibit chemical resistance to CO 2 under heat treatment at 600 °C. It was shown that solid solution Ba 7 In 6 Al 2– x Zn x O 19-0.5 x is a promising electrolyte material for intermediate-temperature fuel cells. [Display omitted] • The Zn-doping in solid solution Ba 7 In 6 Al 2– x Zn x O 19-0.5 x markedly improved the sinterability of the material and well-sintered ceramics were obtained with relative density 95 %. • The water uptake increased with increasing Zn-concentration. • Ba 7 In 6 Al 2– x Zn x O 19-0.5 x phases were protonic conductors at T < 500 °C in wet air. • Ba 7 In 6 Al 2– x Zn x O 19-0.5 x phases exhibited chemical resistance to pure CO 2. [ABSTRACT FROM AUTHOR]

The use of graded-index (GRIN) lenses in infrared imaging systems is an effective way to reduce system volume. Chalcogenide glass has been considered an ideal matrix material to produce infrared GRIN lenes because of its excellent rheological property and large refractive index (RI) tunability. Herein, an axial GRIN Ge-As-Se-Te chalcogenide glass with large RI contrast (Δn) was designed and prepared. The GRIN glass was obtained by hot-pressing 11 stacked glass disks with gradually changing RIs and thermally treating them. The glass compositions of the disks were designed according to (1-x) (Ge 20 As 20 Se 20 Te 40)-xGe 12 As 22 Se 66 , where x = 0–1. It was found that these glasses had similar glass transition temperatures of 194∼199 °C, and excellent anti-crystallization performance. The RI (at 10 μm) of the glass dropped approximately linearly from 3.050 to 2.566 as x increased from 0 to 1. More than 1.2 mm diffusion depth was observed on hot-pressed two-layer glass preforms after only 24-h heat treatment. A GRIN glass with a thickness of ∼4.3 mm and linear RI profile was achieved by treating a hot-pressed eleven-layer glass preform for 24 h. The obtained GRIN glass showed good transmittance in the 3–12 μm wavelength range. These results indicate good prospects of the GRIN Ge-As-Se-Te glass for infrared imaging. [ABSTRACT FROM AUTHOR]

Fluorapatite glass-ceramics were prepared at lower temperatures by atmospheric pressure sintering method using KF, MgF 2 and CaF 2 as additives, respectively. Using XRD, SEM and mechanical property test to justify the effect of different fluorides on the sintering properties of fluorapatite composites. The results show that fluoride can be used as nucleating agent, react with wollastonite and phosphate glass to crystallize rod-like fluorapatite phase during heat treatment. The crystallization mechanism of fluorine-containing glass-ceramics was analyzed by crystallization thermodynamics and crystallization kinetics. KF with lower melting point is beneficial to promote the crystallization reaction and improve the morphology stability of the glass ceramic composite, but the volatile gas released during the reaction will affect the mechanical properties of it, resulting in a flexural strength of only 11.81 MPa at 900 °C. For the samples supplemented with MgF 2 and CaF 2 , because of the formation of polycrystalline phase systems, the flexural strength of the composite at 900 °C increases to 62.79 and 52.6 MPa, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, Eu3+ doped multi-component transparent aluminosilicate and oxyfluoride aluminosilicate glasses were fabricated by the melt-quenching procedure, and the glass-ceramics containing LiAlSi 2 O 6 microcrystals (LAS glass-ceramics) were produced by a two-step heat treatment process. The XRD, SEM, and EDS data demonstrate that spherical single-phase LiAlSi 2 O 6 microcrystals have precipitated from the glass matrices. The microhardness and flexural strength of the glass-ceramics vary in 6.27–6.66 GPa and 89.18–155.75 MPa, respectively. Phonon sideband analysis reveals that the phonon energies for both fluorine-containing and fluorine-free LAS glass-ceramics are approximately 971 cm−1, and the multiphonon relaxation rates (W mp / W 0) of the former are lower than those of the latter. Given its lower W mp / W 0 values, the fluorine-containing LAS glass-ceramic exhibits a higher emission intensity and a longer lifetime. Under 394 nm excitation, the fluorine-containing LAS glass-ceramic presents a warm and nearly pure red emission, characterized by a correlated color temperature of less than 3300 K and a color purity approaching 100 %. Time-resolved emission spectra support the photoluminescent stability of the Eu3+ ions. According to the Judd-Ofelt theory and spectral results, the fluorine-containing LAS glass-ceramic possesses lower Ω 2 / Ω 4 and asymmetry ratios, leading to a more symmetrical local environment for the Eu3+ ions. Benefiting from its enhanced red emission, the 5D 0 →7F 2 transition in the fluorine-containing LAS glass-ceramic exhibits a higher branching ratio (69.28 % > 50 %), emission cross-section (8.94 × 10−22 cm2), and gain bandwidth (12.12 × 10−28 cm3). Additionally, temperature-dependent photoluminescence spectra substantiate the excellent thermal stability of the Eu3+ doped fluorine-containing LAS glass-ceramic. Specifically, the intensity of the 5D 0 →7F 2 transition at 150 °C remains 80 % of the initial intensity. Therefore, the Eu3+ doped multi-component transparent oxyfluoride aluminosilicate glass-ceramic has a significant competitive advantage in the field of red lasers and trichromatic WLEDs. [ABSTRACT FROM AUTHOR]

