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Purpose: To measure and compare the mean temperature values due to heat generated during the grinding of different prosthetic materials with diamond burs using a high-speed instrument with and without water cooling. Materials and Methods: In total, 120 disk-shaped specimens (10 × 2 mm), each with a smaller disk in the center (3 × 2 mm), were fabricated from yttrium-stabilized zirconia, monolithic zirconia, glass-ceramic, indirect composite, polyetheretherketone (PEEK), and cast metal (Ni-Cr alloy). The specimens were divided into six groups (n = 20) according to material type. The specimens in each group were ground continuously with a high-speed handpiece and diamond burs with (n = 10) and without (n = 10) water cooling until the smaller disks were removed. Two different methods (thermocouple and thermal camera) were used to measure the temperature during the grinding process. Results were analyzed using two-way ANOVA and paired-samples t test (P < .05). Results: PEEK had the lowest mean temperature and metal had the highest values, both with and without water cooling, according to data measured with a thermocouple. Zirconia and monolithic zirconia samples without water cooling had the highest mean temperature when measured with a thermal camera. Both with and without water cooling, composite samples had the lowest mean temperatures for thermal camera measurements. Conclusions: Water cooling is strongly recommended when grinding all prosthetic materials. The heat transferred to the supporting teeth may depend on the thermal conductivity of the material used. [ABSTRACT FROM AUTHOR]

Deep eutectic electrolytes (DEE) have emerged as an innovative approach to address the instability and safety issues of lithium metal batteries at elevated temperatures. However, in practice, there is often an undesirable incompatibility between the eutectic mixture and electrodes, and also an insufficient reduction stability of DEE due to the increased Li+ concentration. Herein, we designed a new DEE by utilizing weakly solvating tetrahydropyran (THP) solvent. Due to the high reduction resistance of THP and concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), this DEE demonstrates enhanced compatibility with Li metal anode and high temperature tolerance with LiMn2O4 cathode. The Li||LiMn2O4 cell (1.6 mAh cm−2) shows a high capacity retention of 96.02 % after 600 cycles at room temperature. More importantly, this Li||LiMn2O4 cell achieves a remarkable high‐temperature performance with a high capacity retention of 91.72 % after 120 cycles and low self‐discharge after storage for 240 hours at a high temperature of 55 °C, which is critical for LiMn2O4 cathode. Overall, this electrolyte design provides an alternative pathway for the development of DEEs for high‐temperature and high‐voltage lithium metal batteries, which can also be expanded to other batteries. [ABSTRACT FROM AUTHOR]

Nickel orthovanadate is a promising material with potential applications in energy storage and photocatalytic devices. The crystal structure of Ni3V2O8 at 299 (3) K and 1323 (8) K was studied using X‐ray powder diffraction. The sample was a single‐phase orthorhombic kagome‐staircase‐Ni3(VO4)2‐type structure (space group Cmca) at both temperatures. The phase purity and morphology was studied using energy‐dispersive X‐ray spectroscopy and scanning electron microscopy. The refined unit‐cell parameters at 299 (3) K are a = 5.93384 (4) Å, b = 11.38318 (7) Å and c = 8.23818 (5) Å, and at 1323 (8) K are a = 6.02077 (7) Å, b = 11.48838 (7) Å and c = 8.32611 (9) Å. The obtained results indicate thermal expansion anisotropy, with a largest expansivity along a. Variations in Ni—O and V—O bonds with temperature are observed. The variation in the Ni—O bond is about one order higher in magnitude than that of the V—O bond, signifying the high rigidity of V—O bonds. The unit‐cell size variations with rising effective ionic volume of the divalent A ion in the A3B2O8 family [A = Ni, Mg, Zn, Co, Mn (experimental data) and also A = Cu, Cd (theoretical data), B = V or As] are analyzed. Based on experimental and theoretical data, trends within the family are observed and the unit‐cell size for reported solid solution of nickel (87%) and copper (13%) mixture in (Ni1–xCux)3V2O8 are predicted. Predictions are also provided for some hypothetical A3B2O8 ternary compound and solid solutions. [ABSTRACT FROM AUTHOR]

Ni-Cu alloys are promising for application at temperatures between 400–900 °C and reducing atmospheres with high C-contents. Typically, under such conditions, metallic materials in contact with the C-rich atmosphere are degraded by a mechanism called metal dusting (MD). Ni-Cu-alloys do not form protective oxide scales, but their resistance is attributed to Cu, which catalytically inhibits the C-deposition on the surface. Adding other alloying elements, such as Mn or Fe, was found to enhance the MD attack of Ni-Cu alloys again. In this study, the effect of the Mn and Fe is divided into two affected areas: the surface and the bulk. The MD attack on binary Ni-Cu alloys, model alloys with Fe and Mn additions, and commercial Monel Alloy 400 is experimentally demonstrated. The surface electronic structure causing the adsorption and dissociation of C-containing molecules is investigated for model alloys. Analytical methods such as scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy, X-ray diffraction analysis, and near-edge X-ray absorption fine structure measurements were used. The results are correlated to CALPHAD calculations and atomistic simulations combining density functional theory calculations and machine learning. It is found that the Cu content plays a significant role in the surface reaction. The effect of Mn and Fe is mainly attributed to oxide formation. A mechanism explaining the enhanced attack by adding both Fe and Mn is proposed. [ABSTRACT FROM AUTHOR]

Conversion of CO2 and CH4 into syngas offers a promising route to reduce emissions of greenhouse gases, which facilitates large‐scale carbon fixation and boosts carbon‐neutral goal. The main obstacle for CO2/CH4 reforming is the lack of durable catalysts showing both high metal‐exposure and high‐temperature structure stability, since the reported Ni‐based catalysts have difficulty in avoiding deactivation by sintering metal at high temperature. Herein, ultra‐small Ni nanoparticles, which display multiple characteristics of high surface‐exposure and stabilized structure, are constructed from the evolution of atomically dispersed low‐valent nickel under a dually confined microenvironment. Consequently, the developed strategy can not only break the stable‐exposure trade‐off in heterogeneous catalysis but also provide new opportunity for the engineering of high‐performance and sintering‐resistant reforming catalysts as well as other durable heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

