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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]

In this manuscript, perovskite oxide LaCoO3/LaMnO3/LaCoO3 (LLL) trilayers and the single-layer LaMnO3 (LMO) and LaCoO3 (LCO) films are epitaxially grown on (001)-oriented SrTiO3 substrates by polymer-assisted deposition combining with heat treating in Ar, air, and O2 atmospheres, respectively. The crystal structure and magnetic properties are investigated. It is found that the responses of LMO and LCO films to oxygen content are different, and the magnetic property of LMO is more sensitivity to oxygen content than that of LCO. The oxygen content can directly affect the structure and magnetic properties of LMO and LCO layers, which, in turn, modulate the interfacial magnetic properties of the LLL trilayers through interlayer coupling. By comparison with the magnetic properties of the single-layer films, an abnormal ferromagnetic (FM) transition is found in the LLL trilayers at around 216 K, besides two known FM transitions corresponding to those in the LCO and LMO layers, respectively. It is suggested that the abnormal FM transition is attributed to Mn4+–O–Co2+ FM super-exchange interaction, which is induced by the charge transfer from Mn3+ to Co3+ ions and the interlayer coupling between the LMO and LCO layers. The interlayer coupling of the trilayers, including the interfacial coupling and the diffusion-induced inlayer coupling, dominates the interface properties, which are tuned by oxygen content-dependent charge transfer. The cooperative function of the orbital/charge structure and the interlayer coupling dominates the magnetic properties of the LLL trilayer under the tensile strain. These findings provide new avenues to regulate the electronic and magnetic states of perovskite oxide multilayers and another way to the development of multifunctional electronic devices. [ABSTRACT FROM AUTHOR]

In this study, influence of SbCl3 treatment on CdTe films deposited by the close space sublimation method was investigated. SbCl3 treatment was compared with conventional CdCl2 treated and untreated samples. It was determined that CdTe grew as Cd-rich and there was a slight decrease in Cd-amount after SbCl3 and CdCl2 treatments. In addition, a significant amount of Sb was detected in the SbCl3 treated sample. The samples crystallized in the cubic structure of CdTe. However, graded structures such as phase-I and phase-II with different structural parameters were formed. In the SbCl3 sample, it was revealed that the presence of Sb- caused a slight increase in the lattice parameter, compared to the other samples. Morphological analyses of the samples showed facet and large-small grain structures. CdCl2 treatment caused a slight decrease in grain size, while SbCl3 treatment resulted in a coarser and rougher grain structure. CdCl2 treatment increased transmittance, whereas SbCl3 treatment caused a decrease in transmittance (hence, an increase in absorbance). It was observed that the bandgaps were ∼1.49 eV in all samples, and annealing, as well as CdCl2 and SbCl3 heat treatments did not cause a sharp change in the bandgaps. Photoluminescence spectra revealed the presence of band-edge and shallow-level defect transitions (except CdCl2 treated) in the samples. All results suggest that SbCl3 heat treatment has a significant effect on CdTe and may be an alternative to CdCl2. [ABSTRACT FROM AUTHOR]

With the development of modern industry, the discharge of dye wastewater is increasing year by year, and the damage caused by this wastewater to the ecosystem is often irreversible. Therefore, the research on the harmless treatment of dyes has attracted much attention in recent years. In this paper, commercial titanium dioxide (anatase nanometer titanium dioxide) was heat treated with anhydrous ethanol to synthesize titanium carbide (C/TiO2). Its maximum adsorption capacity for cationic dyes methylene blue (MB) and Rhodamine B is 27.3 and 124.6 mg g−1, respectively, which is much higher than that of pure TiO2. The adsorption kinetics and isotherm model of C/TiO2 were studied and characterized by Brunauer–Emmett–Teller, x-ray photoelectron spectroscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and other methods. The results show that the carbon layer on the surface of C/TiO2 promotes the increase in surface hydroxyl groups, which is the main reason for the increase in MB adsorption. Compared with other adsorbents, C/TiO2 showed excellent reusability. The experimental results of adsorbent regeneration showed that the adsorption rate R% of MB was almost unchanged after three cycles. During the recovery of C/TiO2, the dyes adsorbed on its surface are removed, which solves the problem that the adsorbent cannot degrade dyes simply by adsorption. Additionally, C/TiO2 has a stable adsorption effect, is insensitive to the pH value, has a simple preparation process, and has relatively low raw material prices, making it suitable for large-scale operation. Therefore, it has good commercial prospects in the organic dye industry wastewater treatment. [ABSTRACT FROM AUTHOR]

