To meet the needs of low carbonization of carbon-containing refractories under the background of double carbon, Al2O3-SiC-C castables were prepared by using titanium carbide coated graphite instead of traditional spherical asphalt to solve the problem of decreased graphite content and decreased corrosion resistance caused by oxidation. The results show that the introduction of TG into the sample can reduce the increase of porosity caused by the high temperature decomposition of spherical asphalt, and optimize the matrix structure of graphite carbon network. The cold modulus of rupture and cold compressive strength of 2 wt% TG replaced spherical asphalt samples increased by 17.6 % and 27 %, respectively. At the same time, the addition of 3 wt% TG sample has a better load softening temperature, and its corrosion resistance is improved by 30.4 %. In addition, CaO-Al2O3-TiO2 high melting point compounds were formed in the sample, which increased the high temperature viscosity of the slag and inhibited the corrosion of the slag along the pores.

The exceptional properties of h-BN based ceramics are fundamental to their advancement in practical applications. The introduction of Al3BC3 into h-BN based ceramics effectively enhanced the thermal shock resistance and maintained the mechanical integrity. h-BN based ceramics were fabricated using a discharge plasma sintering process, wherein the residual flexural strength ratio of all specimens exceeded 100 R^' were examined to describe the crack initiation and propagation induced by thermal strain under steady-state heat flux, respectively. The observed improvements in residual flexural strength at elevated thermal shock temperatures can be primarily attributed to the matrix evolution through the formation of an in-situ reinforcing phase, along with the generation of Al18B4O33 whiskers via surface oxidation. At a content of 30 wt.

With the increasing global emphasis on sustainable energy, hydrogen has emerged as a promising clean energy carrier due to its high energy density and zero-carbon emissions, making it a compelling alternative to fossil fuels in the transition toward a low-carbon economy. However, the widespread adoption of water electrolysis for hydrogen production is limited by the lack of efficient, cost-effective electrocatalysts to overcome the kinetic barriers of the hydrogen evolution reaction (HER). In this context, molybdenum-based electrocatalysts-including carbides, oxides, phosphides, sulfides, and nitrides-have gained significant attention. Their noble-metal-like electronic structures make them promising candidates for HER catalysis in both acidic and alkaline electrolytes. Despite recent progress, their catalytic activity and long-term stability remain insufficient for practical applications. This review summarizes recent advances in optimizing the HER performance of molybdenum-based materials. It begins with an overview of HER mechanisms and the catalytic roles of various molybdenum compounds, followed by a detailed discussion of key structural design strategies-such as surface engineering, interface modulation, and protective coatings-that enhance catalytic performance. Finally, future directions for developing efficient, stable, and low-cost molybdenum-based catalysts for practical hydrogen production are discussed, offering theoretical insights and technical guidance for the design of nextgeneration electrocatalysts for water splitting.

To address the diminished corrosion resistance of low carbon Al2O3-C refractories resulting from reduced carbon content, this study incorporated MgSiN2 prepared by reconstructing high-silicon magnesite mineral phases into Al2O3-C refractories, and prepared samples at 1450 degrees C in an N2 atmosphere. The influence of MgSiN2 addition level on the phase composition, microstructure, mechanical properties, and corrosion resistance of the material was comprehensively explored. The findings demonstrated that MgSiN2 in-situ generated flake Mg-Sialon and granular MgAl2O4 ceramic phases, forming a three-dimensional interwoven folded network structure within the matrix, significantly boosting the aggregate-matrix interfacial bonding. When the content of MgSiN2 was 3 wt%, the porosity of the material was the lowest, and the cold modulus of rupture and cold crushing strength were the best due to the synergistic effect of the generated ceramic phases. With the increase of MgSiN2 content, the corrosion index decreased from 79.4% to 59.1%, and the corrosion resistance of the material gradually improved.

The hydrogen evolution reaction (HER) performance of a heterostructured catalyst is greatly influenced by the transport of electrons at the surface and its electronic structure at the interface's active sites. To tackle this challenge, an Ohmic-contact heterojunction electrocatalyst made from MoNi4 alloy and P-type NiO with negligible interface energy barrier has been designed. The low work function of MoNi4 nanoparticles facilitates electron transfer to NiO and constructs an Ohmic-contact between them, which effectively reduces the interface energy barrier and optimizes the electronic structure at the interface. These MoNi4 nanoparticles, with an average size of 12 nm and 10 nm apart, are uniformly and densely distributed on the NiO nanosheets, which significantly decreases surface charge transfer resistance. By combining the multiple active sites and fast hydrogen transfer, the Volmer-Heyrovsky kinetics are promoted, as confirmed by in-situ electrochemical impedance spectroscopy (EIS) along with theoretical and experimental results. As a consequence, the MoN-i4@NiO/PN electrode exhibits outstanding HER properties, including ultra-low overpotentials of 17, 63, and 329 mV at 10, 100, and 1000 mA cm-2, respectively, and a low Tafel slope of 25.9 +/- 3.8 mV dec-1, outperforming commercial Pt/C catalysts and indicating significant potential for commercial application.

