To facilitate the next generation of renewable energy devices, it is important to engineer oxygen reduction reaction (ORR) catalysts that balance efficiency and production costs. This work examines oxygen adsorption on the WC (0001) surface as a function of electrode potential, utilizing DFT simulations with an implicit solvent environment. The results demonstrate that electrode potential significantly influences oxygen adsorption energy and electronic structure. Among the adsorption sites examined, the top site exhibits the highest stability across the entire potential range. The observed reduction in adsorption energy at lower potentials is attributed to the d-band center moving further from the Fermi energy, which weakens C-O orbital interactions, as revealed by DOS and COHP analyses. Our results demonstrate the crucial role of electrochemical conditions in modulating catalytic behavior and provide valuable insights for optimizing tungsten carbide (WC)-based electrocatalysts for ORR applications.

Si2N2O combines both oxide and non-oxide properties, giving the material excellent mechanical properties and chemical stability, making it a new candidate for material improvement. This paper investigates the effect of introducing ferrosilicon nitride on the formation mechanism of in situ synthesized Si2N2O and the mechanical properties of lightweight spinel-based composites. The results show that thermodynamic calculations of the Si-NO-C system reveal the formation patterns of Si2N2O with the formation between CO and N2. Incorporating ferrosilicon nitride leads to the formation of SiC whiskers and Si2N2O at 1600 degrees C. Density functional theory (DFT) suggests that ferrosilicon nitride can reduce oxygen adsorption energy on the (200) crystal face of silicon nitride, thereby accelerating the conversion of silicon nitride to Si2N2O. Optimum mechanical properties are achieved at 0.6 wt% of ferrosilicon nitride, with cold crush strength (CCS) and cold modulus of rupture (CMOR) reaching 202.1 MPa and 29.5 MPa, respectively. At the same time, the hot modulus of rupture (HMOR) of the specimens increases by 26 % to a maximum of 16.6 MPa. After three times thermal shock cycles, the specimens show a high residual strength ratio, reaching 86 %.

β-Sialon has emerged as a promising material for enhancing the service life of Al2O3–C refractories due to its excellent physicochemical properties. The impact of varying concentrations of nanometer Al/Si alloy on the in-situ synthesis of β-Sialon within Al2O3–C refractory materials, as well as its oxidation behavior, was investigated. The findings indicate that the presence of Al/Si alloy promotes the formation of AlN and SiC whiskers at 1300 °C, which subsequently facilitate the production of plate-like β-Sialon at 1500 °C. Density functional theory analysis reveals that the (020) crystal plane of β-Sialon exhibits the lowest adsorption energy for Al2O and AlO molecules under the influence of iron atoms, suggesting a solid–liquid–vapor growth mechanism for β-Sialon formation. The introduction of these ceramic phases significantly enhances the mechanical properties of Al2O3–C refractories. Specifically, the addition of 6 wt.

This study investigates the effect of Al(OH) 3 , Mg(OH) 2 , or Ca(OH) 2 on the performance of HMC‐bonded castables (HMCC), aiming to synergistically improve the workability and medium‐temperature mechanical properties of HMCC. The results indicate that Al(OH) 3 synergistically improves the medium‐temperature mechanical properties, workability, and thermal shock resistance of HMCC. Specifically, Al(OH) 3 prolonged the setting time from 21 to 27 min, whereas Mg(OH) 2 and Ca(OH) 2 reduced it to 19 and 7 min, respectively, due to the low solubility of aluminum citrate formed by Al(OH) 3 , which inhibits HMCC ionization. Additionally, Al(OH) 3 increases the aspect ratio of hydration products, resulting in a 29.8% decrease in flowability compared with the control sample N. The addition of these compounds significantly improves medium‐temperature mechanical properties, with Al(OH) 3 increasing the cold modulus of rupture from .17 to 1.74 MPa at 500°C and from 1.24 to 2.51 MPa at 800°C. Moreover, Al(OH) 3 improves the the residual strength ratio after thermal shock from 26.16% to 28.70%, unlike Ca(OH) 2 , which lowers it to 19.02%, by enhancing resistance to microcrack propagation.