This study examined the adsorption capacities of biochars derived from kenaf (KF‐BCs) for the removal of heavy metals such as Cu(II) and Pb(II). The thermal decomposition temperature (300–750°C) significantly influenced the morphology and composition of KF‐BCs, enhancing their surface area, pore structure, and alkalinity. Among them, kenaf pyrolyzed at 750°C (KF‐750) was the most effective in removing Cu(II) and Pb(II), as validated by kinetic, equilibrium, and isotherm model analyses. Adsorption kinetics revealed that equilibrium was attained after 24 h, with chemisorption governing the process rate. Equilibrium adsorption conformed to the Langmuir and Freundlich models for Cu(II) and Pb(II), respectively. KF‐750 exhibited midrange adsorption capacities for Cu(II) and Pb(II) (23.47 ± 0.3 mg/g and 50.07 ± 0.9 mg/g, respectively), compared with the literature. The thermodynamic assessment revealed an endothermic process with positive ∆H0, indicating that higher temperatures favor metal adsorption. At low pH, adsorption decreased due to electrostatic repulsion, particularly affecting Cu(II). More than 99.8% of Cu(II) and Pb(II) were removed with a 5.00 g/L KF‐750 dose. The cation effect order on KF‐750 was Ca2+ > Mg2+ > Na+ > K+. Overall, KF‐750 demonstrates promising potential as an adsorbent for the efficient heavy metal removal from aqueous solutions, presenting a viable option for environmental remediation. [ABSTRACT FROM AUTHOR]

The reverse water‐gas shift (RWGS) reaction is significant for the resource utilization of CO2. However, this reaction requires high temperatures and metal catalysts are prone to agglomeration, leading to loss of activity. In this work, a Pt catalyst supported on Mo₂N formed via phase transition and metal reverse sintering under a high‐temperature NH₃ atmosphere is developed. This catalyst exhibits excellent RWGS activity, achieving a CO production rate of 294.8 mmolgcat−1 h−1 at 623 K, with CO selectivity maintained at 93%. Moreover, under continuous testing conditions for 100 h, the catalyst's activity shows no significant decline. Notably, further investigation reveals that the surface reaction mechanism at 623 K differs from the previously reported associative mechanism, instead following a redox mechanism in the presence of H₂. This research not only provides a deeper theoretical understanding of the mechanism of CO2 hydrogenation but also offers valuable insights for developing novel and efficient metal catalyst regeneration technologies. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon‐carbon (C−C) bonds.[1] High temperature and noble metals are usually required for depolymerization.[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter‐chain alkanes, alkenes, alcohols, and ketones (Cn, where n≲50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re‐entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth‐abundant Al2O3 was milled with reactants. [ABSTRACT FROM AUTHOR]

The dehydrogenative coupling of alcohols and amines to form amide bonds is typically catalysed by homogeneous transition metal catalysts at high temperatures ranging from 130–140 °C. In our pursuit of an efficient and recyclable photocatalyst capable of conducting this transformation at room temperature, we report herein a COF‐mediated dehydrogenative synthesis. The TTT‐DHTD COF was strategically designed to incorporate a high density of functional units, specifically dithiophenedione, to trap photogenerated electrons and effectively facilitate hydrogen atom abstraction reactions. The photoactive TTT‐DHTD COF, synthesized using solvothermal methods showed high crystallinity and moderate surface area, providing an ideal platform for heterogeneous amide synthesis. Light absorption by the COF across the entire visible range, narrow band gap, and valence band position make it well‐suited for the efficient generation of excitons necessary for targeted dehydrogenation. Utilizing red light irradiation and employing extremely low loading of the COF, we have successfully prepared a wide range of amides, including challenging secondary amides, in good to excellent yields. The substrates' functional group tolerance, very mild reaction conditions, and the catalyst's significant recyclability represent substantial advancements over prior methodologies. [ABSTRACT FROM AUTHOR]

A new N-(4-fluorobenzyl) N-(pyridin-2-ylmethyl) dithiocarbamate ligand (fbpm) having structural similarity to clinically approved antihistaminic drugs (viz. pheniramine, chlorpheniramine, and brompheniramine) and its four metal complexes [Co(fbpm)3] (1), [Ni(fbpm)2] (2), [Cu(fbpm)2] (3), and [Zn(fbpm)2] (4) were successfully synthesized and characterized by various techniques i.e. elemental analysis, FT-IR spectroscopy, HR-MS, NMR spectroscopy, and absorption and emission spectroscopy. Furthermore, complexes 1 and 2 were characterized by single crystal X-ray diffraction. Complex 1 adopts distorted octahedral geometry around the Co(III) center while complex 2 adopts distorted square planar geometry around the Zn(II) center. X-ray data also showed various weak intermolecular C–H⋯F and C–H⋯N hydrogen bonding interactions leading to supramolecular architectures in complexes 1 and 2. The thermal decomposition study of complexes 1–4 analyzed by TGA shows that they are thermally stable up to 150 °C and also gives strong evidence for the formation of respective metal sulfides at higher temperatures. The antihistaminic activity of the ligand (fbpm) and its complexes 1–4 was examined against clonidine and haloperidol-induced catalepsy in Swiss albino mice of either gender in an in vivo animal model. The result shows that these synthesized compounds have antihistaminic potential to inhibit clonidine-induced catalepsy and may be targeted for different allergic conditions. Complex 3 showed maximum reduction in clonidine-induced catalepsy after 180 minutes of treatment when compared with the induced control. [ABSTRACT FROM AUTHOR]

Coagulation is a key factor governing the size distribution of nanoclusters during the high temperature synthesis of metal oxide nanomaterials. Population balance models are strongly influenced by the coagulation rate coefficient utilized. Although simplified coagulation models are often invoked, the coagulation process, particularly for nanoscale particles, is complex, affected by the coagulating nanocluster sizes, the surrounding temperature, and potential interactions. Toward developing improved models of nanocluster and nanoparticle growth, we have developed a neural network (NN) model to describe titanium dioxide (TiO2) nanocluster coagulation rate coefficients, trained with molecular dynamics (MD) trajectory calculations. Specifically, we first calculated TiO2 nanocluster coagulation probabilities via MD trajectory calculations varying the nanocluster diameters from 0.6 to 3.0 nm, initial relative velocity from 20 to 700 m s−1, and impact parameter from 0.0 to 8.0 nm. Calculations consider dipole–dipole interactions, dispersion interactions, and short-range repulsive interactions. We trained a NN model to predict whether a given set of nanocluster diameters, impact parameter, and initial velocity would lead to the outcome of coagulation. The accuracy between the predicted outcomes from the NN model and the MD trajectory calculation results is >95%. We subsequently utilized both the NN model and MD trajectory calculations to examine coagulation rate coefficients at 300 and 1000 K. The NN model predictions are largely within the range 0.65–1.54 of MD predictions, and importantly NN predictions capture the local minimum coagulation rate coefficients observed in MD trajectory calculations. The NN model can be directly implemented in population balances of TiO2 formation. [ABSTRACT FROM AUTHOR]