The operational stability is a current bottleneck facing the quantum dot light-emitting diodes (QLEDs). In particular, the device working around turn-on voltage suffers from unbalanced charge injection and heavy power loss. Here, we investigate the operational stability of red emissive CdSe QLEDs operated at different applied voltages. Compared to the rising luminance at higher voltages, the device luminance quickly decreases when loaded around the turn-on voltage, but recovers after unloading or slight heat treatment, which is termed fatigue effects of operational QLED. The electroluminescence and photoluminescence spectra before and after a period of operation at low voltages show that the abrupt decrease in device luminance derives from the reduction of quantum yield in quantum dots. Combined with transient photoluminescence and electroluminescence measurements, as well as equivalent circuit model analysis, the electron accumulation in quantum dots mainly accounts for the observed fatigue effects of a QLED during the operation around turn-on voltage. The underlying mechanisms at the low-voltage working regime will be very helpful for the industrialization of QLED. [ABSTRACT FROM AUTHOR]

Ion beam fabrication of metastable polymorphs of Ga2O3, assisted by the controllable accumulation of the disorder in the lattice, is an interesting alternative to conventional deposition techniques. However, the adjustability of the electrical properties in such films is unexplored. In this work, we investigated two strategies for tuning the electron concentration in the ion beam created metastable κ-polymorph: adding silicon donors by ion implantation and adding hydrogen via plasma treatments. Importantly, all heat treatments were limited to ≤600 °C, set by the thermal stability of the ion beam fabricated polymorph. Under these conditions, silicon doping did not change the high resistive state caused by the iron acceptors in the initial wafer and residual defects accumulated upon the implants. Conversely, treating samples in a hydrogen plasma converted the ion beam fabricated κ-polymorph to n-type, with a net donor density in the low 1012 cm−3 range and dominating deep traps near 0.6 eV below the conduction band. The mechanism explaining this n-type conductivity change may be due to hydrogen forming shallow donor complexes with gallium vacancies and/or possibly passivating a fraction of the iron acceptors responsible for the high resistivity in the initial wafers. [ABSTRACT FROM AUTHOR]

Sesame is an allergenic food with an increasing allergy prevalence among the European/USA population. Sesame allergy is generally life-persisting, being the cause of severe/systemic adverse immune responses in sesame-allergic individuals. Herein, clinical data about sesame allergy, including prevalence, diagnosis, relevance, and treatments are described, with focus on the molecular characterization of sesame allergens, their cross-reactivity and co-sensitization phenomena. The influence of food processing and digestibility on the stability/immunoreactivity of sesame allergens is critically discussed and the analytical approaches available for their detection in foodstuffs. Cross-reactivity between sesame and tree nuts or peanuts is frequent because of the high similarities among proteins of the same family. However, cross-reactivity phenomena are not always correlated with true clinical allergy in sensitized patients. Data suggest that sesame allergens are resistant to heat treatments and digestibility, with little effect on their immunoreactivity. Nevertheless, data are scarce, evidencing the need for more research to understand the effect of food processing on sesame allergenicity modulation. The demands for identifying trace amounts of sesame in foods have prompted the development of analytical methods, which have targeted both protein and DNA markers, providing reliable, specific, and sensitive tools, crucial for the effective management of sesame as an allergenic food. [ABSTRACT FROM AUTHOR]

The cubic Sm@CdS quantum dots (QDs) are grown in a glass matrix with good thermal stability for the first time. The band gap of CdS particles embedded in glass is observed to be in the range of 3.8 to 2.4 eV. The present system is compared with CdS/Sm nanocrystals (NCs) doped in a silica-based glass system. The CdS quantum dots, having a size in the range of 3–6 nm, are grown in the silica glass. Structural characterization has been carried out using X-ray diffraction (XRD), which shows the cubic structure of Sm@CdS quantum dots in glass, whereas the pristine CdS Q-dot glass shows hexagonal structure. The optical characterization of the glasses has been carried out using a UV-visible spectrophotometer. A spectroscopic study showed a shift in optical transmittance due to thermal treatment, i.e., due to the growth of CdS quantum dots in the glass matrix. The semiconductor crystals are uniform in size and distributed evenly in the glass matrix. The size quantization effect has been seen in both systems. There is a drastic change in the optical band gap with the size of the quantum dots. Under natural sunlight, the hydrogen production experiment was conducted, and an increase of 42.5% in the hydrogen evolution rate was observed from 1 wt% Sm3+ doped CdS (3769.2 μmol h−1 g−1) heat-treated at 525 °C when compared to the CdS Q-dot glass with a similar heat treatment temperature (2626 μmol h−1 g−1). Such cubic CdS QD–glass nanocomposites have great significance owing to their potential applications in solar cells, LEDs, and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