The study aimed to look at the differences between a high entropy alloy and a dual phase high entropy alloy with high iron and Mn content. It also wanted to find out what happened when a small amount of the rare earth element erbium oxide (Er 2 O 3) was added to these alloys, especially on the mechanical and microstructure of the alloy. The first step in this study was to get 99 % pure metal powders, which were then made by dividing the powders into 30 g of equal weight. The powders were mixed evenly and then pressed into 10-g blocks under 6 tons of pressure. They were then set up to be melted in an arc. Four of the eight samples that were melted in an arc under vacuum were treated with heat. The four different compositions were then turned into small metallographic samples for SEM, EDX, Mapping, XRD, and microhardness tests. The study's imaging and analysis processes were also carried out. After that, SEM images were taken at various magnifications (100X, 500X, 1000X, 2500X, and 5000X), and EDS and XRD analyses were done on different structures found in these images. These analyses were based on literature research about the clarity of the metallographic images in the alloy, which showed the study's metallographic differences. The samples were put through microhardness and wear tests to see which one was stronger and less worn. The dual phase high entropy alloy (A2) was stronger and less worn than the high entropy alloy (A1). Er 2 O 3 had little effect on the alloys' mechanical properties or microstructure. The heat treatment that was done to the samples helped the metallographic structure. In terms of physics, it didn't change the hardness much, but it did make the material wear less quickly. [Display omitted] [ABSTRACT FROM AUTHOR]

Geopolymers represent a distinct class of materials characterised by their X-ray amorphous nature and nanoporous, nanoparticulate structure. Geopolymers can be conveniently mixed, poured, and cured under ambient conditions. This makes this class of materials an interesting alternative to ordinary Portland cement for structural processes. Additionally, the addition of alumina can improve mechanical properties, while the addition of glass can form an impermeable glaze which could be useful for molten salt containment. Therefore, in this investigation, potassium metakaolin-based geopolymer composites with varying proportions of glass particles and alumina platelets were fabricated, cured, heat-treated, and analyzed to study the effects of composition on material properties. Various attributes including rheological properties, densities, mass loss, shrinkage, and porosities were compared. It was observed that certain compositions exhibited high viscosities, making high shear mixing challenging, while also displaying significant permeability that would hinder their ability to contain liquids without leakage. Additionally, certain samples showed reduced densities, suggesting potentially weaker mechanical properties; however, the investigation did not include a direct assessment of mechanical properties. The most promising candidates for containing liquids at high temperature contained 50 wt% KGP, 25 or 35 wt% glass powder, and 25 or 15 wt% alumina platelets, respectively. ASH-G slurries required a minimum of 65 vol% KGP to produce a homogenous material compatible with additive manufacturing. The minimum amount of glass phase to form surface glazes was 16 vol%. Only samples containing more glass phase than alumina phase produced glazed composites. [ABSTRACT FROM AUTHOR]

The study successfully enabled the creation of ceramic surfaces with multi functionalities, including superhydrophilicity, self-cleaning, antibacterial properties, and photocatalytic activity, by applying a glaze composition rich in nano ZnO/Cu–ZnO and utilizing surface chemistry and unique texturing on porcelain tiles. The tiles, coated with unique glaze compositions, were fired in an industrial furnace and heat treated. The crystalline phases and surface morphology of glazed surfaces were systematically evaluated using XRD, SEM, FT-IR, drop shape analyzer, and surface roughness profilometer. Key-factors affecting the wettability, self-clean ability, photocatalytic activity and antibacterial efficacy were discussed. Adding nano Cu into the glaze mixture that is rich in ZnO improves the evolution of zincite crystals, increases the specific surface energy, decreases surface roughness, provide superhydrophilicity and promotes the antibacterial effectiveness and photocatalytic activity. Superhydrophilic surfaces doped with nano Cu–ZnO display antibacterial characteristics that do not require UV or visible light. The quick achievement of complete self-cleaning, up to 100 %, is due to the presence of nano Cu particles in its structure. Hydrophilicity has the ability to improve the efficiency of photocatalysis. If a surface exhibits superhydrophilic properties, it shows exceptional photocatalytic performance. A surface that is solely photohydrophilic may not maintain self-cleaning. Hydrophilicity may be more important than photocatalysis in the self-cleaning effect. [ABSTRACT FROM AUTHOR]

Photo-stimulated luminescent materials are one of the most attractive alternatives for next-generation optical information storage technologies. However, there are still some challenges in regulating appropriate energy levels of traps in luminescent materials for optical information storage. Herein, a green emission nanophosphor Zn 2 SiO 4 : Mn2+, Cr3+ with the trap depth of 1.05 eV, fulfilling the requirements for optical information storage, was fabricated for the first time through the solution combustion method and subsequent heat treatment at 1000 °C for 2 h. The crystal structure, micromorphology, photoluminescence (PL), photoluminescence excitation (PLE), and afterglow properties of Zn 2 SiO 4 : Mn2+, Cr3+ were studied systematically. By applying the strategy of trap depth engineering, high trap density with proper trap depth was observed when Cr3+ ions were introduced into Zn 2 SiO 4 : Mn2+. Thermoluminescence (TL) glow-curve analysis through the initial rise (IR) method was conducted to gain some insights into the information of traps. As proof of application, optical information storage was experimentally achieved by choosing 275 nm illumination for "information writing" and 980 nm NIR excitation for "information reading". The results indicate that Zn 2 SiO 4 : Mn2+, Cr3+ phosphor holds promise for potential applications in the field of optical information storage. [ABSTRACT FROM AUTHOR]