Lattice structures have gained attention in engineering due to their lightweight properties. However, the complex geometry of lattice structures and the high melting temperature of metals present significant manufacturing challenges for the large-scale fabrication of these structures. Direct Energy Deposition (DED) methods, such as the Wire Arc Additive Manufacturing (WAAM) technique, appear to be an interesting solution for overcoming these limitations. This study provides a detailed analysis of the manufacturing process of carbon steel lattice structures with auxetic geometry. The study includes thermal analysis using infrared thermography, microstructural characterization through metallography, and mechanical evaluation via hardness and mechanical testing. The findings reveal the significant impact of heat input, thermal cycles, and deposition sequence on the morphology and mechanical properties of the lattice structures. Fast thermal cycles are related to areas with higher hardness values, smaller strut diameters, and porous formations, which shows that controlling heat input and heat dissipation is crucial for optimizing the properties of lattice structures produced using WAAM. [ABSTRACT FROM AUTHOR]

Although MXene has attracted great interest in diverse fields, it is susceptible to oxidation in water (H2O) with transition metal ions such as Co2+, Fe2+, and Cu2+, which is pronounced at high temperatures. This impedes the preparation of MXene‐based composites and their functional applications. Here, this study revealed that Co2+ increases the maximum and average atomic charge of H in H2O to improve the reactivity of H2O, which leads to the fact that Co2+ catalyzes the oxidation of Ti3C2Tx MXene. Furthermore, the addition of N,N‐dimethyl formamide (DMF) reduces the H2O activity and improves the oxidation stability of Ti3C2Tx in the presence of Co2+ via preferentially forming coordination bonds with Co2+. This strategy is also effective in enhancing the oxidation tolerance of Ti3C2Tx to Fe2+ in H2O. Moreover, it is feasible to enhance the oxidation stability of Ti2CTx MXene in H2O with the existence of Co2+. By virtue of these, the CoO/Ti3C2Tx composite was successfully prepared without obvious Ti3C2Tx oxidation, which is desirable to harness the advantages of Ti3C2Tx as the complementary component for lithium‐ion batteries. This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H2O in the presence of transition metal ions and at high temperatures, which opens a new vista to use MXene for target applications. [ABSTRACT FROM AUTHOR]

An unprecedented solvent-tuned electrochemical method for selective C(sp³)--H bond activation towards the synthesis of C3 functionalized chromone derivatives has been developed. This electrosynthesis protocol provides an efficient and green way to access various C3-functionalized chromones by avoiding traditionally employed transition metals and high temperatures. The swappable chemoselectivity was controlled mainly by altering the solvent and the current. A plausible reaction mechanism has been proposed with the help of radical capture and cyclic voltammetry experiments. [ABSTRACT FROM AUTHOR]

Experiments of co-gasification of spirit-based distillers' grains (SDG) and sewage sludge (SS) were carried out with red mud (RM) by using a self-designed fixed-bed gasifier. The effects of RM addition, gasification reaction temperature, SS and SDG blending ratio and other factors on the gasification reaction characteristics and synergism were investigated. The results are as follow: RM had catalytic effect on SS and SDG co-gasification, which can enhance the gasification reaction and H2 yield; increasing the temperature can enhance the gasification reaction and reduce the syngas H2/CO; with the increase of SDG, the H2 yield gradually grew; with the rise of SS, the gasification reaction gradually augmented. The catalytic mechanism was mainly due to the redox cycle of Fe2O3 in RM, which can promote the water transfer reaction. At the same time, the eutectic mixture of K, Na, Ca, Fe and other metal elements at high temperatures was the main reason for the synergistic effect. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of refractory metal on the high temperature properties of phenolic resin matrix composites, modified quartz fiber reinforced ceramizable composites were prepared by a molding process with a refractory component, tungsten, as the functional component and boron carbide as the ceramic forming agent. The effects of the tungsten and the boron carbide on the heat resistance of the composite were investigated. The results showed that the introduced refractory metal tungsten and the boron carbide can react to form tungsten borides and tungsten carbides at high temperature, and form a ceramic layer on the surface of the composite, which can fill the defects caused by pyrolysis of matrix and improve the high temperature performance of the composite. When the content of boron carbide was 10 wt% and the content of tungsten powder was 30 wt%, the flexural strength of the composite before and after heat treatment at 1200 °C were increased by 54.6% and 30.2% respectively compared with that without filler. [ABSTRACT FROM AUTHOR]

Conventional lubricants are widely used for die release as well as for cooling assistance on the die surface. However, lubrication is difficult at high temperatures. Oxidation and scaling occur on the work pieces that lead to poor surface finish and a possible warping of the material during cooling. The aim of this research is to develop self-lubricating CrAlAgN nanocomposite coatings for metal forming dies and evaluate their thermal fatigue resistance and wear behavior at elevated temperatures. The CrAlAgN coatings with different Ag contents have been deposited by plasma-enhanced magnetron sputtering. The structure and properties of the coatings were systematically studied to determine the optimal Ag content for achieving a combination of good adhesion, thermal fatigue resistance, and surface lubricity at elevated temperatures. The thermal fatigue resistance of the coatings was evaluated using thermal cyclic testing by cycling the coatings from room temperature to 800 °C up to 1200 cycles. The high temperature wear behavior of the coatings was evaluated using a tribometer up to 900 °C. Good thermal fatigue resistance and low coefficient of friction (COF) were observed in the CrAlAgN coatings with an Ag content in the range of 5–10 at. % at 800 °C. The CrAlAgN coating with 10 at. % Ag exhibited the lowest average COF of 0.05 at 800 °C. The COF of thick CrAlAgN coatings (8 at. % Ag) decreased from 0.5 to 0.2 from 500 to 900 °C, accompanied by an increase in the wear rate under more aggressive wear test conditions. The lubricity of the CrAlAgN coatings at high temperatures was attributed to the lubrication effects from the mixed oxides and encapsulated Ag diffused toward the surface. To further evaluate the coating performance, a hydraulic hot forging punch was coated with a thick CrAlAgN (8 at. % Ag) coating and evaluated in the industrial forging process. The preliminary in-plant trials demonstrated that the coating significantly reduced the dimensional distortion and wear for the forging punch. [ABSTRACT FROM AUTHOR]

Maintaining the stability of noble metals is the key to the long-term stability of supported catalysts. In response to the instability of noble metal species at high temperatures, we developed a synergistic strategy of dual oxide supports. By designing and constructing ceria components with small sizes, we have achieved unity in the ability of catalytic materials to supply oxygen and stabilize metal species. In this study, we prepared Al2O3-CeO2-Pd (AlCePd) catalysts containing trace amounts of Ce through the hydrolysis of cerium acetate, which achieved 100% CO conversion at 160 °C. More importantly, the activity remained at its initial 100% in the long-term durability testing, demonstrating the high stability of AlCePd. In contrast, the CO conversion of the CeO2-Pd (CePd) catalyst decreased from 100% to 54% within 3 h. Through comprehensive studies, we found that this excellent catalytic performance stems from the stabilizing effect of an alumina support and the possible reverse oxygen spillover effect of small-sized ceria components, where small-sized ceria components provide active oxygen for independent Pd species, making it possible for the CO adsorbed on Pd to react with this oxygen species. [ABSTRACT FROM AUTHOR]