Porous SiOC ceramics have attracted considerable attention in recent years; however, a major challenge lies in the scalable fabrication of large-sized bulk materials with precisely controlled porosity and enhanced mechanical strength. In this contribution, defect-free porous SiOC bulk ceramics were successfully prepared by water-in-oil emulsion method followed by drying and pyrolysis at controlled humidity and temperatures. The effects of water and emulsifier content on the microstructure, porosity, compressive strength, and drying linear shrinkage of porous SiOC green bodies were investigated. By adjusting the amounts of oil and emulsifier, the porosity ranged from 24.98 % to 69.5 %, the average pore size varied from 13.51 mu m to 8.72 mu m, and the compressive strength decreased from 58.5 MPa to 8.17 MPa. Notably, the compressive strength of sintered specimens with a porosity of 24.98 % reached 58.5 MPa.

This study modifies the hydration process of hydrated magnesium carboxylate (HMC) by organic acids to improve the workability of HMC-bonded castables (HMCC), while comprehensively analyzing the effects of organic acids on the mechanical properties and thermal shock resistance of HMCC. Results demonstrate that lactic acid significantly increases the setting time and rheology of HMCC by 738% and 217.8%, respectively. This is due to lactic acid inhibiting HMC ionization and delaying hydration, as evidenced by hydration kinetics experiments. Furthermore, lactic acid could also reduce the degree of polymerization of HMC hydration products. Notably, lactic acid increases the cold modulus of rupture by 593.7%, 100%, and 95.7% at 500 degrees C, 800 degrees C, and 1100 degrees C, respectively. This performance improvement is attributed to lactic acid's promotion of the sintering process of HMCC, possibly due to its effect on improving castable uniformity. However, lactic acid results in an 18.1% reduction in the green body strength, potentially due to the weakened three-dimensional network structure of HMC hydration products. Additionally, lactic acid increases the residual strength ratio of HMCC by 4.3% and enhances crack propagation resistance (R & tprime;) by 45%. These improvements result from an optimized microstructure, characterized by smaller, more uniformly distributed particles with regular shapes and tighter interparticle connections.

Graphite-based composites are emerging as a new direction for the replacement of flake graphite due to their unique physicochemical properties. In this paper, aluminum source-modified graphite-based composites were prepared by using the sol-gel method, and their microstructure and wettability were investigated. The results showed that increasing the O2 partial pressure in the Al-O-C system facilitates the synthesis of Al2O3. Various iron-containing catalysts promoted the synthesis and development of Al2O3, leading to different morphologies of the Al2O3@C composites. Samples with Fe(NO3)3 as the catalyst displayed superior wettability, with the contact angle decreasing from 45 degrees to 25 degrees when the temperature is from 1200 degrees C to 1600 degrees C. Meanwhile, the samples exhibited excellent oxidation resistance after Al2O3 coating, with the minimum oxidation mass loss recorded at 20.93 %.

(3-Sialon is a candidate material for enhancing the service life of Al2O3-C refractories due to its excellent mechanical properties and high-temperature stability. In this paper, the in-situ synthesis of (3-Sialon and its effect on the mechanical properties of Al2O3-C refractories are investigated through the addition of different ironcontaining catalysts. The results indicate that within the Al-Si-O-C-N system, the controlled modulation of CO and N2 partial pressures facilitates the formation of ceramic phases, including AlN, SiC, and (3-Sialon. The introduction of three types of iron-containing catalysts can promote the formation of AlN whiskers and SiC whiskers during sintering at 1250 degrees C. At the sintering temperature of 1450 degrees C, the addition of the catalysts facilitates the generation of plate-like (3-Sialon. In particular, specimens with added ferric nitrate exhibit low apparent porosity and high bulk density of 18.1 % and 3.01 g/cm3, respectively. After calcination at 1250 degrees C and 1450 degrees C, these specimens exhibited superior mechanical properties. The cold modulus of rupture values of these specimens were 25.5 MPa and 34.8 MPa, while their cold compressive strength values were 97.2 MPa and 119.3 MPa, respectively, and their hot module of rupture values reached 12.8 MPa and 15.4 MPa, respectively. The formation of (3-Sialon endows the material with excellent thermal shock resistance, with a residual strength retention rate of 76 % after three cycles of water quenching tests.