Biomedical coatings were elaborated by pulsed electrodeposition with hydrogen peroxide (H 2 O 2) into electrolytes on Ti 6 Al 4 V substrates, and the effect of H 2 O 2 concentration on the electrolyte and the heat treatment was studied. The experimental procedures employed in this study produce a consistent hydroxyapatite coating. This coating is well-suited for use in bio-implants, as it enhances the integration of the implant with surrounding bone tissue and improves the mechanical performance. The coatings' surface morphology and chemical composition were assessed using scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDXS) for x-ray microanalysis. X-ray diffraction (XRD) was also utilized to identify the phases and composition of the coatings. Nanoindentation and scratch tests were conducted to analyze the nanomechanical properties and adhesion behavior. Potentiodynamic polarization was employed in the Ringer solution to evaluate the corrosion resistance and replicate the conditions of the human body environment. The results of our thorough investigation revealed that employing pulsed electrodeposition with 9 % H 2 O 2 in the electrolyte, combined with subsequent heat treatment, facilitated the creation of coatings comprising two distinct phases: stoichiometric hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP). Our meticulous research underscores the significance of this process in achieving these specific coating compositions. Under these tests listed above, this composite demonstrated favorable mechanical properties (E = 30.45 GPa and H = 72.2 MPa). It also exhibited superior scratch adhesion and a critical load of 23 MPa and 12 N, respectively. Additionally, an improvement in tribological comportment was observed, and the wear volume decreased from 4.15 106 μm3 to 2.44 106 μm3. The HAP coating heat treated with 9 % H 2 O 2 exhibited the highest corrosion resistance, with E corr at −0.189 V/SCE and i corr at −1.11 μA cm−2 [ABSTRACT FROM AUTHOR]

The volume expansion and poor conductivity greatly limit the application of silicon as an anode for lithium-ion batteries. Although nanocrystallization of silicon and its surface carbon coating can be improved to some extent, the serious problems of particle aggregation and structural instability have not been effectively solved. In this paper, gelatin and sodium alginate (GE + SA) derived carbon/silicon composites are successfully prepared by a liquid-phase method, the freeze-drying technique, and heat treatment. Si nanoparticles (NPs) are uniformly encapsulated in a three-dimensional network of N-doped carbon that is enriched with a rich pore structure. The reversible capacity of the particular Si@C composite electrode was maintained at 580 mA h g−1 after 300 cycles at a current density of 1 A g−1, showing good cycling stability. Meanwhile, the anode also has excellent rate performance with reversible capacities of 2230, 1458, 1101, and 686.6 mA h g−1 at current densities of 0.1, 0.5, 1, and 2 A g−1, respectively. The GE + SA derived carbon/silicon composites effectively solve the problems of particle aggregation and an unstable carbon/silicon interface structure and can become candidates for anode materials in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Constructing multifunctional films using layered rare earth (RE) hydroxide (LRH) nanosheets as building blocks is a popular topic. The traditional synthesis of LRH films involves four main steps: bulk crystal synthesis, intercalation of long-chain organic anions, exfoliation, and layer-by-layer self-assembly into a film. In this work, the layered gadolinium hydroxide (LGdH) film was directly synthesized via electrodeposition within 10 minutes. The effects of the synthesis conditions, including working voltage, concentration of nitrate solution, and the reaction temperature, on the structural characteristics and morphologies were investigated. In order to improve the photoluminescence performance of LGdH:RE films, the quenching groups in the LGdH structure were removed/replaced via appropriate heat treatment/anion exchange with MoO42−, based on the thermal behaviour/anion exchange properties of the LGdH, and Gd2O3:RE/NaGd(MoO4)2:RE films with enhanced photoluminescence and stability were obtained. The electrodeposition combined with heat treatment/anion exchange techniques established in this study led to the rapid synthesis of Gd2O3:RE/NaGd(MoO4)2:RE films, and could have wide implications for the generation of other types of inorganic functional films. [ABSTRACT FROM AUTHOR]

MgO-Al 2 O 3 -SiO 2 -ZnO-TiO 2 -ZrO 2 glass with the addition of 8 mol% Na 2 O as flux has been prepared by the melt-casting method, and transparent glass-ceramics (GCs) with spinel (MgAl 2 O 4 and ZnAl 2 O 4) as the main crystalline phases were prepared by controlled crystallization. The optimum nucleation temperature was determined through DSC method, which is conducted on the glass with different preheating temperatures. The type and size of crystals in MAS glass-ceramics are highly dependent on the heat treatment. As the nucleation time increased to over 25 h, the formation of spinel was hindered due to the increasing formation of Na 2 TiSiO 5 in the glass, which consumed most of the Ti4+ ions during the long-term nucleation. When the nucleation time is up to 35 h, there is only Na 2 TiSiO 5 crystalline phase in the GCs. The nucleation time have a significant effect on the ion-exchange process through changing the crystals type and microstructure of GC. Both the Na + ions in Na 2 TiSiO 5 crystals and glassy phase can participate ion-exchange with K+ ions in molten salts, facilitating to form compressive stress. While, the formation of spinel consumed a lot of [AlO 4 ] in glassy phase, which decreasing the ion-exchange channel and thus hindering the ion-exchange. When heat treated at 700 °C/25 h + 830 °C/1 h, the MAS glass-ceramic showed transparency over 78 % at 550 nm, and its Vickers hardness reached ∼845 kgf/mm2 after ion-exchange. [ABSTRACT FROM AUTHOR]