The material undergoes high temperature and high strain rate deformation process during the cutting process, which may induce the dynamic recrystallization behavior and result in the evolution of dynamic mechanical properties of the material to be machined. In this paper, the modified Johnson-Cook (J-C) model for nickel-based powder metallurgy superalloy considering dynamic recrystallization behavior in high strain rate and temperature is proposed. The dynamic mechanical properties of the material under different strain rates and temperature conditions are obtained by quasi-static compression test and split Hopkinson pressure bar (SHPB) test. The coefficients of the modified J-C model are obtained by the linear regression method. The modified model is verified by comparison with experimental and model prediction results. The results show that the modified J-C model proposed in this paper can accurately describe the mechanical properties of nickel-based powder metallurgy superalloys at high temperatures and high strain rates. This provides help for studying the cutting mechanism and finite element simulation of nickel-based powder metallurgy superalloy. [ABSTRACT FROM AUTHOR]

Getter alloy has the advantages of low cost and high hydrogen purity in small and medium-scale hydrogen purification. However, the commonly used ZrMnFe alloy is reactive to various impurities in hydrogen, and requires a temperature above 600 °C to remove methane. To improve reactivity with methane and ensure a high hydrogen adsorption platform pressure, partial substitution of Fe with Ni, which has a smaller bonding energy with methane ligand, is beneficial. In this work, we prepared ZrMnFeNi alloys with different Ni stoichiometric ratios by suspension induction melting and investigated their performance in purifying hydrogen containing trace amounts of methane. All alloys maintain C14 Laves phase, and the interplanar spacing of the (103) crystal planes decreases with the replacement of Ni. It is proved that ZrMnFeNi alloys can significantly improve the absorb efficiency of methane in hydrogen and reduce the removal temperature. At 450 °C, ZrMnFe 0.7 Ni 0.3 can remove 10 ppm methane to 0.124 ppm. The purification efficiency of hydrogen at 450 °C can reach 96.94%, while the purification efficiency of ZrMnFe alloy is only 27.12%. The ZrMnFe 0.7 Ni 0.3 alloy decomposes methane into carbon and hydrogen during purification, and the carbon diffuses into the alloy at high temperature to form a metal carbide with zirconium. The XPS results show that the electron-rich state of Ni is more beneficial for activating the C–H bond breaking of methane. • Ni contents is optimized for the best hydrogen purification performance. • Purification temperature reduction and efficiency improvement attributed to Ni doping. • The ZrMnFe 0.7 Ni 0.3 can remove 10 ppm methane in hydrogen to 0.124 ppm at 450 °C. • Electron-rich Ni may be more conducive to the activation of C–H bond cleavage. [ABSTRACT FROM AUTHOR]

Currently green hydrogen production is attracting global attention. In this context, sustainable hydrogen production processes have been explored by using variety of materials and methods. Generation of hydrogen without CO 2 emissions is the key for carbon-free energy economy in future. Enormous amounts of scrap iron, metallurgical wastes and ferrous metals are produced in industrial processes. In this work, the reaction between metal scrap and steam is studied for hydrogen production. The scrap materials are loaded in a packed-bed reactor to produce green hydrogen by water splitting at high temperatures. This method produced 500 mL of green H 2 per gram of scrap material at 1150 °C with a conversion efficiency of about 94%. This is a potential method to utilize the scrap metals for large scale production of green hydrogen without carbon emissions. [Display omitted] • Process of hydrogen production using metal scrap. • Generation of 500 mL of green hydrogen from 1 g of waste-scrap material. • Scalable process for extracting hydrogen from metal-waste. • Maximum hydrogen concentration measured is 924 μL of hydrogen per mL of outlet gas. [ABSTRACT FROM AUTHOR]

This work follows up our previous studies dedicated to the estimation of the transient temperature of niobium and 100c6 steel samples, in ranges that include solid and liquid phases, as well as phase changes. In the experimental setup, a metallic sample of few millimeters is aerodynamically levitated and then heated by a powerful laser, while a collimator focused on the sample collects the radiative flux that is split towards five pyrometers of different wavelengths. The measured spectral fluxes are used in an inverse analysis to estimate the sample temperature. Difficulties in the inverse problem solution related to the dependence of the sample emittance with temperature and wavelength could be overcome by reducing the number of model parameters using a simple linear variation of the emittance with respect to the wavelength. In this work the transient temperature of the sample is estimated sequentially by solving a state estimation problem with two algorithms of the particle filter method, namely: the Sampling Importance Resampling (SIR) and Auxiliary Sampling Importance Resampling (ASIR) algorithms. Results obtained with these algorithms and the radiative spectral fluxes exhibited small discrepancies with respect to the temperature measurements of a reference bichromatic pyrometer. [ABSTRACT FROM AUTHOR]

3D‐printed conductive structures are highly attractive due to their great potential for customizable electronic devices. While the traditional 3D printing of metal requires high temperatures to sinter metal powders or polymer/metal composites, low or room temperature processes will be advantageous to enable multi‐material deposition and integration of optoelectronic applications. Herein, digital light processing technology and inkjet printing are combined as an effective strategy to fabricate customized 3D conductive structures. In this approach, a 3D‐printed nanoporous (NPo) polymeric material is used as a substrate onto which a nanoparticle‐based Ag ink is printed. SEM and X‐ray nano computed tomography (nanoCT) measurements show that the porous morphology of the pristine NPo is retained after deposition and annealing of the Ag ink. By optimizing the deposition conditions, conductive structures with sheet resistance <2 Ω sq−1 are achieved when annealing at temperatures as low as 100 °C. Finally, the integration of an inkjet‐printed photodetector is investigated based on an organic semiconductor active layer onto the NPo substrate. Thus, the potential of this approach is demonstrated for the additive manufacturing of functional 3D‐printed optoelectronic devices. [ABSTRACT FROM AUTHOR]