This study investigates the effect of pre-dehydrated magnesium-silicate-hydrate (PMSH) on the properties of HMC-bonded castables (HMCC), aiming to enhance the medium-temperature mechanical performance of HMCC through the structural memory characteristics of PMSH. The results indicate that adding M-S-H-300 (PMSH treated at 300 degrees C) improves the mid-temperature mechanical properties of HMCC. Specifically, the cold modulus of rupture (CMOR) for the samples 300MSH increases by 605.9 % at 500 degrees C and 582.6 % at 800 degrees C compared to control samples due to the excellent thermal stability of M-S-H-300 and a 38.3 % improvement in castable sintering performance. Additionally, M-S-H-300 improves the thermal shock resistance and setting properties of HMCC, extending the castable's setting time by 19 %. The conductivity test results indicate that the addition of M-S-H-300 inhibits the ionization of HMC, thereby delaying its hydration process. Castables with M-S-H-300 demonstrate higher CMOR and residual strength ratio before and after thermal shock. Further testing reveals that adding M-S-H-300 increased the castable's elastic modulus by 482.6 % and fracture toughness by 35.6 % after sintering at 1500 degrees C, enhancing resistance to microcrack propagation during thermal shock. Furthermore, adding M-S-H-300 reduces the aspect ratio of HMC hydration products, optimizing microstructure and reducing porosity. However, this modification slightly decreases the mechanical properties of the green body.

Graphite-based composite materials have emerged as a crucial alternative to traditional flake graphite for optimizing the performance of Al2O3-SiC-C (ASC) castables after decarburization. In this paper, high wetting SiC@C composites powder was prepared via a sol-gel method combined with a carbothermal reduction reaction, and its effect on the oxidation behavior of ASC castables is explored. The results showed that SiC@C composites was synthesized under microwave conditions at 1000 degrees C, forming a structure where SiC whiskers are coated. And its contact angle with water decreases from 107 degrees to 35 degrees. Upon incorporation into ASC castables, the SiC whiskers within the sample continued to grow and develop with increasing addition of graphite-based composite materials. At a 2 wt% addition, the SiC whiskers began to form a cylindrical structure. Simultaneously, both the cold crushing strength and cold modulus of rupture exhibited a gradual increase. At the optimal 2 wt% addition, these values reached their maximum, 79.5 MPa and 11.4 MPa, respectively. The substitution of graphite-based composite materials also conferred good oxidation resistance to the ASC samples. Under oxidizing atmosphere conditions, the SiC whiskers on the composite material's surface facilitated the formation of a SiO2 coating layer, which impeded the contact between oxygen and graphite, thereby enhancing the oxidation resistance of the material. Consequently, the oxidation index was reduced from 75.58 % to 42.71 %.

Structural optimization of spinel based composite materials is key to improving the material of important components for purging plugs. In this paper, tabular corundum, MgAl2O4 powder, α-Al2O3 micro-powder, and silicon powder are employed as the primary raw materials in the construction of spinel-based composites, with polystyrene balls serving as a pore-forming agent and phenolic resin as a binding agent. And structural optimization and mechanical behavior of spinel based composites with addition of ferrosilicon nitride are investigated. The results show that the thermodynamic results of the Si-N-O-C system indicate that the formation of Si2N2O is primarily related to the partial pressure of CO and O2. Adding ferrosilicon nitride, SiC and Si2N2O whiskers are formed at 1600°C due to the influent of free iron. Meanwhile, the cold compressive strength and cold modulus of rupture of the specimens reach to the maximum values reach 202.1MPa and 29.5MPa at 1600°C, respectively, which the ferrosilicon nitride contents is 0.6 wt%. The force-displacement curves shows that the displacement value of specimens have a decrease tend with increasing ferrosilicon nitride. It is worth noting that the hot modulus of rupture of specimens are improved 26% when the content of ferrosilicon nitride from 0wt% to 0.6wt%. Furthermore, after three times thermal cycling, high the residual modulus of rupture and residual strength ratio of specimens are obtained. At elevated temperature 1400°C sintered, the residual modulus of rupture and residual strength ratio are higher than the specimens sintered at 1200 °C. When the addition of silicon nitride is 0.4 wt% , the residual strength ratio of specimens reaches to 82%.

With an increasing temperature gradient, the internal stress in composites can cause many problems, such as the plastic yield of the matrix, fracture of the reinforcements, growth of pores in the matrix, and debonding of the interface. The reinforcement particularly affects the internal stress, considerably changing the various properties of the composites. ZrMgMo3O12particle (p)/2024Al composites were fabricated using 5−30 vol.