In this paper, a Fe 2 O 3 /g-C 3 N 4 nanocomposite was prepared using a facile precipitation method, demonstrating the influence of g-C 3 N 4 nanosheets on the photocatalytic efficiency of α-Fe 2 O 3. Despite the stability of pure g-C 3 N 4 during heat treatment up to 700 °C, its presence, along with iron oxide during calcination, reduces its stability temperature to about 450 °C. The reduction of hematite to magnetite by carbon is accompanied by the decomposition of g-C 3 N 4. The appropriate calcination temperature determined for this synthesis process is 390 °C. Microscopic analysis revealed a uniform distribution of α-Fe 2 O 3 particles (average particle size of 16 nm) on g-C 3 N 4 nanosheets with a close and intimate contact. The g-C 3 N 4 content in the nanocomposite influenced the size of Fe 2 O 3 nanoparticles. g-C 3 N 4 nanosheets in the α-Fe 2 O 3 structure changed the band gap from 1.9 to 2.4 eV, reducing the recombination rate of electrons and holes. A nanocomposite containing 10 wt% g-C 3 N 4 showed the highest photocatalytic performance. The Z-scheme charge transfer mechanism and the significant role of superoxide radicals in the photocatalytic process were identified. The nanocomposite's photocatalytic efficiency was evaluated on various pollutants, including methylene blue (MB, 88 %), phenol (60 %), methyl orange (MO, 38 %), and the pharmaceutical compound Metformin (96 %). The α-Fe 2 O 3 /10 wt% g-C 3 N 4 nanocomposite exhibited the highest hydrogen production rate at 435 μmol/g.h, establishing its importance in photocatalytic performance. [ABSTRACT FROM AUTHOR]

The sagger, primarily composed of aluminum-silicon, serves as an essential vessel in the sintering process of ternary lithium battery anode materials (LiNi x Co y Mn 1-x-y O 2 , LNCM). However, the acidic oxide SiO 2 in the sagger material readily reacts with Li 2 O in the cathode material, forming substances such as LiAlO 2 or LiAlSiO 4 , resulting in volume expansion, which makes the sagger spalled and damaged. In this study, β-Al 2 O 3 –MgAl 2 O 4 multiphase materials with excellent alkali resistance were prepared using the high-temperature solid-state method. The effects of anhydrous sodium carbonate content and heat treatment temperature on the properties of the composites were investigated, and the thermal shock resistance of the specimens was evaluated by the water-rapid-cooling method, as well as the LNCM corrosion resistance of the specimens was evaluated by the static crucible method. The results showed that the overall performance of the specimens was the best at a anhydrous sodium carbonate content of 6 wt%, with a compressive strength of 57.50 MPa and a flexural strength of 42.49 MPa after firing at 1600 °C for 4 h. The strength retention of the specimens was 33.21 % after one thermal shock at a thermal shock temperature of 900 °C. The specimens showed excellent resistance to erosion as there were no obvious erosion traces on the surface of the specimens after undergoing five cycles of erosion. [ABSTRACT FROM AUTHOR]

In recent years, SiC aerogels have attracted considerable research interest owing to their excellent high-temperature resistance. It is crucial to research and improve the thermal stability of SiC aerogels under long and multiple heat treatments. Herein, we develop a series of monolithic SiC aerogels with a density of 0.23–0.28 g cm−3, low-thermal linear shrinkage of 21%–27 %, and high compressive strength of 0.38–0.60 MPa by designing a novel core–net structure. The resulting aerogels exhibit excellent thermal insulation thermostability and high-temperature reusability. Thermal conductivities of 0.0455–0.0678 W K−1 m−1 and 0.0934–0.1313 W K−1 m−1 were achieved at 40 °C and 900 °C, respectively. Following three consecutive heat treatments using a butane spray gun for 2000 s, the macromorphology exhibited no change, and the backside temperature was 230 °C. The results demonstrate an effective solution to reuse aerogels as long-lasting high-temperature insulation materials. [ABSTRACT FROM AUTHOR]

Alumina-spinel and alumina-magnesia castables are important for steel ladle applications primarily for the bottom and side wall areas respectively. Presence of spinel in alumina castables enhances the resistances against corrosion and thermal shock and improves the performance and service life of the steel ladles. Development of these type of castables is planned in the present study in presence of Cr 2 O 3 as an additive using high alumina cement as binder. Variation in spinel (10 and 20 wt%) and MgO (2.8 and 5.6 wt%) content was also explored, along with two different particle size distributions (q value 0.21 and 0.29) for different flow consistencies. The castable compositions were processed conventionally and evaluated for various refractory properties after heat treatments at 110, 1000 and 1550 °C. Both the castables showed well developed refractory properties with alumina-magnesia castable having better slag resistance due to greater extent of calcium hexa aluminate phase formation protecting the refractory. [ABSTRACT FROM AUTHOR]

Background: The size effect and deformation instability exhibited by materials at the micro- and nano-scale constrain the development and application of miniaturized devices. Introducing different defects in materials through different technical means to improve the deformation stability of materials has been the main research point of micro- and nano mechanics. Objective: This paper presents a novel strategy to completely eliminate the instability of microscopic deformations by the introduction of high-density precipitates in aluminum alloys by means of suitable heat treatment. Methods: A suitable heat treatment is used to introduce a high density of precipitates in the 7075 aluminum alloy. Using the Focused Ion Beam technique and in situ micropillar compression tests, micron-sized single-crystal micropillars were fabricated and the size dependence of the strength and strain-hardening behavior of 7075 aluminum alloy was systematically analyzed. Results: Compared with precipitate-free Al–Mg alloy micropillars, the micropillars fabricated from 7075 aluminum alloy exhibited more stable deformation behavior, predominantly due to the impediment of dislocation motion by precipitates. The power-law exponent for yield strength relative to pillar size was determined to approach a near-zero value, indicating a negligible dependency of yield strength on specimen size. Similarly, the smaller the size of micropillar, the higher the hardening rate, which can be rationalized by exhaustion hardening. Conclusions: The proposed method can eliminate the size effect of materials with pillar size above 0.5 μm and leads to a stabilization in deformation behavior. These are advantageous for the application of micro- and nano-sized components in advanced engineering systems. [ABSTRACT FROM AUTHOR]

