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TiTaZrNb medium entropy coatings and their nitride forms (TiTaZrNb)Nx were synthesized by direct current magnetron sputtering. The study evaluated the bias voltage affects microstructure, chemical and phase composition of the metallic coatings. Also, the effect of nitrogen flow on the microstructural and tribological properties of the corresponding nitrides was studied. A change in the crystalline structure from BCC for TiTaZrNb coatings to FCC for (TiTaZrNb)Nx was observed. It was associated with the incorporation of nitrogen into the matrix and the consequent formation of a solid solution of (TiTaZrNb)Nx. An increase in the hardness and residual stresses of the metallic coating was observed with increasing bias voltage to − 130 V and of the nitride coating with increasing nitrogen flow to 12 sccm, reaching hardness values of 12.8 GPa and 25 GPa, respectively. A slight reduction in the hardness of the deposited nitride coating was observed at the higher nitrogen flow of 15 sccm, probably due to the formation of the TiN and ZrN phases. The higher hardness and lower wear rate of the (TiTaZrNb)Nx nitride coatings compared to the uncoated M2 steel samples demonstrate the protective effect against wear of these coatings. [ABSTRACT FROM AUTHOR]

The development of novel nitride-based phosphors is always a significant work, especially for AlON system because of their rigid crystal structure, which is similar to the promising host material of β-SiAlON. In this work, Mg2+ ion was introduced into AlON-related phase Al 5 O 3 N 3 along with co-doped Si4+ ion used to keep charge neutrality, and thus a novel Mg-based nitroaluminosilicate MgAl 3 SiO 3 N 3 (MASON) was successfully synthesized under a mild preparation condition due to the high reactivity of MgO. Benefiting from its special crystal structure optimized by the introduction of Mg2+ ion, Eu2+-activated MASON performs significant photoluminescence (PL) and cathodoluminescence (CL) properties. In contrast to most Eu2+-activated AlON related phosphors that commonly emit high-energy blue light, the as-prepared sample emits a high-bright green light along with good thermal stability. Moreover, its broad emission band with the full width at half maximum (FWHM) of 134 nm well compensates the "cyan cavity", which leads to a full spectrum light-emitting diode. The structure-property relation of Eu2+ in MASON was established in this work, which confirms the significant role of the introduced Mg2+ ion in the structure optimization of AlON system. The result may pave an efficient way to explore more promising AlON-based phosphors. High-brightness green light emission was achieved in Eu2+-activated nitroaluminosilicate MgAl 3 SiO 3 N 3. [Display omitted] [ABSTRACT FROM AUTHOR]

The nitrido‐ate complex [(PN)2Ti(N){μ2‐K(OEt2)}]2 (1) (PN−=(N‐(2‐PiPr2‐4‐methylphenyl)‐2,4,6‐Me3C6H2) reductively couples CO and isocyanides in the presence of DME or cryptand (Kryptofix222), to form rare, five‐coordinate TiII complexes having a linear cumulene motif, [K(L)][(PN)2Ti(NCE)] (E=O, L=Kryptofix222, (2); E=NAd, L=3 DME, (3); E=NtBu, L=3 DME, (4); E=NAd, L=Kryptofix222, (5)). Oxidation of 2–5 with [Fc][OTf] afforded an isostructural TiIII center containing a neutral cumulene, [(PN)2Ti(NCE)] (E=O, (6); E=NAd (7), NtBu (8)) and characterization by CW X‐band EPR spectroscopy, revealed unpaired electron to be metal centric. Moreover, 1e− reduction of 6 and 7 in the presence of Kryptofix222cleanly reformed corresponding discrete TiII complexes 2 and 5, which were further characterized by solution magnetization measurements and high‐frequency and ‐field EPR (HFEPR) spectroscopy. Furthermore, oxidation of 7 with [Fc*][B(C6F5)4] resulted in a ligand disproportionated TiIV complex having transoid carbodiimides, [(PN)2Ti(NCNAd)2] (9). Comparison of spectroscopic, structural, and computational data for the divalent, trivalent, and tetravalent systems, including their 15N enriched isotopomers demonstrate these cumulenes to decrease in order of backbonding as TiII→TiIII→TiIV and increasing order of π‐donation as TiII→TiIII→TiIV, thus displaying more covalency in TiIII species. Lastly, we show a synthetic cycle whereby complex 1 can deliver an N‐atom to CO and CNAd. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The work focuses on vertical cavity surface emitting lasers (VCSELs) made of nitride materials that emit a wavelength of 445 nm. Two structures were examined: a laser with a tunnel junction and implantation (TJ VCSEL) and an ITO contact (ITO VCSEL). The analysis delves into capacitance phenomena influencing the modulation speed of these lasers. The results highlight differences in active currents between two structures, i.e., currents which contribute to the modulation of the laser emission. According to the authors' simulations, the TJ VCSEL is more effective in modulating the number of carriers in the active region than the ITO VCSEL, assuming the same modulation amplitude of driving current. [ABSTRACT FROM AUTHOR]