Physicists are actively debating the nature of the quantum critical phase transition that determines the low-temperature properties of metals with heavy fermions. Important experimental observations of their transport properties incisively probe the nature of the quantum critical phase transition. In our short review, we consider the transport properties of strongly correlated Fermi systems like heavy fermion metals and high— T c superconductors. Their transport properties are defined by strong inter-particle interactions, forming flat bands in these compounds. These properties do not coincide with those of conventional metals. Indeed, in contrast to the behavior of the transport properties of conventional metals, the strongly correlated compounds exhibit linear temperature resistivity ρ (T) ∝ T . We analyze the magnetoresistance and show that under the application of the magnetic field, it becomes negative. It is shown that near a quantum phase transition, when the density of the electronic states diverges, semiclassical physics remains applicable to describe the resistivity ρ of strongly correlated metals due to the presence of a transverse zero-sound collective mode, representing the phonon mode in solids. We demonstrate that when T exceeds the extremely low Debye temperature T D , the resistivity ρ (T) changes linearly with T since the mechanism of formation of the T-dependence ρ (T) is a similar electron-phonon mechanism, which predominates at high temperatures in ordinary metals. Thus, in the region of T-linear resistance, electron-phonon scattering leads to a lifetime of τ quasiparticles practically independent of the material, which is expressed as the ratio of the Planck constant ℏ to the Boltzmann constant k B , T τ ∼ ℏ / k B . We explain that due to the non-Fermi-liquid behavior, the real part of the frequency-dependent optical conductivity σ o p t R (ω) exhibits a scaling behavior and demonstrates the unusual power law behavior σ o p t R (ω) ∝ ω − 1 , rather than the well-known one shown by conventional metals, σ o p t R (ω) ∝ ω − 2 . All our theoretical considerations are illustrated and compared with the corresponding experimental facts. Our results are in a good agreement with experimental observations. [ABSTRACT FROM AUTHOR]

The recent unusual weather changes occurring in different parts of the world are caused by global warming, a consequence of the release of extreme amounts of greenhouse gases into the atmosphere. Carbon dioxide (CO2) is one of these greenhouse gasses, which can be captured and reused to generate fuel through the methanation process. Nickel- and silica-based catalysts have been recognized as promising catalysts due to their efficiency, availability, and low prices. However, these catalysts suffer from metal sintering at high temperatures. Researchers have achieved remarkable improvements through altering conventional synthesis methods, supports, metal loading amounts, and promoters. The modified routes have enhanced stability and activity while the supports offer large surface areas, dispersion, and strong metal–support interactions. Nickel loading affects the formed structure and catalytic activity, whereas doping causes CO2 conversion at low temperatures and forms basic sites. This review aims to discuss the CO2 methanation process over Ni- and SiO2-based catalysts, in particular the silica-supported Ni metal in previously reported research works and point out directions for potential future work. [ABSTRACT FROM AUTHOR]

The stress-strain constitutive law for viscoelastic materials such as soft tissues, metals at high temperature, and polymers can be written as a Volterra integral equation of the second kind with a fading memory kernel. This integral relationship yields current stress for a given strain history and can be used in the momentum balance law to derive a mathematical model for the resulting deformation. We consider such a dynamic linear viscoelastic model problem resulting from using a Dirichlet–Prony series of decaying exponentials to provide the fading memory in the Volterra kernel. We introduce two types of internal variable to replace the Volterra integral with a system of auxiliary ordinary differential equations and then use a spatially discontinuous symmetric interior penalty Galerkin (SIPG) finite element method and – in time – a Crank–Nicolson method to formulate the fully discrete problems: one for each type of internal variable. We present a priori stability and error analyses without using Grönwall's inequality and with the result that the constants in our estimates grow linearly with time rather than exponentially. In this sense, the schemes are therefore suited to simulating long time viscoelastic response, and this (to our knowledge) is the first time that such high quality estimates have been presented for SIPG finite element approximation of dynamic viscoelasticity problems. We also carry out a number of numerical experiments using the FEniCS environment (https://fenicsproject.org), describe a simulation using "real" material data, and explain how the codes can be obtained and all of the results reproduced. [ABSTRACT FROM AUTHOR]

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Metal nitrides are usually prepared by high temperature nitridation with metal oxide precursors under an NH3 atmosphere. However, owing to the differences in crystal structures between oxide precursors and nitride products, the preparation of oriented nitride nanostructures is difficult and challenging. Our previous work has demonstrated that a [100]-oriented TaON film can be fabricated by using a (012)-LiTaO3 single crystal substrate through an endotaxial transformation process. However, details about the endotaxial growth mechanism are still unclear. In this work, we systematically investigated the endotaxial growth process of TaON from the LiTaO3 single crystal substrate, and proposed a plausible growth mechanism. This work could be helpful to deepen the understanding of the unique endotaxial growth process and facilitate the fabrication of other oriented nitride nanostructures. [ABSTRACT FROM AUTHOR]

We present experimental and theoretical results on electronic structure, galvanomagnetic, and thermoelectric properties (Hall coefficient, electrical resistivity, and Seebeck coefficient) of Co 1 − x M x Si (M = Fe , Ni; x = 0 –0.1) compounds at temperatures from 80 K to 800 K. CoSi is a long known promising thermoelectric semimetal. Recently, it was shown that CoSi and the CoSi-based alloys belong to the family of materials with a topologically nontrivial electronic structure. We discuss possible connection of the observed dependences of the transport properties on temperature and alloy composition with ab initio electronic structure of the compounds. The electronic structure was calculated using density functional theory, and transport properties were analyzed in constant relaxation time, as well as in more realistic energy-dependent relaxation time approximations. [ABSTRACT FROM AUTHOR]

Yb14MnSb11 is a p-type high temperature thermoelectric material that has been shown to have a peak zT of 1.3 at 1273 K and stable lifetime testing at that temperature for over 1500 h by NASA. Yb14MgSb11 is a structural analog, but the highest temperature thermoelectric properties have not yet been reported. Yb14MgSb11 has been prepared in an environmentally friendly route employing metal hydrides to provide phase pure samples with excellent control of stoichiometry. We present a comparative study employing either MgH2 or YbH2 as a reactive precursor that also facilitates milling of the elements. High purity compositions are synthesized, and their high temperature thermoelectric properties were measured on dense pellets. Temperature-dependent thermoelectric properties were measured from 300 to 1273 K. Yb14MgSb11 exhibited a peak zT = 1.2 at 1273 K due to an appreciable power factor and low-lattice thermal conductivity. Carrier concentration and hall mobility were also measured from 300 to 1275 K and ranged from 5.3 × 1020 to 1.3 × 1021 cm−3 and from 4.7 to 0.7 cm2 V−1 S−1, respectively. [ABSTRACT FROM AUTHOR]