The distribution of reinforcements and interfacial bonding state with the metal matrix are crucial factors in achieving excellent comprehensive mechanical properties for aluminum (Al) matrix composites. Normally, after heat treatment, graphene nanosheets (GNSs)/Al composites experience a significant loss of strength. Here, better performance of GNS/Al was explored with a hybrid strategy by introducing 0.9 vol.% silicon carbide nanoparticles (SiCnp) into the composite. Pre-ball milling of Al powders and 0.9 vol.% SiCnp gained Al flakes that provided a large dispersion area for 3.0 vol.% GNS during the shift speed ball milling process, leading to uniformly dispersed GNS for both as-sintered and as-extruded (0.9 vol.% SiCnp + 3.0 vol.% GNS)/Al. High-temperature heat treatment at 600 °C for 60 min was performed on the as-extruded composite, giving rise to intragranular distribution of SiCnp due to recrystallization and grain growth of the Al matrix. Meanwhile, nanoscale Al4C3, which can act as an additional reinforcing nanoparticle, was generated because of an appropriate interfacial reaction between GNS and Al. The intragranular distribution of both nanoparticles improves the Al matrix continuity of composites and plays a key role in ensuring the plasticity of composites. As a result, the work hardening ability of the heat-treated hybrid (0.9 vol.% SiCnp + 3.0 vol.% GNS)/Al composite was well improved, and the tensile elongation increased by 42.7% with little loss of the strength. The present work provides a new strategy in achieving coordination on strength–plasticity of Al matrix composites. [ABSTRACT FROM AUTHOR]

The presented work is focused on the influence of imposed strain on the weldability of Dievar alloy. Two mechanisms affecting the microstructure and thus imparting changes in the mechanical properties were applied—heat treatment (hardening and tempering), and rotary swaging. The processed workpieces were further subjected to welding with various welding currents. In order to characterize the effects of welding on the microstructure, especially in the heat-affected zone, and determine material stability under elevated temperatures, samples for uniaxial hot compression testing at temperatures from 600 to 900 °C, optical and scanning electron microscopy, and microhardness testing were taken. The testing revealed that, although the rotary swaged and heat-treated samples featured comparable microhardness, the strength of the swaged material was approximately twice as high as that of the heat-treated one—specifically 1350 MPa. Furthermore, it was found that the rotary swaged sample exhibited favorable welding behavior when compared to the heat-treated one, when the higher welding current was applied. [ABSTRACT FROM AUTHOR]

This paper presents constitutive equations that describe the hot flow behaviour of Virgin (VG) X20 and rejuvenated heat-treated creep exhaust (CE) X20 steels. The study provides a foundation for determining the effect of rejuvenation heat treatment on CE steels by making comparisons to the VG steel. Hot compression tests were conducted in the temperature range of 900 °C to 1050 °C, at strain rates of 0.1–10 s−1 to a total strain of 0.6, and stress–strain curves were obtained. The flow stress curves of both steels exhibited dynamic recovery (DRV) characteristics as the main softening mechanism. Constitutive constants of steady-state stresses were determined. The stress exponents, n, were 6.62 (VG) and 5.58 (CE), and the apparent activation energy values were 380.36 kJmol−1(VG) and 435.70 kJmol−1 (CE). Analysis of the activation energies showed that VG steel had better workability properties than CE steel and was easier to deform at high temperatures. Constitutive equations for predicting the flow stress in the two steels were established. This were verified by statistical tools: Pearson's correlation coefficient (R) and Absolute Average Relative Error (AARE). The results showed R-values were, 0.98 (VG) and 0.99 (CE), and the AARE values for VG were 4.17% and 9.01% for CE. The statistical parameters indicated a good correlation between the experimental and predicted values. The constitutive equations therefore adequately described the flow stress behaviour of both steels and can therefore efficiently analyse industrial metal forming schedules. [ABSTRACT FROM AUTHOR]

Herein, Fe–Si–Al-based soft magnetic composites (SMCs) doped with carbonyl iron powders (CIPs) at different concentrations were successfully prepared. The reaction between CIPs and core–shell Fe–Si–Al/SiO 2 heterogeneous composite powders, induced by the high temperature and concentration gradient during heat treatment, was investigated. The effect of doping CIPs at different concentrations on the microstructure and magnetic properties of Fe–Si–Al-based SMCs was also studied. During heat treatment, the Fe–Si–Al/SiO 2 powders inside the SMCs exhibited a complex reaction with the doped CIP. The reaction involved multidirectional migration of Al and Si, evolution of an Al 2 O 3 + SiO 2 -composite insulating layer and formation of composite ferromagnetic phases. Furthermore, the density, saturation magnetisation, permeability and core loss of Fe–Si–Al-based SMCs were improved by doping the composites with moderate amounts of CIPs. The Fe–Si–Al-based SMCs doped with 8-wt% CIPs exhibited the best comprehensive magnetic properties (permeability = 43.5, saturation magnetisation = 160.1 emu/g and core loss = 481.7 kW/m3 at 10 mT and 100 kHz). Compared with undoped Fe–Si–Al-based SMCs, the permeability and saturation magnetisation increased by 40.3% and 24.0%, respectively, and the core loss decreased by 18.8%. Thus, the proposed method can effectively address the restrictive relation problem between permeability and energy loss in these composites. [Display omitted] [ABSTRACT FROM AUTHOR]