UCl4, UBr4, UBr5, or UO2Cl2 reacted with excess liquid ammonia – in adventitious presence of moisture and/or air – and formed some peculiar uranium compounds of which we present the crystal structures. [(NH3)7(N3)U(μ‐O)U(NH3)8]Cl5 ⋅ 7NH3 contains a dinuclear μ‐O‐bridged uranium(IV) cation, [{(NH3)4UO2}2(μ‐O)]Cl2 ⋅ 4NH3 features a dinuclear μ‐O‐bridged uranyl(VI) cation, while the compounds [(U(VI)O2)2(U(V)O2)2(μ3‐O)2(NH3)12]Br2 ⋅ 6NH3 and [(U(VI)O2)4(U(V)O2)4(μ3‐O)4(NH3)22]Br4 ⋅ 16NH3 are mixed‐valent containing uranyl(V)‐uranyl(VI) units. For these tetra‐ and octanuclear complex cations we observed that the O atoms of the uranyl(V) units can be μ2‐ and even μ3‐bridging to uranyl(VI) units, while the O atoms of the latter are acting as terminal ligands only. [(NH3)8U(μ‐N)U(NH3)5(μ‐N)UO2(NH3)4]Br6 ⋅ 18NH3 presents the first example of a compound where the isoelectronic species UO22+ and UN2 formed a complex with the NUN unit bridging to the U atom of the uranyl(VI) cation. As it is can be difficult to distinguish between N and O atoms with X‐ray diffraction, quantum‐chemical calculations at the DFT‐PBE0/TZVP level of theory were carried out which unequivocally confirmed the atom assignments in the crystal structures. The chemical bonding in the complex cations was studied using intrinsic bonding orbitals and allowed for an additional discrimination of the U(V) and U(VI) atoms in the mixed‐valent compounds. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a detailed analysis based on both experimental and 3D modelling approaches of the unique silicon nitride precipitation sequence observed in ferritic Fe-Si alloys upon nitriding. At 570 °C, Si3N4 silicon nitride was shown to form as an amorphous phase into α-Fe ferrite matrix, which is morphologically unstable over time. Precipitates nucleated with a spheroidal shape, then developed a cuboidal shape for intermediate sizes and octapod-like morphology for a longer time. Using transmission electron microscopy, we show that the transition between spheroid and cuboid morphology depended on particle size and resulted from competition between interfacial energy and elastic strain energy. The resulting morphology was then shown to be a cuboid shape whose faces were always parallel to the {100} planes of the α-Fe; the <100> directions of the matrix corresponded to the elastically soft directions. There was a critical size of around 45 nm for which the transition between the cuboid shape and the octapod-like morphology took place. This was characterised by a transformation of quasi-flat facets into concave ones and the development of lobes in the <111> directions of the bcc crystal. To better assess the kinetic effects of diffusion fields and internal stresses on the morphological instability observed, an original 3D model that explicitly coupled phase transformations and mechanical fields was developed and applied. The latter, validated on the basis of model cases, was shown to be able to describe the time-evolution of both chemical and mechanical fields and their interactions in diffusive mass transport. Using a model system, it was shown that the concentration field around the precipitates and the internal stresses played opposing roles in the cuboid to octapod-like morphological instability. This work gives some clarification regarding the morphological evolution of amorphous Si3N4 precipitates, an important point for controlling the mechanical properties of nitrogen steels. [ABSTRACT FROM AUTHOR]