Yb14MnSb11 is a p-type high temperature thermoelectric material that has been shown to have a peak zT of 1.3 at 1273 K and stable lifetime testing at that temperature for over 1500 h by NASA. Yb14MgSb11 is a structural analog, but the highest temperature thermoelectric properties have not yet been reported. Yb14MgSb11 has been prepared in an environmentally friendly route employing metal hydrides to provide phase pure samples with excellent control of stoichiometry. We present a comparative study employing either MgH2 or YbH2 as a reactive precursor that also facilitates milling of the elements. High purity compositions are synthesized, and their high temperature thermoelectric properties were measured on dense pellets. Temperature-dependent thermoelectric properties were measured from 300 to 1273 K. Yb14MgSb11 exhibited a peak zT = 1.2 at 1273 K due to an appreciable power factor and low-lattice thermal conductivity. Carrier concentration and hall mobility were also measured from 300 to 1275 K and ranged from 5.3 × 1020 to 1.3 × 1021 cm−3 and from 4.7 to 0.7 cm2 V−1 S−1, respectively. [ABSTRACT FROM AUTHOR]

Promoting the activity of catalyst, achieving high CO2 conversion and increasing light olefins yield are important in CO2 hydrogenation to olefin. Herein, SiO2 was doped in CuO‐ZnO‐ZrO2 to form multi‐oxides of CuO‐ZnO‐ZrO2‐SiO2 by co‐precipitation method, and the multi‐oxides was mixed with SAPO‐34 molecular sieves mechanically to form a composite catalyst of CuO‐ZnO‐ZrO2‐SiO2/SAPO‐34. Compared with CuO‐ZnO‐ZrO2, doping of SiO2 increases the dispersion and thermal stability of metal oxides, provides more sites for CO2 activated, and delays the aggregation of metal particles at higher temperature. Doped SiO2 can also adsorb the water from hydrogenation process to improve the olefins yield and hinder the formation of CO from reverse water gas shift. Thus, under the condition of reaction temperature at 420 °C, pressure of 3.0 MPa, space velocity of 1800 mL gcat−1 h−1, CO2/H2 (molar ratio) of 1 : 3 and the mass ratio of CuO‐ZnO‐ZrO2‐SiO2 (containing 8 % SiO2) to SAPO‐34 of 1 : 1, the direct CO2 hydrogenation to light olefins on CuO‐ZnO‐ZrO2‐SiO2/SAPO‐34 shows that the conversion of CO2 is 53.9 % and the selectivity of light olefins is 52.9 %, while the CO selectivity is only 13.6 %. [ABSTRACT FROM AUTHOR]

Cermet materials exhibit advanced mechanical and tribological properties, and are widely used for tribology, elevated temperature, and machining applications due to their unique amalgamation of hardness, strength, and toughness. This paper presents a comprehensive overview of various cermet systems and recent advances in high-temperature tribology and cutting performance of cermet and ceramic tool materials. It outlines microstructural properties, such as lessening grain sizes, obtaining extended grains, lowering grain boundary phase content, amorphous grain boundary phases crystallizing, inter-granular phase strengthening, and managing crack propagation path. Additionally, surface processing or surface modifications, such as surface texturing, appropriate roughness, or coating technique, can optimize the ceramic and cermet tribological performances. The purpose of this study is to present some guidelines for the design of ceramics and cermets with reduced friction and wear and increased cutting performance. The current research progress concerning tribological properties and surface texturing of cutting tool inserts is critically identified. Lubrication techniques are required in commercial applications to increase the lifetime of cutting tools used in harsh conditions. Liquid lubricants are still commonly utilized in relative motion; however, they have the limitations of not working in extreme settings, such as high-temperature environments. As a result, global research is presently underway to produce new solid lubricants for use in a variety of such conditions. This review also provides a quick outline of current research on this topic. [ABSTRACT FROM AUTHOR]

Friction stir welding and processing (FSW/FSP) involves severe plastic deformation of metals or polymers at high temperature around a rotating tool. The material's flow is usually modelled by FEM using a complex combination of thermomechanical and friction models. However, the description of the behavior of the first atomic layers in contact with the tool cannot be undertaken by continuum mechanics modelling such as FEM. Among the available simulation techniques, molecular dynamics (MD) where friction and heat are generated by material layers' relative movement, allows the simulation of the behavior of the first atomic layers of the work piece in contact with the tool. In this work, in aluminum, the effect of temperature and advancing and rotating speeds on FSW/FSP material's flow and crystallography in the vicinity of the tool are discussed. The data analyzed demonstrate that a normalization of the weld-pitch parameter by the pin radius allows obtaining reliable heat input, momentum, and temperatures typical of this critical region in the FSW/FSP processes by MD. The results show that MD provide reliable data as an input for the FEM in a multiscale FSW/FSP modelling. [ABSTRACT FROM AUTHOR]

This study investigates the application of a metal alloy high-temperature heat pipe (HTHP) for dodecane pool burning enhancement and its corresponding heat transfer characteristics. Sodium‑potassium metal alloy with 78 % potassium weight ratio is used as the working fluid. The experiments are conducted in a 100 mm diameter pool with continuous fuel feeding for mass loss measurement. The HTHP immersion depth varies from 5 to 40 mm. The burning characteristics including flame behaviors and mass loss rate are analyzed. The maximum averaged flame height and mass loss rate are 33.2 cm and 5.3 g/min at 5 mm immersion depth, which is an increase of 48 % and 60 % respectively compared to the baseline. The lowest is at 20 mm with a 38 % and 21 % increase in flame height and mass loss rate. The cold start-up and steady state working performance of the HTHP immersed in the burning pool surface are investigated. Finally, the burning rate formulation of dodecane pool burning rate prediction is developed with the R 2 of 81.7 %. The thermal pathways coupling the effects of the HTHP dominating the liquid pool evaporation are quantitatively determined. The HTHP shows great capability of pool burning enhancement because of its energy-to-weight ratio and working reliability. [ABSTRACT FROM AUTHOR]

• 9 %Cr ODS steel with coarse grains strengthened by Cr-rich carbides and Al 2 O 3 oxides and by fine dispersion of al and Y-S c -Al nano-oxides. • The content of 1 wt.% of al supports the formation of oxide scale layer without degradation of mechanical properties of the steel. • The novel 1Al-S c -Y ODS steel suffers from lead penetration below the surface but shows promising corrosion resistance. • Pb built in the subsurface layer did not increase low LME susceptibility of the steel. Novel 1Al-S c -Y ODS Eurofer steel for use in high temperature heavy metal cooling technologies has been developed by a mechanical alloying of feedstock powders using spark plasma sintering technique and a two-step heat treatment. The 1 wt.% Al has been added to increase the resistance in the environments at high temperatures. This paper reports the microstructure and mechanical properties of the material in the as-manufactured state, and after exposure in liquid lead. Emphasis is placed on the determination of environmental resistance and namely susceptibility to cracking in contact with liquid lead. The material specimens were exposed to static liquid lead with an average concentration of oxygen 1 × 10−6 wt.% at 600 °C for 1000 h and then, tensile, impact, fracture toughness and slow three-point bend testing was performed. After the exposure, some Pb penetrated into a subsurface layer which in fact caused wetting but testing with the remains of liquid lead at the surface of corroded specimens at 350 °C showed that the steel stayed very low susceptible to the cracking. [ABSTRACT FROM AUTHOR]