Summary: This study examined the rheological and textural properties of gels produced through emulsion gelation using pea protein isolate (PPI). Emulsions were prepared with varying PPI concentrations (2%–10%) and 0.25 oil fraction, followed by heat treatment. Higher PPI concentrations improved encapsulation efficiency (EE), but heat slightly reduced it, though EE remained above 90%. Droplet size decreased with higher PPI. The emulsion was then gelled with different kappa‐carrageenan (KC) concentrations (1%–2%) and pH levels (4–7). Gel hardness increased with KC content, while adhesiveness decreased. Springiness, cohesiveness and water‐holding capacity (WHC) rose with pH and KC, while meltability decreased. Rheological tests showed stronger gels with higher KC and lower pH. Storage time generally increased gel strength, except at pH 4. This work highlights the interplay between PPI, KC, pH and storage time in shaping the properties of pea protein‐based emulsions and gels. [ABSTRACT FROM AUTHOR]

Summary: Texture is a multi‐parameter attribute and one of the prime quality attributes of fried products. This study examined the influence of post‐frying holdings under a heat lamp on the texture of breaded fried chicken nuggets. Chicken nuggets were deep‐fat fried (2, 4, 6, and 8 min) in canola oil at 180 °C. The fried samples were kept under an infrared heat lamp for up to 1 h, and the textural characteristics were compared with samples not exposed to post‐frying holdings. Textural characteristics were analysed through mechanical‐acoustic approach. The mechanical‐acoustic parameters related to crispiness analysed included maximum force (Fmax, N), number of force peaks (NFP), the area under force‐deformation curves (AF, N.sec), sound pressure level (SPL, dB), number of sound peaks (AUX) and the area under the amplitude‐time plots (AS, dB.sec). The mechanical parameters (Fmax: 19.11–48.96 N; NFP: 5–40; AF: 43–135 N.sec) of chicken nuggets increased with frying time, and these attributes were decreased during post‐frying holding. Similarly, acoustic parameters (SPL: 64.75–90.67 dB; AUX: 180–795; AS: 63–98 dB.sec) of chicken nuggets increased with frying time, and these attributes were decreased during post‐frying holding. Considering the studied parameters, 6 min of frying was found as optimal frying time. However, the post‐frying infrared heat lamp treatment affected the mechanical textural parametres more than the acoustic parameters. Findings from this study will be useful to food industries in optimising textural retention during post‐frying heat lamp holdings of fried products. [ABSTRACT FROM AUTHOR]

Summary: The growing global population has increased the protein needs and the combination of animal with plant proteins can be an effective strategy to meet future protein demand. This study aimed to investigate the impact of pH between 6.2 and 7.0 on the thermal stability of a 1:1 mixture of chickpea protein concentrate (CPC) and whey protein isolate (WPI), and their respective control. After heat treatment, CPC:WPI mixture showed an increase in viscosity (from 20.5 mPa.s at pH 7.0 to 110.8 mPa.s at pH 6.2, respectively), and particle size (from 5.7 to 56.5 μm at pH 7.0 and 6.2, respectively). The physical stability of the heat‐treated CPC:WPI mixture decreased, as the sediment increased from 3.3 mm at pH 7.0 to 7.8 mm at pH 6.2. This study highlighted the enhanced thermal stability of CPC:WPI at pHs closer to neutrality and offers valuable insights for the formulation of innovative plant protein‐enriched food. [ABSTRACT FROM AUTHOR]

Additive friction stir deposition (AFSD) is a relatively new metal additive manufacturing technique with many advantages compared to fusion-based methods. Despite the recent developments, the research about AFSD is in the initial stages, and processing hard and strong materials such as Aluminum 7075 is still challenging. In this study, a set of processing parameters is introduced and optimized for the AFSD of defect-free Al 7075 parts. Microstructure, electroconductivity, and mechanical properties of the as-deposited parts are studied. Compared with feedstock, the results indicated that the conductivity of the printed specimens increased by 19.5%, and the strength and hardness experienced a significant decrease by 54.4% and 43.5%, respectively. The change in the properties was associated with the precipitation enlargement and aggregation during the AFSD process. Subsequently, heat treatment was conducted to recover the mechanical properties, and noteworthy enhancements, a 101.2% increase in hardness and a 49.1% increase in strength, were recorded compared to the as-deposited condition due to the smaller and more uniformly distributed secondary phases in the matrix. [ABSTRACT FROM AUTHOR]

Tool-grade steels designed for the manufacture of hot-forming dies have been studied. An economically alloyed modified steel 70Kh3G2FTR(m) is proposed, which has a fine metal base structure with uniform carbide hardening in the heat-treated state. The comparative structural studies with traditional tool-grade steels (5KhGM, 4Kh5MFS) at different stages of heat treatment, as well as the statistical analysis of mechanical properties (hardness and toughness) from thermal hardening parameters, allowed us to develop an optimal heat treatment technology, which provided the required indicators for the structure, hardness, and heat resistance of the material. It is shown that 70Kh3G2FTR(m) steel retains its strength and the effect of microalloying at elevated operating temperatures, which is confirmed by data from transmission electron microscopy, dynamic mechanical analysis, and thermophysical properties in the field of operating temperatures up to 400 °C, as well as studies of the samples' texture under thermal exposure. The assessment of the mechanical properties, wear resistance, and economic effect of the introduction of the developed material and its thermal hardening technology make it possible to reasonably recommend 70Kh3G2FTR(m) steel as a rational replacement for traditional materials. [ABSTRACT FROM AUTHOR]