Aerogel composites reinforced by fibers have found extensive applications in the field of thermal insulation and energy conservation. However, the composites are hindered by their high infrared radiation transmittance and weak interface adhesion in practical applications. Herein, we designed and prepared a novel thin composite called 'fiber/whisker/aerogel paper' (SWAP) with a thickness of less than 1 mm. The SWAP integrated SiC nanowhiskers (SiC nw) as opacifiers and ultrafine SiO 2 fibers as reinforcement, fabricated through wet manufacturing and sol-gel process. The 'fiber/aerogel paper' (SAP) and SWAP exhibited low thermal conductivity at room temperature, measuring 0.025 W/(m·K) and 0.033 W/(m·K), respectively. Additionally, they exhibited low densities of 0.195 g/cm3 and 0.225 g/cm3, respectively. Notably, SWAP exhibited excellent high-temperature insulation performance, primarily due to its low infrared transmittance (50% at 3 μm). The incorporation of SiC nw and ultrafine SiO 2 fibers collectively enhanced the interfacial adhesion with the aerogel matrix even amidst rigorous testing (weight loss less than 3%). SWAP also demonstrated flexibility, high thermal stability, hydrophobicity, and flame resistance. Furthermore, a comprehensive investigation into the performance variations and influencing g factors of the material was conducted under different heat treatment conditions. This research provides guidance for the application of such materials under high temperatures. [ABSTRACT FROM AUTHOR]

In this study, oxyfluoride glasses with chemical composition of 45SiO 2 –15Al 2 O 3 –10BaO–30BaF 2 -xTbF 3 (x = 0.2, 0.4 and 0.6 (mole ratios)) were prepared through the conventional melt-quenching method. Raman and FTIR spectra as well as molar volume calculations proved the creation of more non-bridging oxygens (NBOs) in presence of more TbF 3 content. Accordingly, absorption edge in UV–Vis spectra showed a slight red-shift to longer wavelengths. The glass with 0.4 mol ratios of TbF 3 , exhibited the highest photoluminescence emission and its green-to-blue intensity ratio was 0.66. Therefore, this sample was chosen and heat treated at 630, 650 and 675 °C to prepare glass ceramic samples. For the sample heat treated at 650 °C, photoluminescence intensity increased and green-to-blue intensity ratio reached 0.69. Also, lifetimes of green and blue emissions increased from 3.35 ms to 3.67 ms and from 2.95 ms to 3.10 ms, respectively, when the base glass heat treated at 650 °C. Formation of BaF 2 nanocrystals in glass ceramics moved the UV–Vis absorption edge to longer wavelengths significantly. Increment of the weak and dangling bonds in crystallized samples reduced Fermi energy, indirect and direct optical band gap energies from 3.792 eV to 3.301 eV, from 3.522 eV to 3.093 eV and from 4.095 eV to 3.582 eV respectively, which led to higher semiconducting behaviors. [ABSTRACT FROM AUTHOR]

The glass of composition 60Bi 2 O 3 –10SrO–30Fe 2 O 3 (BSFO) (in mol%) was prepared by conventional melt quenching technique. Heat treatment process was applied to the glass samples at temperature close to crystallization temperature (600 °C) for different time intervals of 0, 2, 4 and 8, respectively, to obtain glass ceramic nano-composites. X-ray diffraction (XRD) patterns displayed the formation of a cubic Bi 3.43 Fe 0.57 O 6 for BSFO glass-ceramic nano-composites. The average nanocrystallite size (D) was determined to be between 13.48 and 17.26 nm. The values of D of the present samples were increased with an increment of heat treatment time. The high resolution-transmission electron microscope (HRTEM) images of a BSFO glass sample that was heat treated at 600 °C for 4 h show the nanocrystallites dispersed in the glass matrix with particle size in the range of 17 nm. The real part of permittivity (ε′) of BSFO decreased sharply with the increment in frequency for all samples. The decrement in the magnitude of the real part of impedance (Z′) with the increment in both frequency and temperature suggests an increase in ac conductivity σ ac. The correlated barrier hopping (CBH) model can explain the exponent S and temperature behavior we observed throughout all samples. For all glass–ceramic nano-composites, with an increase in the electric field, remnant polarization P r increases. This confirms its ferroelectric nature. The energy storage density (W r) is found to be maximum for the HT 8 h sample and equal to 34.3 mJ/cm3. The efficiency (η) of the HT 8 h sample was 65 %. The (M − H) loops of the glass–ceramic nano-composites displayed an antiferromagnetic trend. These observations suggest that the present samples might be a promising option for producing energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, Gd 2 O 3 –Ga 2 O 3 -GeO 2 -Nd 2 O 3 glasses and glass ceramics were synthesized, and their structural, thermal, and crystallization characteristics were analyzed. Our findings indicate that substituting Gd 2 O 3 for Ga 2 O 3 positively influences the enhancement of bridge oxygen content and network structure stability. Heat treatments at different temperatures showed no significant impact on the crystal phase type but did alter the crystallization rate. Optimal conditions were identified: a Gd 2 O 3 /Ga 2 O 3 ratio of 0.6 facilitated the production of transparent glass ceramics containing a single-phase GdGaGe 2 O 7 nano-crystal. Notably, the glass ceramic nucleated at 780 °C for 24 h and crystallized at 840 °C for 5 min exhibited superior performance. Despite a 6% reduction in transmission rate, the emission intensity at 1060 nm increased by 1.5 times. This material holds promise for various applications in solid-state lasers operating within the 1.06 μm region. [ABSTRACT FROM AUTHOR]