Dense Al3BC3–TiB2 composite ceramics were successfully produced through spark plasma sintering at 1500 °C. The effects of TiB2 addition on the phase constituents, microstructural evolution, densification characteristics, and mechanical properties were comprehensively evaluated. XRD and TEM analyses confirmed the chemical compatibility between TiB2 and the Al3BC3 matrix. EPMA revealed a distinct Ti/Al elemental transition layer at the interface, indicating limited interdiffusion and a chemically graded interface that may help improve interfacial compatibility and bonding. Uniformly dispersed TiB2 particles effectively pinned Al3BC3 grain boundaries, inhibiting abnormal grain growth and promoting densification. The composite with 5 wt% TiB2 achieved optimal comprehensive performance with a relative density of 96.41%, a Vickers hardness of 10.39 GPa, a fracture toughness of 5.98 MPa·m1/2, and a flexural strength of 323.4 MPa. The toughening is primarily attributed to crack deflection and bridging by the TiB2 particles, while the Ti/Al interfacial transition layer synergistically enhanced the interfacial bonding strength and load-transfer efficiency. This work demonstrates that TiB2 is an effective second-phase additive for overcoming the poor sinterability and brittleness of Al3BC3 ceramics.

The poor interfacial bonding in low carbon Al2O3-SiC-C shaped refractories was effectively mitigated by in-situ ceramic bonding, greatly enhancing the mechanical properties and oxidation resistance. This study examined the influences of varying nitriding temperatures and MgSiN2 additive quantities on the mechanical characteristics and oxidation resistance of Al2O3-SiC-C refractories. The results indicated that MgSiN2 powder decomposed into Mg(g) and Si3N4(s) at a sintering temperature of 1500 degrees C. Subsequently, these decomposition products underwent phase reconstruction to form Mg-Sialon and MgAl2O4 phases. This resulted in a cold modulus of rupture of 12.10 MPa and a compressive strength of 83.60 MPa. After oxidation at 1500 degrees C in air, the formation of the Mg-Sialon phase promoted interfacial bonding between MgAl2O4 and Al6Si2O13 phases within the oxidation layer, leading to the forming of an interlocking structure. Oxidation index decreased from 75.73% to 31.33%, thereby enhancing the oxidation resistance of refractories.

The continuous accumulation of high silicon magnesite tailings pose severe challenges to the environment and resources, making effective resource utilization urgently needed. In this study, high silicon magnesite tailings were used as the main raw material, with α-Al2O3 and AlN as additives, to prepare MgAl2O4-reinforced magnesium composite refractories. The reaction mechanism of α-Al2O3 and AlN during sintering and their influence on the thermal shock resistance of the composite refractories were investigated. The results show that AlN oxidizes in air to form highly reactive Al2O3, which together with α-Al2O3 reacts with MgO to form magnesium aluminate spinel. This process is accompanied by volume expansion and N2 release, refining the grains and creating micropores at grain boundaries, thereby hindering grain boundary migration. With increasing Al addition, the spinel grains evolve from isolated distribution to a continuous rigid skeleton, changing the sintering behavior. Sample A10 with 10% Al addition exhibits the best overall performance: bulk density of 2.82 g/cm3, apparent porosity of 17.87%, compressive strength of 145.33 MPa, and flexural strength of 15.75 MPa. After thermal shock, the residual strength ratios are 76.25% and 37.52%, respectively, and the R value is 43.30. Although higher Al addition further reduces the dimensional change rate, it leads to excessive porosity and a rigid spinel skeleton, resulting in severe strength degradation and poorer thermal shock resistance. To correct the deviation of the classical thermal stress factors R′ and R″ in such composites, a power‑law compression correction (factor n = 0.3) was introduced based on Spearman numerical optimization and leave‑one‑out cross‑validation. The corrected factors R′corrected and R″corrected are consistent with the measured residual strength ratios, confirming that the proposed correction accurately reflects the actual thermal stress dissipation.