In this paper, an integrated device which realized the dual-mode integration of power amplifier (PA) and radio frequency (RF) switch based on GaN dual-gate (DG) structure is designed and fabricated. The integrated device provides two working modes and meets the performance requirements of PA and RF switch. In the transmit (Tx) mode, the integrated device is used as PA. At the frequency of 3.6 GHz, compared with the conventional GaN HEMT (high electron mobility transistor) as PA, due to the field modulation effect of the dual-gate structure, the current collapse is effectively suppressed, and the output power density $(P_{out})$ of the integrated device is increased from 6.90 W/mm to 7.85 W/mm, and the power added efficiency (PAE) is increased from 44.3% to 51.1%. In the receive (Rx) mode, the integrated device is used as RF switch. Compared with conventional RF switch, the isolation of integrated devices is significantly improved. At the frequency of 3.6GHz, the isolation is improved from 19.4 dB to 41.0 dB; At the frequency of 40 GHz, the isolation is improved from 3.0 dB to 29.7 dB. The integrated device provides a novel function integration scheme for RF frontends, with great potential for improving the integration and dimension of future communication systems.

To solve the problem of thermal stability of the red‐emitting phosphor Sr2Si5N8:Eu2+ with great valuable luminescence performance, trivalent rare earth ions Ln3+ (Ln = Dy, Ho, Er, Tm, Nd, and Pr) are co‐doped into Sr2Si5N8: Eu2+ lattice to form thermally robust phosphors Sr2Si5N8:Eu2+,xLn3+(Lnx‐258, 0 ≤ x ≤ 0.05). The successful incorporation of rare earth ions in the crystal structure and the regulation of luminescent properties are proven by a variety of material characterization techniques and analysis. Although the co‐doping of the selected rare earth ions reduces the luminescence intensity of the phosphor, the Dy0.01‐258 sample still has a high external quantum efficiency (EQE) of 78.6%. More importantly, the co‐doping of Dy3+ with x = 0.01 significantly improves the luminescent thermal stability of phosphors at high temperature and the luminescence intensity of Dy0.01‐258 samples at 200 °C can be maintained at 94.7% of room temperature. The thermoluminescence spectrum shows that the defects brought about by co‐doping of Dy3+ with x = 0.01 introduce trap energy levels, which can compensate for the Eu2+ luminescence at high temperature. At the same time, the cathodoluminescence mapping and spectra show that the phosphor has a high saturation current under high‐energy electron bombardment, which indicates that this nitride phosphor also has the potential to be used in field emission display (FEDs). Based on its extraordinary EQE and thermal stability data, this nitride phosphor is the first‐rate among the red phosphors for pc‐wLEDs, and has excellent application prospects in FEDs. [ABSTRACT FROM AUTHOR]

Alkaline hydrogen evolution reaction (HER) is suppressed by the water dissociation, leading to more sluggish kinetics than acidic HER. Developing multifunction catalysts via constructing heterogeneous interfaces is a feasible tactic to accelerate the alkaline HER. Herein, NiO coupled with Ni and MoxN (NMN) nanorods were prepared via a hydro-thermal synthesis combined with a thermal decomposition under ammonia atmosphere. The low crystalline NMN nanorods are rich in heterointerfaces, and have sufficient high active sites for HER. The synergistic effect between NiO and Ni-MoxN promotes the water dissociation the hydrogen adsorption, and the charge transfer, contributing to excellent alkaline HER activity. The overpotential on NMN is only 36 and 150 mV for the current density of 10 and 300 mA cm−2, respectively, and the Tafel slope is 48 mV/dec, demonstrating a superior performance for alkaline HER, which is even comparable to the commercial electrocatalysts.