In the present work, the phase conversion of amorphous calcium phosphate (ACP) in different molten chlorides (LiCl, NaCl, KCl, CaCl 2) was investigated in detail. The main synthesis parameters influencing the phase purity and morphological features of the products include the chemical composition of molten salts, the heat treatment temperature and the ACP-to-flux ratio. The selective synthesis of single-phase Ca 5 (PO 4) 3 Cl or Ca 2 PO 4 Cl depends on the content of CaCl 2 in the reaction medium. The morphology control of Ca 5 (PO 4) 3 Cl powders was achieved by varying the KCl/CaCl 2 ratio in the flux, resulting in the formation of the particles of different size and shape. The KCl-rich fluxes led to the formation of relatively small nearly spherical particles, whereas the CaCl 2 -rich fluxes promoted an anisotropic growth of the Ca 5 (PO 4) 3 Cl crystals resulting in the formation of monodispersed hexagonally-shaped microrods. Whereas the anisotropic growth was observed at relatively low temperature (750 °C) the increase of the reaction temperature up to 1200 °C significantly reduced this effect leading to the formation of the particles with obviously low aspect ratio. The phase crystallinity and purity were analyzed using powder X-ray diffraction, FTIR spectroscopy as well as 31P, 35Cl and 1H solid-state NMR. The morphological features and chemical composition of the synthesized products were studied by SEM/EDX analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rich solvatochromic and thermochromic behavior of TPB offers new avenues for smart materials, etc. • TPB with narrowband emission is achieved, demonstrating the potential of TPB for wide colour gamut display applications. • In addition to the inorganic framework, solvent molecules also affect the luminescent properties of metal halides. The luminescent properties of metal halides are usually considered to be determined by the inorganic framework. In this work, we propose that the luminescent properties of metal halides are determined by both the inorganic framework and the solvent [Denoted as (inorganic framework + n· solvent molecules), n = 0, 1, 2...] through the abundant solvatochromic or thermochromic effect of tetrabutylammonium lead bromides [TPB, T = TBA (tetrabutylammonium), P = Pb (lead), B = Br (bromide)] containing water (H 2 O) and ethanol (EtOH). One-dimensional (1D) TPB can form ligands of [[Pb 5 Br 18 ]8− + 2H 2 O (H) ], [[Pb 5 Br 18 ]8− + 2H 2 O (H) + 2H 2 O] and [[Pb 5 Br 18 ]8− + 2EtOH] by solvent or heat treatment has completely different luminescent properties resulting from different solvents. They exhibit broad spectral emission due to strong electron-phonon coupling, as do other 1D metal halides. However, the 1D TPB containing only [[Pb 5 Br 18 ]8− achieves extremely rare narrow-band green emission, with full width at half maximum (FWHM) of 21 nm at room temperature and 8 nm at low temperature, color gamut covers 95 % of the International Telecommunication Union recommendation 2020 standard. This work provides new guidance for the modulation of photophysical properties of metal halides, as well as new materials for the display and smart materials fields. [ABSTRACT FROM AUTHOR]

Heteroatom doping can tune the band structure of semiconductors and enhance their carrier transfer capacity for improving the performance of photoelectrochemical water oxidation. Nevertheless, the introduction of dopants is not always beneficial. In this study, magnesium (Mg) is adopted to dope ZnIn2S4 nanosheet array photoanodes to form a type‐II band structure and reduce bulk recombination, but concurrently introduced deleterious oxygen (O) defects slow down the surface catalytic reaction kinetics. Furthermore, a facile heat treatment strategy is proposed to transform these O defects into Mg─O bonds. First‐principles calculations and electrochemical characterization indicate that the presence of Mg─O bonds provides abundant active sites and efficiently accelerates the surface oxygen evolution reaction by precisely realigning the rate‐determining step from OH* to O* (step 2) to OOH* to O2 (step 4), thereby retarding charge trapping and recombination. As a result, such a photoanode achieves a remarkable performance with a photocurrent as high as 4.91 mA cm−2 at 1.23 V versus reversible hydrogen electrode, and the onset potential shifts negatively about 340 mV. This work provides a new defect modulation idea for converting detrimental defects to favorable ones, and it can be expected to have wide applications in the fields of energy, catalysis, and optoelectronics, etc. [ABSTRACT FROM AUTHOR]