Binary CaO‐MgO‐Al2O3‐SiO2 (CMAS) ceramics composites of anorthite‐cordierite composition were synthesized from natural raw materials (kaolin and dolomite rock). The change of SiO2/Al2O3 ratio in kaolin/dolomite mixtures (12, 24, and 36 wt.%) and synthesized composites along with analysis of their phase composition transformations (X‐ray diffraction) during heat treatment (thermogravimetric and differential thermal analysis) give the controlled design of aluminosilicate matrices. The obtained ceramic composites are represented by anorthite, a cordierite‐like phase whose ratio varies from 1.3:1 to 2.8:1. Mullite crystals, also included in the composition, reinforce the anorthite‐cordierite matrix. The morphostructural features of the samples were studied using optical and scanning electron microscopy. The porosity ranges from 7.8% to 24.2% depending on dolomite content. The impurities of iron and titanium interfering with obtaining a qualitative product are leveled by the presented technique including the heat treatment scheme justified by thermogravimetric analysis. Obtained CMAS‐ceramics of anorthite‐cordierite composition correspond to industrial international standards by their technical characteristics and exceed the requirements for heat‐insulating and chemically resistant materials by compressive strength. [ABSTRACT FROM AUTHOR]

In this work, Cr3+ ion introduced germanate transparent glass-ceramics with one-step heat treatment around the glass transition temperature were prepared. By using TEM and other structural characterizations, it was demonstrated that the microstructure of glass-ceramics had uniform distribution and excellent grain development. Through XPS, FTIR, Raman and JMA model calculation, it was found that the substitution of Cr 2 O 3 for Ga 2 O 3 led to the decrease of [TO 4 ] ratio in the glass network, and the crystallization behavior changed to the whole crystallization. The results of optical performance tests indicated that the transmittance of the transparent glass-ceramics with one-step heat treatment was 46 % higher than that of glass-ceramics prepared by the two-step heat treatment, and the broadband emission intensity at 980 nm was 1.69 times higher than that of the basic glass. There is some guiding relevance to the innovative preparation approach suggested in this work for the creation of transparent glass-ceramics. [ABSTRACT FROM AUTHOR]

The present study focuses on the effect of molybdenum and nitrogen on the microstructure and mechanical properties of VC x O y -Fe cermets. Samples with 0–23 at% Mo were fabricated using a wet synthesis route and heat treatment under Ar and N 2 atmospheres. Phase transformations during heating were investigated by TGA-DSC in combination with XRD, and the resulting materials were analyzed by SEM/EDX. A doping level of 6–12 at% was found to be optimal, as it lowered the melting point of the metallic binder to 1320–1360 °C. Replacing argon with nitrogen further decreased the melting point to 1210–1240 °C and reduced the grain size. Depending on the sintering temperature, gas environment, and molybdenum content, the produced cermets were characterized by 92–97 % density, 17–29 vol% binder phase, 8–14 GPa hardness, and 6–9 MPa m0.5 fracture toughness. The average size of oxycarbide grains, their stoichiometry, and the amount of dissolved vanadium in the iron binder demonstrated a strong correlation with changes in mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymer-derived ceramics (PDCs) exhibit diverse microstructures and varying levels of free carbon after pyrolysis at different temperatures, resulting in distinct wave-absorbing capabilities. In this study, PCS, PSN1, and PSN2 with different free carbon concentrations were subjected to heat treatment, followed by systematic characterization of their microstructures, particularly the transformation process of free carbon. Subsequently, the dielectric constants and microwave-absorbing properties of the heat-treated PDC powders within the 2–18 GHz range were determined using the coaxial method. Finally, an analysis was conducted on the relationship between loss mechanisms and microstructure in PDCs to establish a foundation for preparing broadband wave-absorbing ceramic matrix composites. [ABSTRACT FROM AUTHOR]

This study offers a detailed examination of vinyl ester composites strengthened with nettle fibres and annealed biosilica from foxtail millet husk biomass waste. The primary objective is to investigate how the different dwell time processed heat treated biosilica particles perform under repeated and prolonged loading applications in natural fibre-reinforced polymer composite materials. The biosilica particles were annealed at 1200 °C and dwelled for 2 h and 4 h. The results highlight VNS32 (resin with nettle fibre of 30 vol.% and biosilica of 2 vol.%) as the superior composite, exhibiting higher fatigue counts of 29,108, 27,898, and 26,247 for 25%, 50%, and 75% of the ultimate tensile strength (UTS). Similarly, VNS32 demonstrates superior values in creep and dynamic mechanical analysis (DMA). In creep testing, VNS32 shows creep strain values of 0.0015, 0.0019, and 0.0035 for 5000 s, 10,000 s, and 15,000 s, while in DMA, it achieves a storage modulus of 5.6 GPa at 107 °C and a loss factor of 0.42. These findings suggest that the utilization of prolonged annealed biosilica contributes to enhanced structural integrity and uniform load transfer, both in normal and cyclic loading conditions at specific temperatures. Moreover, these composites could be used in automotives, lightweight building material applications, drones, defence and food packaging where lightweight and high strength is required. [ABSTRACT FROM AUTHOR]