Ti1 – xAlxN coatings with different Al content (x = 0.1–0.43) are grown on WC–Co substrates by dual high-power impulse magnetron sputtering in the Ar/N2 atmosphere. The coating resistance to high-temperature oxidation is determined. For this, the phase composition change is investigated by synchrotron radiation during heating in the air from room temperature to 1100°С. Mechanical properties (hardness, elastic modulus, plasticity index, and plastic deformation resistance) are determined by nanoindentation of coatings before and after heating to 1100°С. X-ray diffraction patterns demonstrate the formation of the TiO2 phase on the surface of all coatings, while the formation temperature and the phase type (brookite or rutile) depend on the Al content in the coating. All coatings are not subject to spinodal decomposition into the TiN and AlN phases after heating to 1100°С. The Ti0.57Al0.43N coating possesses the highest heat resistance; it undergoes the smallest change in the phase composition and mechanical properties after the high-temperature treatment. [ABSTRACT FROM AUTHOR]

Layer-by-layer deposition of zirconium and chromium nitrides is a promising material for hard coatings; however, this process is complex and not well documented in the literature. The problem lies in the difficulty of depositing thick layers of multi-component coatings with different physical characteristics, particularly the coefficient of linear thermal expansion (CLTE). As coatings undergo thermal exposure during deposition and use, different CLTEs can lead to cracking and product failure. The aim of the study is to perform on-site analysis of ZrN/CrN multilayer coatings using synchrotron radiation and investigate the micro-stress behavior of coatings deposited on a VK8 alloy substrate at temperatures up to 750°C. X-ray analysis and methods such as CLTE and qualitative determination of type II micro-stresses were used in the study. The results show changes in the characteristics of multilayer coatings during heating, the ability to determine the coefficient of thermal expansion, and qualitative determination of micro-stresses. The study provides recommendations for the application of multilayer coatings with specified characteristics. [ABSTRACT FROM AUTHOR]

Nitride wide-bandgap semiconductors possess a wide tunable energy bandgap and abundant coordination anionic groups. This suggests their potential to display nonlinear optical (NLO) properties in the UV wavelength spectrum. This paper reports recent progress and material discoveries in exploring UV NLO structures using nitrides. The study emphasizes their underlying structure–property correlations in order to provide a summary of the potential performance and application value of important nitride NLO crystals. Additionally, the text underscores the benefits of nitrides in terms of optical transparency, second-harmonic-generation effects, and the birefringent phase matching output wavelength limits, while addressing current issues in terms of theoretical outlook and experimental exploration. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride nanoparticles were successfully prepared by laser ablation in liquid. A nanosecond laser at the second harmonic of Nd:YAG was used for the preparation, and they were evaluated by scanning electron microscopy, X-ray diffraction, and dynamic light scattering. Increasing the laser fluence reduced the secondary particle size, yielding particles of 379 nm. The hightemperature laser process did not cause any phase change, and hexagonal boron nitride nanoparticles were obtained. Decreasing the amount of sodium hydroxide solution added to the solvent of laser ablation reduced the amount of agglomeration and reduced the secondary particle size, yielding nanoparticles of 189 nm. The zeta potential of the prepared nanoparticle was -62 mV and the primary particle diameter was 25 nm. [ABSTRACT FROM AUTHOR]

The influence mechanisms of Ce addition on the precipitation behaviour of σ phase and nitrides were systematically investigated. The results demonstrated that the addition of Ce significantly promoted the nucleation and slightly inhibited the growth of intergranular and intragranular σ phases. Meanwhile, Ce addition also accelerated the precipitations of π phase and Cr2N. Ce promoted the nucleation of intergranular σ phase mainly through: (i) leading to a linear increase in the driving force for σ phase and Cr activity; (ii) resulting in apparent grain refinement and providing more favorable nucleation sites. Besides increasing driving force and Cr activity, Ce addition also promoted the nucleation of intragranular σ phase by: (i) leading to lattice distortion, which not only caused local element concentration, but also reduced σ/γ interface energy, jointly increasing nucleation sites; (ii) providing other nucleation sites (Ce-bearing inclusions) for σ phase; (iii) enhancing Cr and Mo diffusion coefficients, which accelerated the supply of elements required for nucleation. Furthermore, Ce addition enhanced the driving force for Cr2N, Cr activity as well as Cr and N diffusions, and it also promoted the formation of more favorable nitride nucleation sites around σ phases. These combined actions accelerated the precipitations of π phase and Cr2N.

