Preparation of SiC ceramic by reactive melt infiltration and their impact resistance

Sun Mengyong, Qu Junfeng, Li Guobin, Wang Wenlong, Sun Shuli, Feng Ying

2026, (2): 93-97. doi：10.3969/j.issn.1001-1935.2026.02.001

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To reveal the dynamic damage mechanism of SiC ceramics,a SiC ceramic was fabricated via reactive melt infiltration using SiC powder,B₄C powder and carbon powder as starting materials,and Si powder as the infiltrant.The phase composition,microstructure and impact resistance of the as-prepared ceramic were mainly investigated,and the dynamic mechanical behavior was analyzed.The results show that the SiC ceramic contains SiC,B₁₂(C,Si,B)₃ and Si;and the residual silicon content is 14.3%-15% by volume.The ceramic exhibits flexural strength of 340 MPa,fracture toughness of 4.6 MPa·m^1/2,and Vickers hardness of 20.5 GPa.The ceramic presents an obvious single-peak strain rate strengthening effect;when the true stress reaches 1 950 MPa,cracks propagate preferentially along the impact loading direction,and the material undergoes avalanche crushing after damage accumulates to a critical point.

Preparation and properties of CA₆-MA composite materials

Liu Xingyan, Chen Ping’an, Qiao Mengke, Chen Fu, Wu Jiang, Li Xiangcheng

2026, (2): 98-102. doi：10.3969/j.issn.1001-1935.2026.02.002

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To solve the bottleneck problems of high sintering temperature and low mechanical strength of calcium hexaluminate (CA₆)-magnesium aluminate spinel (MA) composite materials,CA₆ powder,MA spinel powder and ρ-Al₂O₃ powder were used as raw materials to prepare CA₆-MA composite materials by heat treating at 1 600 ℃ for 5 h.The effects of the MA powder addition (the total mass fraction of CA₆ powder+MA powder was fixed at 100%,and the mass fractions of MA powder were 10%,30%,50% and 100%,respectively) and ρ-Al₂O₃ addition (10%,50%,70%,100%,150% and 200% of the total mass of CA₆ powder+MA powder) on the microstructure and properties of the materials were investigated.The results show that:(1)increasing the MA powder addition is beneficial to improving the densification of materials;(2)increasing the ρ-Al₂O₃ powder addition can improve the density and strength of the materials;when the MA powder addition is 50% and the ρ-Al₂O₃ powder addition is 150%,the sample exhibits the optimal comprehensive properties,with bulk density of 2.80 g·cm^-3,apparent porosity of 26.7%,linear shrinkage of 18.4%,cold modulus of rupture of 72.5 MPa,and cold compressive strength of 510 MPa.

Effect of α-Al₂O₃ micropowder addition on structure and properties of magnesia-based crucible materials

Zhang Wenke, Li Suping, Jin Yi, He Siyao, Ma Chengliang, Liu Xinhong, Feng Runtang, Tian Xiaoli, Liu Bai-kuan

2026, (2): 103-107. doi：10.3969/j.issn.1001-1935.2026.02.003

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To improve the properties of magnesia-based crucible materials,fused magnesia and α-Al₂O₃ micropowder were used as main raw materials,and magnesium chloride hexahydrate as the binder to prepare magnesia-based crucible materials.The effects of the α-Al₂O₃ micropowder addition (0,2%,3%,5% and 7%,by mass) on the phase composition,cold physical properties,hot modulus of rupture,thermal shock resistance and microstructure of the materials were investigated.The results show that the addition of a small amount of α-Al₂O₃ micropowder forms a limited substitutional solid solution with magnesia,causing lattice distortion,improving the bonding between particles and promoting the sintering of the samples;after reaching the solid solution limit,alumina reacts with magnesia to form magnesium aluminate spinel in-situ,accompanied by volume expansion.When the α-Al₂O₃ micropowder addition is 2%,the sintering-promoting effect is stronger than the expansion effect caused by the spinel formation,so the sample exhibits the maximum cold modulus of rupture,cold compressive strength and hot modulus of rupture at 1 400 ℃,which are 24.9,85.1 and 2.3 MPa,respectively.The cold modulus of rupture after 1 and 3 cycles of thermal shock by air quenching is also the highest,reaching 12.4 and 8.3 MPa,respectively.