Solar-driven photocatalytic water splitting for hydrogen production is gaining dramatic interests, however, efficiencies are still not satisfied to make it technically applicable in large scale. Herein, we have observed unconventional high-temperature effects on the change of intrinsic photophysical properties of semiconductors, and demonstrated dual synergistic photothermal effects in promoting hydrogen evolution from water reduction and cellulose pyrolysis at high temperature with metal oxides catalysts. Particularly, Zn/ZnO species deposited TiO 2 (Zn-TiO 2) catalyst showcased exceptional thermal-assisted photocatalytic H 2 production from water reduction along with cellulose decomposition at 573 K with quasi apparent quantum efficiency of nearly 100 % under 365±10 nm irradiation and solar to hydrogen (STH) efficiency of 2.72 %. In situ spectroscopic characterizations at 573 K corroborated that the absorption spectrum of Zn-TiO 2 could be extended into the near-infrared region (beyond 1200 nm), and electron-hole pair recombination is curbed and migration of photogenerated charge carriers within the catalyst is remarkably promoted at high temperature. In addition, experimental analysis and molecular dynamics simulations unraveled the synergistic photo-assisted thermal effects for cellulose pyrolysis, and delineated potential pathways for cellulose conversion at high temperature under light irradiation. This work paves the way for efficient utilization of whole solar spectrum for achieving sustainable water splitting and biomass waste utilization. [Display omitted] • Dual synergistic photothermal effects in promoting hydrogen evolution and cellulose pyrolysis were demonstrated. • Zn-TiO 2 showcased thermal-assisted photocatalytic H2 production at 573 K with quantum efficiency of nearly 100 %. • In situ characterizations at 573 K revealed the changes of intrinsic photophysical properties of Zn-TiO 2. • Experimental analysis and molecular dynamics simulations unraveled the synergistic effects for cellulose pyrolysis. [ABSTRACT FROM AUTHOR]

A metal-embedded fibre sensor's highest operational temperature is limited by strain due to differential thermal expansion between fibre material silica and the host metal. For a stainless steel 316 or nickel-embedded fibre sensor, it is approximately 500°C because, above this temperature, thermal strain from the host metal exceeds the tensile strength of the fibre. A novel method of attaining optical fibre sensor pre-compression inside metal for compensating the external thermal strain and achieving strain and temperature monitoring inside metal up to at least 800°C is demonstrated in this paper. The sensor shows good repeatability (error within 10°C) for the twelve temperature cycling experiments carried out after pre-compressing the fibre. Sensor response at different temperatures and external thermal strain shows good long-term stability. The highest operational temperature is limited by the fibre sensing structure (fibre Bragg grating) used in this study; using a distributed sensing interrogator can extend the operational temperature to the limits of optical fibre material with the method demonstrated in this paper. [Display omitted] • The metal-embedded sensor's max operational temperature is 500°C. • Differential thermal expansion limits the max operational temperature. • Fibre sensor pre-compression inside metal increases operational temperature range. • Demonstrated strain and temperature sensing inside metal up to 800°C. • The metal embedded sensor shows good repeatability and good long-term stability. [ABSTRACT FROM AUTHOR]

Marine equipment power systems often operate under high-temperature conditions, and metal component corrosion in high-temperature environment can lead to failure of the entire system, substantial economic losses and environmental problems. High-temperature coatings can protect metals against corrosion through thermal insulation and shielding. However, compared with a normal temperature, a high-temperature marine environment significantly exacerbates coating damage and metal corrosion. The abundance of certain chemical factors, such as the presence of chloride ions, metal ions, and undissociated organic acids and acidic pH levels, and certain biological factors, such as corrosive microorganisms and toxic substances derived from the substrate pose serious challenges for high-temperature coatings and metal protection measures. Moreover, the type of coating, preparation process and type of substrate are closely related to metal corrosion in high-temperature environments. In this review, these potential corrosion enhancement factors and corrosion mechanisms are introduced, and engineering perspectives on the control of high-temperature metal corrosion (HTMC) are provided. [Display omitted] • The synergistic factors and mechanism of HTMC in marine environment are summarized. • Compared the characteristics of metals corrosion at high and room temperatures. • Summarize the existing engineering means of HTMC prevention. • Suggestions and prospects for the development of HTMC prevention technology. [ABSTRACT FROM AUTHOR]

The purpose of this study is to prove the feasibility, efficiency and selectivity of lithium recovery from waste lithium-ion batteries (LIB) via sulfuric acid roasting-water leaching by thermodynamic analysis and experimental verification. The feasibility was proved by Gibbs free energy calculations and experiments. Then, the effects of H 2 SO 4 concentration, roasting temperature and roasting time were assessed on the leaching rate of valuable metals. The results indicate that the leaching efficiency of lithium increases firstly and then decreases with the increase of H 2 SO 4 concentration, roasting temperature and roasting time, more than 91 % lithium are leached under optimized experimental conditions: 50 wt% H 2 SO 4 , roasting temperature of 650°C, and roasting time of 2 h. Meanwhile, the selectivity of lithium is up to 88 % which means overwhelming majority lithium have been separated completely. In addition, the factors which cause sintering phenomenon such as high temperature and longtime roasting will change the microstructure of roasted product extremely, which is inconducive to the subsequent water leaching. The investigations of the phase conversion mechanism by thermodynamic simulation and instrumental characterization indicated that the leaching behaviors of valuable metals might be influenced by the different reaction pathways of the compounds while changing roasting conditions. The recovery process can be divided into two stages: the partial structure of LiNi x Co y Mn z O 2 was destroyed to form metal sulfates at ambient temperature and the solid phase reaction between unreacted LiNi x Co y Mn z O 2 which contained Li+ in the unstable layered structure with transition metal sulfates at high temperature. The fully reduced low-valence states are mainly (NiO) 0.75 (MnO) 0.25 and CoO, and basically all Li within the crystalline LiNi x Co y Mn z O 2 was de-intercalated and transformed to soluble Li 2 SO 4. These results further confirm the advantages of H 2 SO 4 roasting on selective Li recovery, and provide a better understanding of conversion mechanism by combining theory and experiments. [Display omitted] • The feasibility, efficiency and selectivity of Li recovery from waste LIB by H 2 SO 4 roasting are proved. • The overload roasting causes sintering which is inconducive to water leaching. • The mechanism of phase transformation during roasting process is revealed by simulation and characterization. • The recovery process is divided into a two-stage reaction. • Sulfuric acid roasting-water leaching process has significant economic and environmental benefits. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) plays a vital role in water splitting for renewable energy generation, making the development of cost-effective electrocatalysts essential in tackling global energy challenges. In this study, we synthesized ZIF-67@MIL-88 using a self-assembly method, with ZIF-67 serving as the precursor, followed by an aging process. The incorporation of iron-based MIL-88 significantly enhanced the surface morphology and porous structure of the catalytic material. Additionally, we prepared urchin-like CoNi@FeNi layered double hydroxides (LDHs) by etching ZIF-67@MIL-88. LDHs are known for their unique two-dimensional sheet structure and corrosion resistance. We achieved efficient OER catalytic activity through interlayer anion exchange by substituting metal cations at high temperatures. This study highlights recent advancements in the rational design of structurally unique and highly effective CoNi@FeNi-LDH composite materials using a synergistic strategy. [Display omitted] • Ni-LDH grows on the ZIF-67@MIL-88 surface, forming a novel CoNi@FeNi-LDHs catalyst. • This accelerates interfacial electron interactions, thereby improving OER kinetics. • CoNi@FeNi-LDHs hold potential for the development of electrode materials. [ABSTRACT FROM AUTHOR]