We present a detailed analysis based on both experimental and 3D modelling approaches of the unique silicon nitride precipitation sequence observed in ferritic Fe-Si alloys upon nitriding. At 570 °C, Si3N4 silicon nitride was shown to form as an amorphous phase into α-Fe ferrite matrix, which is morphologically unstable over time. Precipitates nucleated with a spheroidal shape, then developed a cuboidal shape for intermediate sizes and octapod-like morphology for a longer time. Using transmission electron microscopy, we show that the transition between spheroid and cuboid morphology depended on particle size and resulted from competition between interfacial energy and elastic strain energy. The resulting morphology was then shown to be a cuboid shape whose faces were always parallel to the {100} planes of the α-Fe; the directions of the matrix corresponded to the elastically soft directions. There was a critical size of around 45 nm for which the transition between the cuboid shape and the octapod-like morphology took place. This was characterised by a transformation of quasi-flat facets into concave ones and the development of lobes in the directions of the bcc crystal. To better assess the kinetic effects of diffusion fields and internal stresses on the morphological instability observed, an original 3D model that explicitly coupled phase transformations and mechanical fields was developed and applied. The latter, validated on the basis of model cases, was shown to be able to describe the time-evolution of both chemical and mechanical fields and their interactions in diffusive mass transport. Using a model system, it was shown that the concentration field around the precipitates and the internal stresses played opposing roles in the cuboid to octapod-like morphological instability. This work gives some clarification regarding the morphological evolution of amorphous Si3N4 precipitates, an important point for controlling the mechanical properties of nitrogen steels.

The parameter such as reinforced particles plays a role in controlling the microstructure and eventually influences the mechanical properties of the composite coating. The microstructure strength of composite coating come from phase combination of the matrix and its reinforcement. This study described the effect of the electrodeposition process parameters of Si3N4 particle concentration on the Ni-TiN-AlN/Si3N4 composite coatings. Therefore, the experiment was performed by varying Si3N4 particles concentration in range of 0.2, 0.4 and 0.6 g/L in electrodeposition process. The coating morphology and crystal structure were characterized by mean of Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively while the coating microhardness was tested by using Vickers hardness test. The calculations were performed to analyze the coating stress from XRD data and presented its relation with the coating microhardness. The analysis results displayed that the uniform surface morphology of composite with the evolution of nitride particle aggregation was observed at various S3N4 particles concentration. In general, the uniformity morphology was due to the refinement of Ni crystallite size. The crystal structure was noticed prominently by Ni, TiN and AlN grains while Si3N4 grain was not observed due to its amorphous nature. In general, the increase of composite microhardness, as increasing Si3N4 concentration was attributed by the reducing Ni crystallite size lead to the increase of coating residual stress. [ABSTRACT FROM AUTHOR]

(CrMoNbTaZr)NX coatings were deposited on Si (100) by magnetron sputtering under various N2/(Ar+N2) flow ratios. An X-ray diffractometer, transmission electron microscopy, scanning electron microscopy and atomic force microscopy were used to characterize the crystallinity and microstructure of the films. The elemental composition was characterized by energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The hardness and friction coefficient were respectively determined by nanoindentation and nanoscratch. The sheet resistance was studied using a four-point probe. The results suggest that the crystallinity is strongly influenced by the nitrogen content in the films. The chemical stoichiometry of nitride determines the evolutions of the microstructure, mechanical properties and resistivity. Correlations between the microstructure and the properties of the (CrMoNbTaZr)NX films were studied. [ABSTRACT FROM AUTHOR]