The study indicated that the phenolic resin pyrolysis carbon showed a gradual decrease in microdomain and domain sizes, as well as inter-domain compactness with increasing carbonization temperature (1200–1600 °C) and time (1–3 h). We determined that with an increase in carbonization temperature and time, the reduction and disappearance of organic groups such as C C, CH 2 , and C– O –C led to a gradual transformation of carbon microcrystals from structures of a larger size, with a certain curvature of more defects to smaller short straight shapes with fewer defects. This also led to a tendency of assimilation within the domains, an increase of inter-domain differences, and difficulty of further merging and growing smaller microdomains and domains. The β-SiC nanoparticles with a controllable particle size in the range of 30–200 nm, as well as controllable dispersibility, were successfully synthesized by reacting the coke with silicon. With further heat treatment at 600 °C for 6 h in air, the wrapped 2.0–3.6 nm amorphous phase homogeneous structure silicon oxide film was prepared on the SiC nanoparticles surface, which improved the oxidation resistance of the SiC nanoparticles. We determined that the reduction in microdomain and domain sizes, and an increase in inter-domain grain boundary defects, was one of the main reasons for promoting the exfoliation of microdomain and domain structures during the synthesis process to generate dispersed single smaller SiC nanoparticles. [ABSTRACT FROM AUTHOR]

The present study reveals the luminescence performance of Eu3+ doped amorphous powders derived from calcium aluminum silicate (CaAl 2 Si 2 O 8) ceramic host prepared by the combustion synthesis method assisted with urea as a fuel. The structure and phase development of the Eu3+ doped CaAlSiO material were investigated using XRD spectroscopy. The samples present an amorphous character after heat treatment at 800 °C and exhibit intense red fluorescence when stimulated by CW laser radiation at λ ∼532 nm. The excited samples displayed the emission peaks of Eu3+ corresponding to Eu3+: 5D 0 →7F J (J = 0, 1, 2, 3, 4) optical transitions, with the red emission at 613 nm originating from the 5D 0 →7F 2 transition being the most intense. Using the fluorescence intensity emissions derived from 5D 0 →7F J (J = 0, 1, 2, 3, 4) transitions, the optical intensity parameters Ω λ (λ = 2, 4) of the Eu3+ in the amorphous host were calculated. The refractive index n of the amorphous powders was also estimated in the framework of Judd-Ofelt theory. Finally, the temperature-dependent emission spectra of the CaAlSiO: (3.0 mol%)Eu3+ amorphous sample were collected in the range 298–573 K. By inspecting the fluorescence behavior of the red emission as a function of temperature, the considered phosphor was found to have high thermal stability, as evidenced by the luminous intensity maintained at around 99.2% at 423 K compared to the intensity at ambient temperature (298 K) with an activation energy of 0.34 eV. These results indicate that the Eu3+ doped CaAlSiO amorphous phase system can be potentially used for high-quality lighting applications. Finally, in order to assess the thermometric characteristics, the thermal sensing capabilities of the amorphous host have been evaluated, and the relative sensitivity, estimated by the peak-valley ratio method, was 0.23% K−1 at 298 K, validating the phosphor for temperature sensing purposes. [ABSTRACT FROM AUTHOR]

A mutual extension of an increasing demand for LiFePO 4 (LFP) is the need to develop a synthesis technique that enables improved particle morphology and size control at different scales. In this study, the polyol method was used for this purpose and modified to allow in-situ interventions, which, in turn, increased flexibility in particle design. Ethylene glycol was used as a reaction medium, and pure, porous, hierarchical LFP nanoparticles were synthesized at the lowest temperature reported in the literature. The primary and secondary particle size and morphology could be altered almost independently by controlling the amount and the addition sequence of the ascorbic acid (AA) and citric acid (CA). It was possible to control the particle features at different scales after the individual and combined effects of the acids were revealed. Particles with equiaxed small primaries (∼20 nm) and a mild aspect ratio in the secondaries (∼1.5) led to tap densities of 1.98 g/cm3, which is the highest value reported in the literature. Even though the heat treatment applied in this work had limitations in inducing a fully graphitized layer of carbon on LFPs, the added boost from the increased tap densities was observable in the high volumetric discharge capacities. [Display omitted] [ABSTRACT FROM AUTHOR]