The article in Steel Research International is a guest editorial dedicated to Piotr Roman Scheller, a renowned metallurgist born in Poland in 1949. Scheller has had a distinguished career in the steel industry and academia, making significant contributions to process metallurgy and interfacial phenomena. His work has been recognized with awards and publications in reputed journals, and he continues to be active in the field even after retirement. The special issue celebrates his 75th birthday and his ongoing impact on the scientific community. [Extracted from the article]

Two-dimensional (2D) intrinsic ferromagnetic materials with large perpendicular magnetic anisotropy (PMA) and high Curie temperature have attracted extensive attention for their potential applications. However, 2D intrinsic ferromagnets prepared experimentally are still very few and most of them have low PMA and Curie temperature. Here, using first-principles calculations, we investigate the structural stability, electronic and magnetic properties of square CoSe monolayer. The calculations indicate that CoSe monolayer is ferromagnetic metal with high Curie temperature of 251.9 K and PMA of 0.825 meV/unit cell. Additionally, the effect of biaxial strain on the magnetic and electronic properties of CoSe monolayer is explored. The CoSe monolayer has strong ferromagnetism over a biaxial strain range of −5 % to 5 %. Tensile strain can induce a transition from metal to half-metal. The Curie temperature of CoSe monolayer can be enhanced under compressive strain. Tensile strain increases the magnetic anisotropy energy by 92.2 % compared with that of the unstrained system. The robust ferromagnetism as well as the regulated magnetic anisotropy and Curie temperature of CoSe monolayer provide a new direction for the development of spintronics. [ABSTRACT FROM AUTHOR]

Study of high temperatures influence on structural changes in solid structures has many drawbacks. Structure of metals is difficult to examine at the nanoscale using real experiments due to the small size of particles. In this study, we perform atomic simulations of the structural ablation caused by femtosecond laser pulses. A molecular dynamics model was built, which was used to study the structure of metals at the nanoscale level during laser ablation. [ABSTRACT FROM AUTHOR]

High temperature corrosion of metals and alloys can be controlled by the use of inhibitors and fuel additives. In this work three different types of coatings namely Y2O3, SnO2 and ZrO2 coatings were superficially applied on Ni base superalloy Superni 718. Accelerated corrosion testing of the uncoated as well as the coated superalloy was done in a molten salt environment (Na2SO4-60%V2O5) at 900°C for 50 cycles. Each cycle consisted of 1 hour heating in a Silicon Carbide Tube furnace followed by 20 minutes cooling in ambient air. Weight change measurements after each cycle were taken by an electronic balance having an accuracy of 0.01 mg. XRD, SEM and EPMA analyses of the exposed specimens were carried out to characterise the oxide scales. The bare superalloy showed more overall weight gain, in comparison with all the coated counterparts. It was concluded that ZrO2 was most effective in reducing corrosion rate in alloy A. [ABSTRACT FROM AUTHOR]

In this work, the high yield of MWNTs was prepared by chemical vapor deposition (CVD) method, followed by annealing at 2000–2800 °C, and the effects of high annealing temperature on metal impurities and defects in multi-walled carbon nanotubes (MWNTs) was explored. Furthermore, the annealed MWNTs were dispersed using a sand mill to make a conductive slurry, and finally the cathode LiNi0.5Co0.2Mn0.3O2 was added to the assembled batteries, and the application of MWNTs (slurry) as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials by sand-mill dispersion on the performance of lithium-ion batteries was investigated. The results indicate that high temperature annealing can effectively remove the residual metal impurities from MWNTs and the defects in MWNTs gradually decreases as the temperature rises. In addition, 2 wt% of MWNTs (slurry) in LiNi0.5Co0.2Mn0.3O2 is sufficient to form an electronically conductive network; as a result, the electronic conductivity and the high rates performance of the LiNi0.5Co0.2Mn0.3O2 batteries were greatly improved. The LiNi0.5Co0.2Mn0.3O2 battery with MWNTs slurries annealed at 2200 ℃ as a conductive additive displays the highest initial discharge capacity of 173.16 mAh·g−1 at 0.1 C. In addition, after 100 cycles, a capacity retention of 95.8% at 0.5 C and a discharge capacity of 121.75 mAh·g−1 at 5 C were observed. The multi-walled carbon nanotubes used as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials show excellent battery behaviors, which would provide a new insight for the development of high-performance novel conductive agents in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) can produce high‐value metallic components for many industries; however, its adoption for safety‐critical applications is hampered by the presence of imperfections. The interdependency between imperfections and processing parameters remains unclear. Here, the evolution of porosity and humps during LPBF using X‐ray and electron imaging, and a high‐fidelity multiphase process simulation, is quantified. The pore and keyhole formation mechanisms are driven by the mixing of high temperatures and high metal vapor concentrations in the keyhole is revealed. The irregular pores are formed via keyhole collapse, pore coalescence, and then pore entrapment by the solidification front. The mixing of the fast‐moving vapor plume and molten pool induces a Kelvin–Helmholtz instability at the melt track surface, forming humps. X‐ray imaging and a high‐fidelity model are used to quantify the pore evolution kinetics, pore size distribution, waviness, surface roughness, and melt volume under single layer conditions. This work provides insights on key criteria that govern the formation of imperfections in LPBF and suggest ways to improve process reliability. [ABSTRACT FROM AUTHOR]