A lead-free Ni–B–W (ENB-W) coating deposited by electroless method was investigated in present work. Heat-treated ENB-W coating (450 °C for 3 h) were exposed to tribological tests within a range of parameters, including load (10–50 N), speed (0.5–1.5 m/s), and distance (400–1000 m). Prior to tests, coated specimens before and after heat-treated condition were characterized. The typical globular morphology and crystalline nature was seen. The hardness, scratch hardness and first critical load of failure improved in heat treated condition. To optimize wear rate and coefficient of friction (COF), an approach has been introduced, i.e., integration of an artificial neural network (ANN) with a genetic algorithm (GA). The ANN model yielded a mean absolute percentage error of 8.4421% for predicting wear rate and 2.4138% for predicting COF. Pareto front analysis identified the optimal operating conditions as load of 34.2099 N, speed of 0.5006 m/s, and distance of 726.7243 m, resulting in both a minimum wear rate of 0.1003 × 10−8 g N−1 m−1 and a COF of 0.2099. In addition to optimization, the study also involved the characterization of the wear mechanisms of the coatings to gain a deeper understanding of their tribological behaviour. Different wear mechanisms were seen at different range of the parameters. The wear rate and COF did not vary significantly with sliding distance except at 10 N load. In fact, the wear rate was lower at 30 N and 50 N compared to 10 N. [ABSTRACT FROM AUTHOR]

In this study, the microstructure, hardness, tensile strength, and dry wear properties of the cast AlSi10Mg alloy as well as the effects of processing parameters on the oxidation behavior of this alloy were investigated. In this context, AlSi10Mg (wt%) alloy was produced by gravity die casting method, and then, air cooling, quenching, and T6 treatment were applied. The microstructure of the alloy was investigated using an optical microscope, SEM, and EDS. Additionally, thermogravimetric analysis (TGA) was used to determine the effect of processing parameters on the oxidation behavior of the samples. The friction and wear properties of the alloy were investigated using a ball-on-disk wear test device. It was founded that the as-cast AlSi10Mg alloy's microstructure contained phases of α(Al), Si, and β-Mg2Si. It has been observed that the microstructure of the cast AlSi10Mg alloy gradually turns into a spherical form when quenching and air-cooling heat treatments are applied. Also, T6 heat treatment led to further spheroidization of Si particles, formation of β-Mg2Si precipitates, and elimination of the Chinese script morphology of the β-Mg2Si phase. It was observed that the yield strength of the AlSi10Mg alloy in the as-cast state decreased negligibly compared to the air-cooled state, while there was an increase of up to 70% in the aging-treated condition. The results show that the tensile strength of the as-cast AlSi10Mg alloy increased by 115% after aging. Additionally, it was found that the AlSi10Mg alloy's wear resistance increased with the aging process. [ABSTRACT FROM AUTHOR]

This study explores a novel approach to quenching and partitioning (Q&P) heat treatment applied to AISI 9260 spring steel, comprising Fe-0.65C-1.58Mn-1.05Si-0.41Cr (wt.%). Our research focuses on balancing strength and ductility through optimized Q&P pathways, leading to a diverse microstructure that includes martensite, bainite, carbide, and retained austenite. Advanced X-ray diffraction and scanning electron microscopy techniques were employed to analyze the complexities of this microstructure. A key aspect of this study is the precise control of partitioning temperature and time, crucial for modulating lattice distortion and dislocation density within martensitic and bainitic structures. Optimal partitioning temperature promotes carbon distribution into austenite, tempering lattice distortions, and dislocation densities. Concurrently, carbide precipitation and segregation contribute to the refinement of the bainite phase. The sample quenched at 125 °C and partitioned at 350 °C (Q&P-125/350) demonstrates notable mechanical properties: a yield strength of 950 ± 15 MPa, an ultimate tensile strength of 1710 ± 15 MPa, and an elongation of approximately 9.7%. These results are partly attributed to the effect of silicon in preventing cementite coarsening and the effective distribution of carbide. Our findings highlight the potential of Q&P heat treatment in developing tailored microstructures with enhanced mechanical properties in steel, without relying on costly alloying elements. This approach presents new avenues for the design and application of high-performance materials. [ABSTRACT FROM AUTHOR]

In the study, the effects of hybrid reinforcement (nano-alumina and MWCNT) and heat treatment on the wear behavior of the Al–4Cu nanocomposites were investigated under dry sliding condition against W–6Co ball by means of a ball-on-disk type tribometer. The load and the sliding speed were kept constant and selected to be 10 N and 0.1 m s−1, respectively, in the course of the wear tests. Meanwhile, the wear tests were completed after a total sliding distance of 1500 m was reached for each case. During these tests, the wear loss of the nanocomposites was measured at every 250 m. The worn surfaces of the nanocomposites were examined with the help of stereo and scanning electron microscopes. The volumetric wear rates, wear coefficients and wear mechanisms were identified for the nanocomposites to clarify the influence of reinforcement content and heat treatment on their wear resistance. The volume loss at the wear distance of 1500 m was obtained as 24.9 and 8.2 mm3 for the annealed and aged Al–4Cu alloy, respectively. On the other hand, it decreased to 4.6 and 3.2 mm3 in the case of the nanocomposites with 15% hybrid reinforcement in the annealed and aged conditions, successively. Moreover, increasing the hybrid reinforcement amount decreased the wear loss of the aged nanocomposites substantially in such a way that it resulted in the mild wear. [ABSTRACT FROM AUTHOR]

Commercially available powders of detonation nanodiamond (DND) contain extrastrong 20–120 nm sized aggregates, in an amount sometimes up to 50% by mass sustainable to the conventional methods of deaggregation. It demonstrates the significant inhomogeneity structure of products of detonation synthesis and noticeably reduces the yield of 4.0 − 5.0 nm individual isolated particles obtained from DNDs. The presence of these aggregates is obviously related to the some essential features of detonation synthesis. This work presents the results of studying such extrastrong aggregates from DND powder. In order to determine the structure we applied the heat treatment of samples in vacuum and in air, and the subsequent study using Raman spectroscopy, X-ray diffraction, UV–vis spectroscopy, analysis of specific surface and dynamic light scattering (DLS). As a result, a structural model of extrastrong aggregates is proposed. It is shown that extrastrong aggregates consist notably of relatively large (∼8.0 nm) single crystalline diamond particles bonded by facets and covered by smaller 4.5 − 3.0 nm and less crystalline grains. Our results add the details for description of formation processes of diamond particles and aggregates in detonation synthesis from excessive carbon in the composition of explosives. [ABSTRACT FROM AUTHOR]