The addition of Cr3+-oxides in a refractory provides unmatched corrosion resistance at high temperatures but generates toxic and water-soluble Cr6+ compounds, particularly in oxygen-rich and alkaline conditions. In this paper, a Cr3+ raw material (chrome-hibonite) was synthesized by the solid oxide reaction route and was used to make different calcium aluminate cement bonded alumina-based refractory castables. The castables (chrome-free and Cr3+ oxides containing) were compared regarding corrosion resistance against municipal waste slag at 1500 °C under air atmosphere. The relative Cr6+ formation within the castables containing Cr3+ oxides (Cr 2 O 3 and Ca(Al,Cr) 12 O 19) upon heat treatment at 500–1500 °C were investigated using X-ray diffraction (XRD), and Cr6+ leaching test, etc. Compared to castables without Cr3+ oxides, the corrosion resistance increases at least 5 times upon Cr3+-oxides addition, irrespective of their forms (Cr 2 O 3 or Ca(Al,Cr) 12 O 19). However, at all the tested temperatures, Ca(Al,Cr) 12 O 19 addition into the castables could suppress the Cr6+ generation significantly (below the standard solid-waste disposal limit of 3 mg/L) compared to Cr 2 O 3 , which was well above the limit. [ABSTRACT FROM AUTHOR]

Among all the cathode materials in lithium-ion batteries (LIBs), V 2 O 5 has gained a lot of attention due to its high theoretical specific capacity (∼440 mAh g−1). However, only some of the lithium-ions can be reversibly extracted after inserting into V 2 O 5 cells, making the actual reversible capacity of the crystalline V 2 O 5 cathode material much lower than its theoretical specific capacity. In this work, we prepared Li 2 O–V 2 O 5 –P 2 O 5 ternary glass by melt-quenching method. Subsequently, we grew nano-sized crystals and super-lattice structures in the glass matrix by precise heat treatment. Systematic structural, electrochemical tests and first-principles computations have shown that a reasonable amount of super-lattice structure can significantly enhance the electronic and ionic conductivity of glass matrix materials. Benefiting from this, the LVP-70-2 composite cathode exhibited excellent lithium storage performance with a stable reversible capacity of nearly ∼280 mAh g−1 at 50 mA g−1 and an outstanding cycling performance of a remaining capacity of 90 mAh g−1 at 1600 mA g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

Shape memory alloys (SMAs) represent an exceptional class of smart materials as they are able to recover their shape after mechanical deformation, making them suitable for use in actuators, sensors and smart devices. These unique properties are due to the thermoelastic martensitic transformation that can occur during both thermal and mechanical deformation. Cu-based SMAs, especially those incorporating Al and Ag, are attracting much attention due to their facile production and cost-effectiveness. Among them, Cu-Al-Ag SMAs stand out due to their notably high temperature range for martensitic transformation. In this study, a Cu-based SMA with a new ternary composition of Cu-10Al-7Ag wt.% was prepared by arc melting and the samples cut from this casting alloy were quenched in water. Subsequently, the phase composition and the development of the microstructure were investigated. In addition, the morphology of the martensite was studied using advanced techniques such as electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The analyzes confirmed the presence of martensitic structures in both samples; mainly 18R (β1′) martensite was present but a small volume fraction of (γ1′) martensite also was noticed in the as-quenched sample. The observation of fine, twinned martensite plates in the SMA alloy with symmetrically occurring basal plane traces between the twin variants underlines the inherent correlation between microstructural symmetry and the properties of the material and provides valuable insights into its behavior. The hardness of the quenched sample was found to be lower than the as-cast counterpart, which can be linked to the solutioning of Ag particles during the heat treatment. [ABSTRACT FROM AUTHOR]

In this work, the effect of heat treatment on the minority carrier lifetime (τ) in boron-doped crystalline silicon wafers coated with a silicon nitride (SiNx:H) layer has been investigated. The results showed an initial increase in τ during the early phase of light exposure of the samples, which was attributed to the presence of iron–boron complexes in the c-Si wafers. However, this enhancement was followed by a decrease associated with the formation of boron-oxygen complexes, known as light-induced degradation. Moreover, kinetic models were used to analyze defect interactions in the wafers, showing a correlation between τ behavior and hydrogen-boron complex concentrations, and related by analytical techniques. In addition, the samples were subjected to a dark annealing step, resulting in further degradation due to the firing temperature process and the presence of hydrogen atoms in the silicon nitride layer. Finally, this study provides valuable insights into defect formation mechanisms in c-Si wafers that could improve the stability and efficiency optimization of silicon-based solar cells under operating conditions. [ABSTRACT FROM AUTHOR]

The honeycomb pattern possesses a distinctive hexagonal structure capable of seamless repetition on a flat surface, leaving no gaps. Moreover, all arm thicknesses and angles are equal to one another. This remarkable configuration is deemed biomimetic, with numerous examples found in nature. Notably, it exhibits remarkably low density and exceptional mechanical strength. MAX phase films have gathered significant attention due to their exceptional capacity to amalgamate the essential properties of both metals and ceramics. Additionally, they possess the unique ability to effectively mend surface cracks that may arise as a result of friction-wear, restoring the material to a certain degree of integrity. In this study, Ti2AlN MAX phase thin films were deposited on M2 steel substrates by a closed field unbalanced magnetron sputtering system (CFUBMS). 750 °C heat treatment was applied to obtain the produced films in crystalline form. In addition, plasma etching parameters suitable for the phase structure of the deposited film were determined. With the inductive coupling plasma etching (ICP) process, the honeycomb pattern was given to the Ti2AlN MAX phase films with a continuous and smooth geometry at a depth of 2 μm. This study gives ideas for the development of multi-coating systems in which patterns of different geometries are included in a single layer. [ABSTRACT FROM AUTHOR]