Preparing protecting coatings on the surface of Zr claddings has been regarded as one of the accident tolerant fuel (ATF) strategies. In this study, a series of nitride-modified layers were in situ grown by hollow cathode plasma nitriding on the surface of Zr metal. The influence of nitriding currents and time on the phases, composition, microstructure and corrosion resistance of the modified layers was investigated by X-ray diffraction (XRD), X-ray Photoemission Spectroscopy (XPS), transmission electron microscope (TEM), scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and potentiodynamic polarization curves. The ZrO2 layer with loose microstructure and cracks prefers to form under low nitriding current of 0.4 A, which also causes poor corrosion resistance. The high temperature caused by high nitriding currents (0.6 A and 0.8 A) promote the formation of compact nanocrystalline layers, made up of nitride and oxynitride. Below the nanocrystalline layer, it is Zr2N caused by N penetration. Besides this, a double-layer structure of the nanocrystalline layer, i.e., an equiaxed crystal zone with a grain size of ~10–50 nm on the surface and a long strip grain region beneath it was observed. The compact nitride/oxynitride layer with excellent interface bonding can improve the corrosion resistance effectively. [ABSTRACT FROM AUTHOR]

In this study, carbon nitride was prepared and the modification of ion doping were fulfilled by thermal polymerization method. The modified carbon nitride was employed to catalyze the electro-Fenton system to degrade phenol, and the optimal preparation conditions of the modified carbon nitride were determined as the mass ratio of doped nickel nitrate and melamine 0.55 g-10 g, the calcination temperature 500, and the calcination time 3.5 h. Applying the modified carbon nitride powder, the degradation rate of phenol in the electro-Fenton system could be increased by about 20%, and the removal rate of phenol could reach 96.7% in 30 min. In this way, the aim of catalytic degradation of phenol by modified carbon nitride without light was realized. Furthermore, the modified carbon nitride was characterized by XRD, FTIR, SEM and EDS, which proved the successful doping of Ni between carbon nitride molecules, but the molecular structure of carbon nitride was not changed; and the intermediates and possible degradation paths in the phenol degradation process were determined and analyzed by use of high performance liquid chromatography-mass spectrometry. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation is used to study the transport characteristics of NaCl solution in boron nitride nanotubes (BNNTs). It presents an interesting and well-supported MD study of the crystallization of NaCl from its water solution under the confinement of a 3 nm thick boron nitride nanotube with varied surface charging conditions. The results of the molecular dynamics simulation indicate that NaCl crystallization occurs in charged BNNTs at room temperature when the concentration of NaCl solution reaches about 1.2 M. The reason for this phenomenon is as follows: when the number of ions in the nanotubes is high, the double electric layer that forms at the nanoscale near the charged wall surface, the hydrophobicity of BNNTs, and the interaction among ions cause ions to aggregate in the nanotubes. As the concentration of NaCl solution increases, the concentration of ions when they aggregate in the nanotubes reaches the saturation concentration of the NaCl solution, resulting in the crystalline precipitation phenomenon. [ABSTRACT FROM AUTHOR]

The variation in crystallinity, morphology and phase of zinc tin hydroxide nanostructures are investigated after annealing at different (oxidizing, non-oxidizing and reducing) atmospheres. The zinc tin hydroxide nanostructures are prepared using hydrolysis assisted co-precipitation method. Annealing in oxidizing (oxygen and air) and non-oxidizing (nitrogen and argon) atmospheres do not have a significant effect on morphological and structural properties. However, the annealing in the reducing (ammonia) atmosphere converts the cubic nanostructures into nanorods and spherical particles. The zinc tin hydroxide forms three new phases (ZnON, SnO 2 and Sn) after annealing in reducing atmosphere. The formation of ZnON and SnO 2 phases are evident in Raman and XPS analysis. The reducing atmosphere (ammonia) changes the reaction kinetics leading to diffusion control crystal growth that could be responsible for such structural and morphological transformation. The bandgap is significantly changed after morphological and structural transformation with notable variation in photocurrent density, charge transfer resistance, and charge carrier concentration. [ABSTRACT FROM AUTHOR]