The 10 vol.% ZrMgMo3O12/2024Al composites were fabricated using the powder metallurgy process and consolidation via vacuum hot pressing. The effects of the ball milling process and solution treatment time on the composites’ microstructure, Vickers hardness, and compressive properties were studied. Increasing the ball milling speed and extending the ball milling duration reduce the size of ZrMgMo3O12 particles, resulting in a more uniform dispersion within the aluminum matrix. Extending the solution treatment duration facilitates the dissolution of more primary Al2Cu phase into the aluminum matrix reducing the presence of coarse primary Al2Cu phase and increasing the number of fine Al2Cu precipitates formed during the aging process. The results indicated that an appropriate increase in ball milling speed, extension of ball milling duration, and solution treatment time can enhance the Vickers hardness and room temperature compressive strength of the composites. Specifically, the composites processed with a ball milling speed of 350 rpm for 6 h, a solid solution treatment at 495 °C for 24 h, and an aging treatment at 190 °C for 8 h exhibited a Vickers hardness of 277 HV and a compressive yield strength of 687 MPa, along with a compressive strain of 7.8 %.

With the increasing application of lithium-ion batteries, the demand for high energy density, high-rate performance and high stability lithium-ion batteries is becoming more and more urgent. Ti2CO2 MXene, as a two-dimensional material with multilayer atomic structure and multiple active sites, has great advantages in lithium-ion battery electrode materials. However, the original Ti2CO2 MXene has been unable to meet the requirements of lithium-ion batteries due to its semiconductor properties. Doping is an effective means to regulate the conductivity and electrochemical properties of Ti2CO2 and improve the capacity of lithium-ion batteries and other energy storage devices. Hence, we use first-principles calculations to study the effect of V atom doping on the adsorption and diffusion of Li on the MXene surface. The density of states (DOS) and partial density of states (PDOS) of TiVCO2 and Ti2CO2 MXene indicated the transition of their conductive types from semiconductors to conductors. In addition, we observed that TiVCO2 has higher electrical conductivity and ion transport speed than the original Ti2CO2 MXene, and at the same time, Li atoms can be adsorbed well on the surface of MXene and show a lower diffusion energy barrier. Therefore, TiVCO2 is expected to become the anode material for the next generation of lithium-ion batteries and has good lithium storage performance.

This work investigated the Vickers hardness and compressive properties of 0-30 % ZrMgMo3O12p/2024Al composites with controlled thermal expansion. The composites exhibited superior Vickers hardness and compressive properties, highly dependent on the ZrMgMo3O12 content. Under identical preparation conditions, an increase in ZrMgMo3O12 content allows for adjusting the Vickers hardness from 163 to 280 HV and the compressive yield strength from 330 to 702 MPa. Additionally, the 5 % and 10 % ZrMgMo3O12 composites exhibited 23 % and 8 % compressive strains, respectively. The Orowan strengthening effect of the ZrMgMo3O12 particles and the thermal mismatch stress at the particle-matrix interface were identified as the key strengthening mechanisms for the composites. However, excessive stress can lead to interfacial debonding and composite failure. Agglomeration of the ZrMgMo3O12 particles was observed beyond 10 % content. At 30 %, the thermal mismatch stress exceeded the binding strength, causing interfacial debonding and composite failure. The controlled mechanical properties of the 0-30 % ZrMgMo3O12p/2024Al composites indicate a promising potential for application in the aerospace and automotive industries and electronics and optical instruments sectors.

The hydrated magnesium carboxylate cement (HMC) with varying C6H5O72-/Mg2+ ratios was prepared by adjusting the ratio of citric acid to magnesia in this study, and its effect on the performances of corundum-spinel refractory castables were investigated. The results revealed that the HMC bonded castable's workability was improved by increasing the C6H5O73-/Mg2+ ratio. Specifically, the sample C-EX (citric acid/magnesia = 4.5) compared to the standard sample NO (citric acid/magnesia = 3.5), the setting time was extended by 100 min, and the flow value increased by 77.6 %. Hydration kinetics experiments demonstrate that this phenomenon was due to the excess citric acid inhibiting HMC ionization. Furthermore, increasing the C6H5O73-/Mg2+ ratio also enhanced castables' medium-temperature mechanical properties and thermal shock resistance. The excess citric acid enhanced the castable slurry's performance, resulting in a 37.8 % increase in cold modulus of rupture for the C-EX sample after sintering at 500 degrees C compared to the sample NO. The fracture strength after thermal shock is 27.9 % higher in sample C-EX than in sample NO. This improvement is attributed to the 82.1 % increase in toughness of the sample C-EX, which facilitates the micro-cracks formation but inhibits their propagation. However, it should be noted that increasing the proportion of citric acid reduced the aspect ratio of HMC hydration products, leading to decreased mechanical properties of the castables.