Pure silicon oxide was produced in this study utilizing a sodium silicate solution made from Kankara clay as a precursor. The Kankara clay that was obtained from Nigeria was first beneficiated to produce pure dried powder clay. After that, the dried powdered clay was treated with heat activation and acid leaching, respectively. In a 500 mL Erlenmeyer flask, appropriate amounts of each clay (raw, thermally treated clay, and leached clay) were reacted with 3M NaOH solution. The flask was heated to 200°C and stirred continuously for 3 hours on a magnetic stirring hot plate connected to a reflux condenser. The solution was filtered to yield sodium silicate solution, which was then precipitated with 3M HCl while constantly stirring to produce a gelly-like white substance. The gel was aged for 18 hours, then washed with de-ionized water several times before being dried at 80°C for 12 hours to get pure white silica particles, which were subsequently described. The XRD analysis revealed that the silicon oxide synthesized is amorphous, but the microstructure evaluation revealed particles aggregation, which is usual in sol-gel synthesized powder. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to examine ingots of steel grades 35HGSL, GS-34CrMo4 and GS-42CrMo4 and to obtain data on the microstructure and mechanical properties in the cast state and after heat treatment. Based on the results, it is necessary to evaluate the effectiveness of the heat treatment used and possibly prove its justification, since this type of additional treatment is usually recommended to improve the quality of materials, but it is not mandatory, as in the present case. The economic costs of the manufacturer for conducting heat treatment can be a good solution only in the case of achieved better performance indicators of the materials, and the energy efficiency of the applied processes is essential. For all these reasons, as a result of researches will be created databases, which will give the opportunity to definite opinion on the problem. [ABSTRACT FROM AUTHOR]

Corrosion cracking is the destruction of metal under static stresses and an aggressive environment. Corrosion fatigue is destruction of the metals and the alloys under the impact of cyclic mechanical pressure and aggressive environment simultaneously. Stress corrosion is the least studied and systematized in terms of literature data on the impact of various aggressive environment (type, temperature, and concentration), composition and structure of the material, mode of heat treatment, method of obtaining and cleaning the casting, methodology for determination of corrosion under stress, as well as equipment for carrying out similar studies. The purpose of this paper is to present the methodology and equipment developed for corrosion cracking testing of cast alloys. [ABSTRACT FROM AUTHOR]

The effects of solution treatment and annealing temperature on the microstructure and mechanical properties of a new TWIP steel that was alloyed from aluminum (Al), silicon (Si), vanadium (V), and molybdenum (Mo) elements were investigated by a variety of techniques such as microstructural characterization and room tensile testing. The austenite grain size grew slowly with the increase in annealing temperature. The relatively weak effect of the solution treatment and annealing temperature on the austenite grain size was attributed to the precipitation of MC and M2C, which hindered the growth of the austenite grain. The plasticity of the TWIP steel in cold rolling and annealing after solution treatment was obviously higher than that in cold rolling and annealing without solution treatment. This was because the large-size precipitates redissolved in the matrix after solution treatment, which were not retained in the subsequently annealed structure. Through cold rolling and annealing at 800 °C after solution treatment, the prepared steel exhibited excellent strength and plasticity simultaneously, with a yield strength of 877 MPa, a tensile strength of 1457 MPa, and an elongation of 46.1%. The strength improvement of the designed TWIP steel was mainly attributed to the grain refinement and precipitation strengthening. [ABSTRACT FROM AUTHOR]

In order to ascertain the mechanical properties and fracture performance of AA6016 aluminum sheets after cold forming and heat treatment processes, uniaxial tensile tests and fracture tests were conducted under various pre-strain conditions and heat treatment parameters. The experimental outcomes demonstrated that pre-strain and heat treatment had significant impacts on both stress–strain curves and fracture properties. Pre-strain plays a predominant role in influencing the mechanical and fracture properties. The behavior of precipitation hardening under different pre-strains was investigated using Differential Scanning Calorimetry (DSC). The results indicated that pre-strain accelerates the precipitation of the β″ strengthening phase, but excessive pre-strain can inhibit the heat treatment strengthening effect. To consider the influences of pre-strain and heat treatment, a constitutive model, as well as a predictive model for load–displacement curves, was established using a backpropagation (BP) neural network. An analysis of the number of hidden layers and neuron nodes in the network revealed that the accuracy of the model does not necessarily improve with an increase in the number of hidden layers and neuron nodes, and an excessive number might actually decrease the efficiency of the machine learning process. [ABSTRACT FROM AUTHOR]