The currently known main mechanisms of martensitic transformation of austenite in steel during cooling, physical models, and schemes of shear rearrangement of the iron crystal lattice during γ→α transformation under the action of internal stresses are considered. An analysis of the available kinetic model of the shear transformation of austenite in steel is carried out considering the influence of stresses. As shown, for the transformation of retained austenite into martensite, two main conditions have to be fulfilled. The first one is thermodynamic condition due to decreasing the temperature of the steel down to the temperature of the end of the transformation of retained austenite. The second condition is kinetic one due to increasing the level of internal stresses in austenite, the cooling rate at the final treatment stage or mechanical impact. To calculate the effect of stresses on the transformation of retained austenite in steel, a new equation is proposed that takes into account the minimum stress required for a crystallogeometrically ordered displacement of iron atoms during the formation of martensite. As shown, the effect of alloying elements and cooling rate on the temperature of the beginning and end of the austenite transformation can be calculated using the relations given in the article. To calculate the quantity of martensite formed depending on the transformation temperature, an improved Koistinen–Marburger equation is suggested. This equation takes into account not only the temperature of the beginning, but also the temperature of the end of the austenite transformation, i.e., increases the accuracy of the obtained result.

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

This study investigated the combustion synthesis of an Eu,Si-doped AlN blue phosphor for white light emitting diodes (LEDs) using Al, AlN, Eu2O3 and Si3N4 powders as raw materials. The photoluminescence (PL) property, crystal structure, and location of Eu of the synthesized phosphor were studied. When Eu is doped without Si doping, Eu does not locate into the AlN crystal but exists at the grain boundary as an oxide. When Eu and Si are co-doped, the Si-Eu-O rich layer generates in the AlN crystal, which exhibits the blue emission under ultraviolet irradiation. Eu is doped as divalent cations in the crystal and the large distance between Eu and surrounding ligands might reduce the crystal field splitting, resulting in the blue emission. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

The separation of rare earth elements from the mining waste water is highly important but still facing challenge. In this study, three different porous composite electrode materials were well-designed by decorating the nickel‑iron bimetallic oxide, nitride or phosphide onto nitrogen-doped carbon nanosphere, respectively (termed as NiFeO@NC, NiFeN@NC and NiFeP@NC), and utilized in capacitive deionization device for electrosorption of Yb(III) from water under the low-voltage electric field. The characterization and electrochemical results indicated that the incorporation of N or P atom lead to the reduced specific surface area and the enhanced electrochemical properties (i.e., larger specific capacitance, lower charge transfer resistance). In addition, NiFeN@NC and NiFeP@NC exhibited the excellent electrosorption capacities of Yb(III) with 105.24 mg·g−1 and 90.31 mg·g−1, respectively, under conditions of a flow rate of 20 mL·min−1, a voltage of 1.2 V, and pH of 5.0, which was extremely higher than NiFeO@NC (i.e., 50.7 mg·g−1). Moreover, all these three materials also demonstrated the remarkable electrosorption selectivity of Yb(III) from the mixed solution, and the robust durability with over 90 % of initial capacities after ten consecutive electrosorption-desorption cycles. Furthermore, the XPS characterizations and electrosorption results revealed that the electrosorption mechanism mainly depended on the synergistic effects of intrinsic Faraday redox reaction, electric double layer capacitance and active binding sites. Therefore, this work provided a feasible strategy for the separation of rare earth elements from aqueous solution, and the prospective applications related to the recovery of rare earth elements from mining wastes or spent permanent magnets in future life. • Novel NiFeO@NC, NiFeN@NC and NiFeP@NC are designed and fabricated. • Electrosorption of Yb(III) by three electrode materials are comparatively studied. • Mechanism depends on electric double layer, pseudo-capacitance, active sites. • Electrodes exhibit remarkable reusability for 10 times and excellent selectivity. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is an unavoidable element in single-crystal superalloys that combines with other elements to form nitrides. Large-size nitrides often become the sites of crack initiation and propagation, which adversely affect the microstructures and mechanical properties of superalloys. However, in this study, it was found that the addition of trace amounts of N could improve the creep properties of superalloys. The results indicated that the size and number of nitrides gradually increased as the N contents increased from 3 ppm to 25 ppm. In addition, the porosity first decreased and then increased. The cause of the increase and subsequent decrease in creep lives as N contents increased was the lattice expansion caused by the formation of nitrides, which reduced the porosity by compensating for volume contraction. Meanwhile, the small-size nitrides could impede dislocation movement, which benefited the creep life of the specimens, resulting in the best creep life of the specimens containing 12 ppm of N. • The effect of N content on nitrides was investigated. • The mechanism of small-size impeding dislocation motion was confirmed. • The mechanism of the effect of N content on micropores was revealed. • The N content-nitride-porosity relationship was revealed. [ABSTRACT FROM AUTHOR]