Freeze casting is an effective way to fabricate the porous ceramics with anisotropic and interconnected porous structures and can be used in various applications, such as filtration, adsorption, and insulation. However, the ceramic‐based scaffolds fabricated by freeze casting have the upper limit of porosity since excessively low solid content in the slurry will lead to structural instability and cracks formation in scaffolds. This study aims at combining the freeze casting and sol–gel method and developing a hybrid process to overcome the limitation of freeze casting. Besides, the effects of solid content and cooling rates on the microstructure of ultralightweight alumina scaffolds (ULASs) and their mechanical and thermal properties were investigated. Aluminum isopropoxide was selected as the precursor to conduct the hydrolysis reaction in acid environment and condensation process by heat treatment. The successfully synthesized alumina scaffolds have ultrahigh porosity (>90%), low bulk density (0.1240–0.2429 g/cm3), and low relative density (0.0314–0.0615). The anisotropic porous lamellar structure was evaluated by scanning electron microscope, µ‐CT, and mercury porosimeter. A lot of nanoscale pores are observed on the lamellae surfaces, forming the dual‐scale porous structure inside the scaffolds and contributing to higher specific surface area. The unique anisotropic structure, high porosity, and stable mechanical properties enable ULASs to deliver a low thermal conductivity of 0.2 W/m/K and large anisotropy in thermal properties, possessing great potential for thermal insulative materials. This sol–gel/freeze‐casting hybrid approach is believed to be extended to different material systems and provide promising potentials in fabricating the porous materials with various functionalities. [ABSTRACT FROM AUTHOR]

Copper nanoparticles (CuNPs) were successfully prepared in Cu+–Na+ ion‐exchanged commercially available silicate glasses followed by being annealed in Ar/H2 atmosphere; in an approach that can be quite economic capable of modifying the physicochemical properties of glass. This approach resulted in the growth of spherical and crystalline CuNPs, with an average size of 67.5 nm, which is greater than the CuNPs average size obtained with annealing at air atmosphere (15.8 nm). On the treated glasses, phase transitions indicative of a shape memory effect and dendritic structures were also detected, indicating their vital roles, as crystal growth mechanisms in the resultant CuNPs. The surface plasmon peaks of CuNPs have been clearly observed in absorption spectra of doped annealed glasses at 350, 450, and 550°C in Ar/H2. Photoluminescence studies have proved the presence of both Cu+ and Cu2O. The detailed methodology and the structural and morphological characterizations of the annealed copper ion‐exchanged samples were carried out using optical microscopy (OM), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy and high‐resolution TEM (TEM and HRTEM), and their reasoning are thoroughly described and discussed. [ABSTRACT FROM AUTHOR]

Double‐layer thermal barrier coatings are one of the development directions of thermal barrier coatings technology. LaYbZr2O7 (LYZO) has high toughness and low thermal conductivity, making it promising for use as a high‐temperature thermal barrier coating. However, its relatively poor mechanical properties, especially low fracture toughness, limit its further application. Therefore, we prepared a double‐layer coating of LYZO and Y2O3 partially stabilized ZrO2 (YSZ) using atmospheric plasma spraying, with the inner layer being YSZ and the outer layer being LYZO. The results showed that after spraying, LYZO was in the metastable fluorite phase, while YSZ was in the tetragonal phase. LYZO and YSZ had good chemical compatibility, and an interaction layer formed at the interface between them, with its thickness increasing with the sintering time. Eventually, after 100 h of heat treatment, the thickness reached 12 µm. The hardness of the LYZO/YSZ interface increased with the sintering time, reaching a maximum value after sintering at 1300°C for 10 h. When evaluating the interfacial bonding strength using indentation method, the length of cracks caused by indentation significantly decreased with the increase of sintering time. The increase in bonding strength can be attributed to the formation of a reaction layer and the reduction of thermal residual stresses. Raman spectroscopy was used to measure the thermal residual strain at the LYZO/YSZ interface. Unbalanced distribution of thermal residual stress and M phase was observed near the interface. As the sintering time increased, both thermal residual stress and M phase content decreased. In summary, the double‐layer thermal barrier coating of LYZO/YSZ has good potential for development. [ABSTRACT FROM AUTHOR]

This study investigates the influence of thermal history on grain boundary (GB) energy and the grain growth behavior of SrTiO3 at 1425°C. Two thermal profiles were explored: (1) a single‐step sintering at 1425°C for 1 h and (2) a two‐step profile with sintering completed at 1425°C for 1 h with an additional 10 h at 1350°C. Electron backscattered diffraction and atomic force microscopy were utilized to measure the grain size and GB energy distributions, respectively, for the samples before and after grain growth at 1425°C for 10 h. The two‐step profile exhibits fewer abnormal grains and a slower growth rate at 1425°C than the single‐step profile. Additionally, the two‐step sample comprises few high‐energy GBs and a narrow GB energy distribution, which suggests that it had a lower driving force for subsequent grain growth. The thermal profile was able to sufficiently change the growth rate such that the two‐step sample results in a finer grain size than observed for the single‐step sample after 10 h at 1425°C despite being exposed to elevated temperatures for almost twice as long. These results suggest that GB energy engineering through thermal profile modification can be used to control the grain growth rate and abnormal grain growth likelihood. [ABSTRACT FROM AUTHOR]