Preparation and properties of dense periclase-forsterite composite aggregates

Yuan Xiaozhou, Cao Ruiqi, Ma Beiyue, Lyu Caiwen, Yang Xin

2026, (2): 108-112. doi：10.3969/j.issn.1001-1935.2026.02.004

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To develop a new type of refractory aggregates for tundish lining refractory castables and alleviate the environmental,social,and economic pressures caused by industrial solid waste materials,periclase-forsterite composite aggregates were prepared via the high-temperature solid-state sintering method using fused magnesia powder and silicon cutting waste as the main raw materials and liquid phenolic resin as the binder.The effect of the calcination temperature (1 400,1 500,and 1 600 ℃) on the properties of the samples was investigated.The results show that:(1)with the increasing calcination temperature,the peak intensity of both MgO and Mg₂SiO₄ in the samples increases;the forsterite grains grow continuously and form tight interfacial bonding with periclase grains;the microstructure evolution effectively promotes the overall uniform densification of the samples;meanwhile,the apparent porosity of the samples gradually decreases,the bulk density gradually increases,and the linear shrinkage,volume shrinkage rate,and cold compressive strength all show an upward trend;(2) when the calcination temperature is 1 600 ℃,the samples exhibit the optimal comprehensive properties,with apparent porosity of 3.3%,bulk density of 3.02 g·cm^-3,linear shrinkage of 9.7%,volume shrinkage of 23.0%,cold compressive strength of 178 MPa,and compressive strength retention ratio after thermal shock of 115%.

Influence of low-silica fused magnesia waste on properties of magnesia-based castables

Yang Xin, Cao Rui-qi, Ma Beiyue, Yuan Xiaozhou, Yang Huan

2026, (2): 113-117. doi：10.3969/j.issn.1001-1935.2026.02.005

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To improve the utilization of low silica fused magnesia waste,magnesia based castables were prepared using fused magnesia,sintered magnesia and low silica fused magnesia waste as main raw materials,replacing sintered magnesia by low silica fused magnesia waste of equivalent particle size (≤75 μm).The effects of the substitution amounts of low silica fused magnesia waste (0,5%,10% and 15%,by mass) on the physical properties and thermal shock resistance of magnesia based castables were investigated.In combination of the microstructure and phase composition,their influence mechanism on the castable properties was analyzed.The results show that:(1)after the heat treatment at 1 550 ℃,with the increasing substitution of low silica fused magnesia waste,the linear shrinkage rate of the castables decreases gradually,the bulk density increases significantly,the apparent porosity shows an obvious downward trend,and the cold compressive strength and strength retention ratio after thermal shock test both increase first and then decrease;(2)when the substitution of low-silica fused magnesia waste is 10%,the magnesia based castables exhibit the optimal comprehensive properties.

Influence of high-carbon ferrochromium slag addition on structure and properties of high-alumina wear-resistant castables

Zhang Jun, Yu Haili, Zhang Sanhua, Cao Zhuang, Zhou Huijun, Zhang Zhihua

2026, (2): 118-123. doi：10.3969/j.issn.1001-1935.2026.02.006

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In order to explore the application feasibility of high-carbon ferrochromium slag as a refractory raw material in high-alumina wear-resistant castables,high-carbon ferrochromium slag,high-alumina bauxite,activated alumina micropowder,silica micropowder and pure calcium aluminate cement were used as main raw materials to prepare high-alumina wear-resistant castables.The effects of the high-carbon ferrochromium slag addition (0,20%,40%,60%,and 80%,by mass) on the structure and properties of the castables heat treated at different temperatures (110,800,1 000,and 1 200 ℃) were studied.The results show that with the increasing high-carbon ferrochromium slag addition,the bonding between aggregates and matrix is getting tight,and the sintering is improved.The bulk density and hot modulus of rupture of the specimens increase gradually;the cold modulus of rupture and cold compressive strength first decrease and then increase.The wear loss of the samples heat treated at 800 ℃ decreases gradually,so the wear resistance improves gradually.