Nitride wide-bandgap semiconductors possess a wide tunable energy bandgap and abundant coordination anionic groups. This suggests their potential to display nonlinear optical (NLO) properties in the UV wavelength spectrum. This paper reports recent progress and material discoveries in exploring UV NLO structures using nitrides. The study emphasizes their underlying structure–property correlations in order to provide a summary of the potential performance and application value of important nitride NLO crystals. Additionally, the text underscores the benefits of nitrides in terms of optical transparency, second-harmonic-generation effects, and the birefringent phase matching output wavelength limits, while addressing current issues in terms of theoretical outlook and experimental exploration.

A high-speed and high-power current measurement instrument is described for measuring rapid switching of ferroelectric samples with large spontaneous polarization and coercive field. Instrument capabilities (±200 V, 200 mA, and 200 ns order response) are validated with a LiTaO3 single crystal whose switching kinetics are well known. The new instrument described here enables measurements that are not possible using existing commercial measurement systems, including the observation of ferroelectric switching in large coercive field and large spontaneous polarization Al0.7Sc0.3N thin films. [ABSTRACT FROM AUTHOR]

Evolution of nitrogen (N), a life-essential volatile element, in highly reduced magmatic systems is a key for the origin of N on rocky planets formed via accretion of reduced chondritic parent body materials, planetesimals, and embryos that underwent partial or complete differentiation. However, the storage capacity of N in phases relevant for reduced silicate systems undergoing thermal processing is poorly known. To investigate the stability of N -bearing phases in partially molten silicate-rich systems as well as solubility of nitrogen in silicate melts and minerals, we performed laboratory experiments on a 80:20 synthetic basalt-Si 3 N 4 mixture at 1.5–3.0 GPa and 1300–1600 °C in graphite capsules, yielding oxygen fugacity ranging from ∼ IW– 3.0 to ∼ IW – 4.0. All experiments produced silicate melt + nierite + Fe-rich alloy melt + N -rich vapor ± sinoite ± cpx. Sinoite was restricted to above while cpx was restricted below 1400–1500 °C. Nitrogen solubility and Nitrogen Concentration at Silicon-Nitride Saturation (NCNS) in silicate melts increase with increasing pressure and temperature and range between 3.6 and 9.5 wt%. Using our high pressure N solubility data and similar data at ambient and lower pressures, we derived a new N solubility model in silicate melts. Solubility of nitrogen in cpx was between 1.51 and 2.05 wt% and resulted in cpx/silicate melt partition coefficients for nitrogen, D N c p x / s i l i c a t e m e l t of ∼ 0.4 to ∼ 0.2. These D N c p x / s i l i c a t e m e l t are distinctly higher than those previously estimated at more oxidizing conditions, suggesting N maybe much less incompatible during thermal processing of rocky reservoirs at highly reducing conditions. Partition coefficient of N between Fe-rich alloy melt and cpx, D N F e - r i c h a l l o y m e l t / c p x was found to be between 1.6 and 2.1. The application of our N solubility data and model suggests that mobilization of N from the deeper, partially molten reservoirs to shallower reservoirs is possible in reduced planetesimals and internally differentiated meteorite parent bodies – leading to net loss of N via melt degassing or reprecipitation of N -bearing solid phases, depending on whether the surficial shell is oxidized or reduced, respectively. Similarly, comparison of the first measured D N c p x / s i l i c a t e m e l t values from our highly reducing experiments with those estimated at more oxidizing conditions suggest that N would be much less incompatible during internal and external magma ocean processing of rocky bodies under highly reducing conditions. Therefore, enrichment of N in the atmospheres of Earth and Venus is likely a result of more oxidizing penultimate phase of accretion, which would lead to N being more readily partitioned to residual liquid, which would also more readily degas at oxidizing conditions. [ABSTRACT FROM AUTHOR]