In this study, vacuum impregnation was employed to modify the surface of spherical zircon aggregates with alumina sol. Experimental results demonstrated that the incorporation of alumina sol transformed the initially homogeneous aggregate structure into a core-shell architecture, wherein the core consisted of zircon and the shell was composed of mullite. Specifically, the introduced Al2O3 accelerated the decomposition of zircon; the SiO2 generated from this decomposition then underwent an in-situ reaction with Al2O3 to form mullite. The structural modification not only enhanced the sintering behavior of the aggregates but also improved overall performance. Additionally, the formation of mullite structure on the aggregate surface further contributed to the performance enhancement of zircon aggregates. After undergoing the surface modification, the zircon aggregates exhibited a marked reduction in apparent porosity alongside a high cylinder compressive strength retention rate; these favorable performance characteristics were conducive to the practical utilization in the fabrication of refractories.

This study systematically investigated the differences in mechanical properties, slag corrosion resistance, and oxidation resistance of MgO-C refractories incorporated with two types of anti-oxidants, namely silicon (Si, labeled as S) and silicon carbide (SiC, labeled as SC) powders. The corrosion characteristics of MgO-C refractories exposed to slags with low basicity were also analyzed. After high-temperature heat treatment at varied temperatures, sample SC possessed higher mechanical strength than sample S. Owing to the relatively low oxidation rate of SiC powder, sample SC presented inferior oxidation resistance and a wider transition zone. In addition, the reaction between Si powder and graphite led to the formation of a porous microstructure in the matrix. Consequently, the matrix of sample S suffered severe slag erosion and structural damage. Overall, sample SC exhibited superior resistance to slag penetration and corrosion compared with sample S. Thermodynamic simulation results revealed that slag basicity regulated the content and viscosity of the liquid phase generated during high-temperature reactions, which further caused distinct differences in the slag penetration resistance of the two refractories. Notably, sample SC achieved the optimal slag penetration resistance at a slag basicity of 1.5.

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.

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.

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.

(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.

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%.

Oil-water separation by gravity has been introduced as an effective water purification technique. However, traditional materials such as metal mesh and polymer braid are challenging to utilize in harsh water environ-ments. In this work, ceramic fiber braids with excellent chemical and thermal stability were fabricated and used for oil-water separation. Needle-like mullite whiskers with length of similar to 100 nm was in-situ grown on the surface of the fibers using gas phase reaction which could significantly increase the surface roughness of ceramic fibers. The ceramic fiber was successfully converted to hydrophobic structure with water contact angle of 159.4 degrees +/- 1.9 degrees and sliding angle of 8.8 degrees +/- 2.0 degrees. The excellent structural stability and oil water separation performance confirm the wide range applications of the hydrophobic ceramic fiber braids in harsh water environments.

Ultra-high temperature ceramic coatings have ultra-high melting points,excellent mechanical properties and high temperature ablation resistance.These unique performance combinations turn it into a promising material for use in extreme environment structures in rockets and hypersonic vehicles,particularly nozzles,leading edges and engine components.In this paper,various preparation methods of ultra-high temperature ceramic coatings were reviewed,including plasma spraying,chemical vapor deposition,pack cementation,slurry sintering,hot pressing and their research progress.Meanwhile,some new preparation methods of high temperature coatings,such as ion beam deposition,ultrasonic spraying,metal organic frame work coating,and magnetron sputtering,were introduced.The development trend of ultra-high temperature coatings was prospected as well.

Lithium metal anode is considered to be the most promising anode candidate for the next generation of highspecific-energy battery chemistry due to its extremely high theoretical specific capacity and the lowest redox potential. However, the employment of lithium metal anode has been plagued by the inevitable dendrite formation and the infinite volume change. This leads to the low coulomb efficiency and poor cycle stability of the corresponding lithium metal batteries. In this mini-review, for the first time we comprehensively explained the formation mechanism of lithium dendrites. After a brief discussion, we summarized a typical strategies for designing highly stable lithium metal anodes, including the design of a stable solid electrolyte interface (SEI) layer by regulating the electrolyte components and the construction of stable three-dimensional collectors. Based on summarizing the crucial literature, we further analyzed the drawbacks and challenges in the present review and put forth a prospect for further development of highly stable lithium metal anodes for practical Li metal batteries.

以人工合成镁钙砂、电熔镁砂为主原料,无水酚醛树脂作为结合剂,制备了不烧镁钙系试样.研究了二茂铁外加量(质量分数分别为0、0.5％、1％、1.5％)对试样性能的影响,并通过SEM和XRD分析了试样的显微结构和相组成.结果表明:1)经过200、1650℃热处理后,试样的体积密度、常温耐压强度和抗水化时长随着二茂铁含量的增加呈先上升后下降的趋势,当二茂铁含量为1％(w)时,性能最佳;2)1650℃热处理后,二茂铁的引入可以在试样中形成铁酸钙,且有部分碳残留.

以人工合成镁钙砂和电熔镁砂为主要原料,无水酚醛树脂为结合剂,二茂铁为催化剂,制备不烧镁钙系耐火材料.探究在还原气氛下二茂铁对不烧镁钙系耐火材料性能的影响,并利用SEM和XRD对试样的显微结构进行观察分析.结果表明:(1)二茂铁的加入使得不烧镁钙系耐火材料的常温力学性能、抗水化性能及高温性能等均有所提高,其抗水化性能及抗渣性能显著提高,荷重软化温度提高和压蠕变性能的改善增强了实际应用能力;(2)通过观察加入1％二茂铁的不烧镁钙系耐火材料的微观组织结构,发现催化无水酚醛树脂形成原位合成网架结构,且铁、碳元素主要分布在有机网架结构内,可以改善性能;(3)还原气氛下1 200℃热处理后,二茂铁的加入仍会对试样的体积密度、显气孔率和常温耐压强度起到改善作用,试样的原位合成有机网架结构和铁、碳元素的颗粒分布即使在高温下仍有所保留,并没有完全破坏.

利用发泡法在1400℃下烧成并保温4 h,制备超轻硅质耐火材料.探究水的加入量、废硅砖粉加入量及搅拌时间对试样的气孔率、体积密度、常温耐压强度及热导率的影响.结果表明:随着水加入量的增加,试样的气孔率增加而体积密度、常温耐压强度、热导率则降低,加入量为50％时性能较好,当加入过多时会对试样的结构产生不利影响;随着废硅砖粉加入量的增大,试样的气孔率增加,体积密度、常温耐压强度与热导率减小,当加入量为30％时,试样的气孔率最高,体积密度、常温耐压强度与热导率最低;随着搅拌时间的增加,试样体积密度减小,气孔率增大,当搅拌时间为15 min时,试样的体积密度最低,气孔率最大,常温耐压强度最高,热导率最低,气孔数量多,孔径均一且在试样中分布均匀.

由于纳米碳材料具有优异的力学性能、稳定的化学性能和热稳定性,因此纳米碳材料迅速成为广大研究者的研究热点并在诸多领域显示出广阔的应用前景.目前,纳米碳材料在耐火材料中的应用已取得了诸多的科研成果.文中总结了利用纳米碳材料改善耐火材料力学性能的研究成果,介绍了在耐火材料中引入纳米碳材料的方法,比如直接添加法和原位生长法.对比了不同引入纳米碳材料方法的优缺点.并对纳米碳材料在耐火材料行业的应用前景与发展趋势进行了展望.