Previous studies have indicated that hydratable magnesium carboxylate (HMC) exhibits potential as an MgO-based binder, but its limited medium-temperature strength has hindered its widespread industrial application. In this study, the incorporation of MgO fumes into castables is intended to react with microsilica to form magnesium-silicate-hydrate (M-S-H), and the synergistic effect of HMC and M-S-H is anticipated to improve the mechanical properties of castables at intermediate temperatures. The effects of MgO fumes on the properties of HMC-bonded castables were comprehensively investigated. The results demonstrate that incorporating MgO fumes into castable serves multiple functions. The ionized MgOH+ from MgO fumes hinders the hydration process of HMC, prolonging the final setting time from 13 to 98 min and improving the workability of castables. The incorporation of MC-1100 enhanced mechanical properties at medium temperature due to the synergistic effects of brucite, HMC, and M-S-H. Specifically, the CMOR increased 20% after sintering at 800(degrees)C. Furthermore, adding MC-1100 increases the residual strength rate of castable by 10% compared to those without MgO fumes. This can be attributed to enhanced spinel formation resulting from adding MgO fumes that improves elastic modulus and reduces elastic strain energy generation during thermal shock, thus increasing crack propagation resistance.

SiC@C composites are extensively used in high-temperature metallurgy owing to their distinctive physicochemical properties. In this study, SiC@C composites with a core-shell structure were synthesized using silicon powder and Fe2O3 as the silicon source and catalyst, respectively. The effect of various temperatures on the synthesis of the SiC@C composites was investigated. The results indicated that a SiC whiskers layer covers the graphite surface at 1600 degrees C. At this temperature, the production of silicon carbide reaches 9.2 %. Transmission electron microscope (TEM) revealed that the preferred growth orientation of SiC was the (111) crystal plane. Based on density functional theory, the adsorption properties of different crystal planes of SiC crystals and their interactions with Fe atoms on the crystal surface were investigated. The results showed that the adsorption properties of different SiC crystal planes varied, with the (111) crystal plane exhibiting the strongest adsorption ability. In the presence of Fe atoms, the adsorption properties of the (111) crystal plane reaches to a value of -2686.5253 Ha, indicating that Fe atoms can promote the adsorption of other atoms or molecules on the surface of SiC crystals. Additionally, the wettability of the SiC@C composites was improved, as evidenced by the decrease in the contact angle from 109 degrees to 46 degrees.

ZrMgMo3O12 is a negative expansion material, while 2024Al alloy is a positive expansion material. The differ-ence in thermal expansion coefficients between them will cause thermal mismatch stress at the interface in ZrMgMo3O12p/2024Al composites. Therefore, the interface behaviors of ZrMgMo3O12-Al determine the prop-erties of ZrMgMo3O12p/2024Al composites to a great extent. The effects of ball milling and solid solution treatment on the microstructure and interface behaviors of 10 vol% ZrMgMo3O12p/2024Al composites were studied to improve the reticular microstructure of ZrMgMo3O12 distributed at the grain boundary of the alpha-Al matrix. The results showed that with increasing milling energy, the microstructure of the composites changed from reticular to equiaxed, and the distribution of ZrMgMo3O12 reinforcements in the matrix was more uniform. The content and size of the primary phase Al2Cu decreased with increasing solid solution treatment time. In addition, only ZrMgMo3O12-Al, Al2Cu-Al12Mo and Al-Al12Mo interfaces can be observed, but it is difficult to observe the interfaces of ZrMgMo3O12-Al12Mo in the composites milled for 12 h and solution treated for 24 h, which is related to the decomposition mechanism of ZrMgMo3O12. The decomposition mechanism is as follows: Al atoms from the alpha-Al matrix captured O atoms from ZrMgMo3O12 to form Al2O3. ZrMgMo3O12 simultaneously released Mo, Zr and Mg atoms. Mo atoms were enriched and nucleated in situ and precipitated with Al atoms to form the intermetallic compound Al12Mo, while Zr and Mg atoms entered the alpha-Al matrix to form a solid solution.