The thermal stability and selective nitridation of Ti3AlC2 in nitrogen at elevated temperatures were studied. Thermogravimetric analysis revealed a multi-stage mass gain initiating around 1243 K, indicating a reaction pathway governed by evolving microstructure. The process occurs in two distinct stages. Initially, surfacedominated nitridation forms a protective AlN layer through selective aluminum migration. This is followed by a bulk diffusion-controlled stage. The preferential migration of Al is facilitated by the relatively weak Ti-Al bonds within the MAX phase structure. Subsequently, aluminum vaporization generates interconnected micropores throughout the grains. This pore network provides enhanced pathways for gas diffusion, thereby accelerating the overall reaction. The final products are AlN and Ti(C,N) solid solutions. The reaction rate displays temperaturedependent kinetics, governed by both thermal activation and ongoing microstructural evolution. The acceleration at higher temperatures stems from two synergistic effects: increased atomic diffusion coefficients and the continuous microstructural alterations induced by aluminum vaporization.

To overcome the inherently low fracture toughness and tendency toward brittle fracture of MgSiN2 ceramics, short carbon fiber (Csf)-reinforced Csf/MgSiN2 composite ceramics were prepared by spark plasma sintering (SPS). The phase composition, microstructure, fracture behavior and elemental distribution of the composite ceramics were systematically investigated. The results showed that Csf retained its carbon-based structure and was dispersed in the MgSiN2 matrix. Continuous enrichment of Y and O along the fiber edges, together with their overlap with Mg and Si distributions, indicated the formation of a Mg-Si-Y-O-N amorphous oxynitride interphase during sintering. This interphase provided effective Csf/matrix bonding through liquid-phase wetting, oxygen-bridge bonding, and mechanical interlocking, rather than carbide-reaction bonding. During fracture, Csf not only acted as a load-bearing reinforcement but also pinned and deflected cracks and bridged crack surfaces. Local interfacial debonding, fiber pull-out, and partial fiber fracture further dissipated fracture energy, thereby improving damage tolerance.The composite containing 2 wt% Csf exhibited the best combined mechanical properties, with a room-temperature flexural strength of 430.3 MPa, a Vickers hardness of 14.2 GPa, and a fracture toughness of 6.4 MPa·m1/2, corresponding to a 41.6% increase in fracture toughness compared with the Csf-free ceramic.

To resolve severe slag penetration and erosion in Al2O3–SiC–C refractories during high scrap ratio iron ladle operation, a novel strategy utilizing exogenous MgAl2O4 spinel as a sacrificial FeOx scavenger was proposed. Al2O3–SiC–C refractories produced with plate-like corundum, silicon carbide, and flake graphite incorporating MgAl2O4 additives were cured at 1400 °C in the condition of carbon embedding. The impacts of additives on phase composition, microscopic morphology, and performance of materials were studied. The results indicated that Al2O3–SiC–C refractories with the addition of 2 wt.

To optimize the service performance of Al2O3-MgO-C refractories degraded by in-situ formation of MgAl2O4. In the present work, Al2O3-MgO-C composite refractories were prepared by adding Y2O3 as an additive. The results showed that in-situ synthesis of YAG may promote the further solid solution of aluminum ions in MgAl2O4 to produce large lattice distortion, and improve the atomic diffusion rate and diffusion path in the system to promote the densification and sintering of MgAl2O4. The YAG phase inhibits the grain boundary migration of MgAl2O4 while increasing the grain boundary density, and effectively fills the intergranular pores of MgAl2O4 and alumina particles to form a continuous matrix structure. In addition, due to the different thermal expansion coefficients of MgAl2O4 and YAG, the residual stress generates by it can offset the thermal stress cause by the change of temperature gradient, so that the thermal shock resistance of the sample with an appropriate amount of Y2O3 is improved. The corrosion resistance of the sample with Y2O3 content of 3 wt% is increased by 78.2 %. The interfacial wetting and erosion behaviors of Al2O3-MgO-C refractories in contact with ladle slag are clarified.

MgO-C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high-speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO-C refractories, as well as the mechanical properties and oxidation resistance of MgO-C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO-C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate-like Mg-Sialon and MgO-Mg2SiO4-MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation.

This paper explores the feasibility of using novel magnesia refractory raw materials, formed by reconstructing the mineral phase of low-grade magnesite, to replace traditional magnesia in MgO-C refractory. The study primarily investigates its performance at elevated temperatures. The results show that the residual strength retention rate of the refractory using the novel composite magnesia (MgO-MgSiN2) reaches 83.4 % after thermal shock cycle. At 1500 degrees C, the oxidation index of 12 wt% composite magnesia sample is 40.9 %, which is 27.1 % lower than that of traditional magnesia refractory (56.1 %), and the slag corrosion index is 40.6 %, which is 56.3 % lower than that of traditional magnesia refractory (93.0 %). This is mainly because MgSiN2 phase in the composite magnesia forms a dense layer with the matrix at high temperature, which effectively hinders the oxygen diffusion and improves the high temperature performance. The novel composite magnesia prepared from low-grade magnesite not only partially replaces the expensive traditional magnesia raw materials, reduces the production cost, effectively improves the service performance of MgO-C refractory, but also realizes the efficient recycling of magnesite waste.

Al4O4C ceramics were prepared via pressureless sintering, and the effects of Y2O3 content on their densification and mechanical properties were studied. When sintered at 1800 degrees C for 3 h, Al4O4C was identified as the major phase, while Y3Al5O12 formed as a secondary phase. The in situ YAG effectively enhanced the densification of the ceramics and contributed to the improvement in their mechanical properties. The results indicate that the optimization of Y2O3 content plays a crucial role in achieving favorable mechanical performance. Specifically, the flexural strength peaked at 197.3 MPa with 3 wt% Y2O3, while the highest Vickers hardness and fracture toughness of 14.3 GPa and 2.6 MPa center dot m1/2 were obtained with 5 wt% Y2O3. This study lays a foundation for the future research and application of Al4O4C ceramics.

The use of boron-containing additives often raises concerns when exposed to high temperatures. In this study, the high temperature stress-strain behavior and degradation mechanism of low-carbon MgO-C refractories containing TiB2-BN-AlN waste were investigated. Stress-strain curve, peak axial stress, Young's modulus, cohesion, and residual strength ratio after thermal shock tests were thoroughly analyzed. The findings suggest that the mechanical properties of refractories remain unimpaired within the temperature range of 900-1100 degrees C, and can even be enhanced through the synergistic effect of TiB2-BN-AlN waste and Al powder. The optimized axial stress increased from 55.0 to 62.0 MPa at 1100 degrees C, while the cohesion increased from 10.0 to 13.8 MPa, respectively. The observed enhancement can be primarily attributed to the effective healing of pores and cracks, reduction in oxidation, and improved material cohesion. However, the excessive incorporation of boron-containing waste may compromise the performance of refractories, leading to instability or degradation.

The present study focuses on optimizing the mechanical properties of Al4SiC4 ceramics by incorporating Y2O3 additives and utilizing spark plasma sintering. A native oxide layer, predominantly composed of Al2O3 with trace amounts of SiO2, was detected on the surface of the Al4SiC4 powder. Following sintering at 1823 K, Al4SiC4 was identified as the dominant phase, with Y3Al5O12 (YAG) recognized as the secondary phase. The effects of YAG on grain growth in Al4SiC4 is clarified based on experimental findings and molecular dynamics simulations. Additionally, the presence of SiO2 within the native oxide layer of Al4SiC4 is examined from both microstructural and thermodynamic perspectives. Precise optimization of the Y2O3 content is essential for enhancing mechanical properties, with an optimal content of 3 wt% yielding maximum values of flexural strength and fracture toughness at 436 MPa and 4.0 MPa & sdot;m1/2, respectively, along with Vickers hardness values of 12.0 GPa.

The performance stability of low-carbon Al2O3-C refractories combined with in-situ ceramics restricts their practical application. In this paper, carbon-coated corundum was prepared to adjust the distribution of in-situ ceramic phases in Al2O3-C refractories and improved the properties, and Weibull distribution function analysis was used to evaluate the reliability and stability of the mechanical properties of the modified refractory. The results demonstrated that the surface of corundum powder had a better carbon coating effect under the catalyst. Compared with the ordinary corundum powder, the introduction of catalytically modified corundum powder not only enhanced the strength of matrix-aggregate connection inside the low-carbon Al2O3-C refractories, and improved the density and stress transfer ability; but also played a positive role in enhancing mechanical reliability and stability, and the high-temperature modulus of rupture of the refractories increased by 60.36 %. The analysis and fitting of the three-parameter Weibull distribution function on the cold crushing strength results showed that the introduction of catalytically modified corundum powder increased the Weibull modulus of the refractories by 56.42 % and the critical strength by 19.53 %, indicating that the refractories had better safety and reliability in the actual use process.