Preparation of Al-Si alloy phase change thermal storage composite ceramics by selective laser sintering and their strengthening and toughening mechanism

Li Yinfei, Zhang Meijie, Gu Huazhi, Chen Ling, Yang Shuang, Huang Ao, Yin Yucheng

2026, (2): 124-130. doi：10.3969/j.issn.1001-1935.2026.02.007

Abstract ( ) PDF (2709KB)( )

Metal-based high-temperature phase change thermal storage composite materials exhibit high heat storage density and high thermal conductivity,and thus can be applied to long-term energy storage and high-temperature thermal management.To fully exploit the advantages of metals in high-temperature phase change thermal storage and improve the comprehensive properties of phase change thermal storage composite ceramics,AlSi10Mg@Al₂O₃ microcapsule powder was prepared via pressurized steam treatment and heat treatment at 1 000 ℃ for 3 h using AlSi10Mg powder (15-53 μm) as the raw material.Then,with AlSi10Mg as the binder (the additions were 5%,8%,11% and 14%,by mass),the green bodies of high-temperature phase change thermal storage composite ceramics were fabricated by the selective laser sintering (SLS) method.After that,whiskers,fibers and other reinforcing phases were formed between Al-Si@Al₂O₃ particles via heat treatment at 1 000 ℃ for 3 h in N₂ atmosphere,so as to enhance the mechanical and thermal properties of the composite ceramics.The results show that:the formation of AlN in the composite ceramics exerts a significant effect on the properties;with the increase of the AlSi10Mg binder addition,the AlN formation in the composite ceramics first increases and then decreases.When the binder addition is 11%,it is conducive to the formation of more AlN,and the composite material achieves the optimal comprehensive performance.Its flexural strength reaches 76.0 MPa,the thermal conductivity at room temperature is 54.2 W·(m·K)^-1,the latent heat values of endothermic and exothermic processes are 296.85 and 295.05 J·g^-1 respectively,and the latent heat retention ratio relative to the original microcapsules reaches 89.1%.After 100 thermal cycles,the mass loss rate is only 0.197%,and the latent heat retention ratios of the endothermic and exothermic processes reach 98.5% and 91.1%,respectively.

Effect of desilicated zirconia on properties of MgO-MgAl₂O₄ refractories

Zhang Junjie, Yu Renhong, Qian Jing, Zang Yunfei, Li Mancang, Zheng Shihao, Yang Minghui

2026, (2): 131-135. doi：10.3969/j.issn.1001-1935.2026.02.008

Abstract ( ) PDF (1815KB)( )

In order to improve the service life of MgO-MgAl₂O₄ refractories for RH refining,MgO-MgAl₂O₄ refractories were prepared using the sintered magnesia,fused magnesia,fused magnesium aluminate spinel,sintered magnesium aluminate spinel and desilicated zirconia as raw materials,and the calcium lignosulfonate solution as the binder,pressing,drying at 120 ℃ for 72 h,and heat-treating at 1 600 or 1 700 ℃ for 6 h.The effects of desilicated zirconia additions (0,2%,and 4%,by mass) on the phase composition,microstructure and properties of the MgO-MgAl₂O₄ refractories were mainly investigated.The results show that:(1)desilicated zirconia promotes the in-situ formation of CaZrO₃ and (Mg,Zr)(Al,Zr)₂O₄ solid solution in the material.The former hinders the further penetration of molten slag,while the latter enhances the corrosion resistance of MgAl₂O₄ to FeO;(2)with the desilicated zirconia addition increasing from 0 to 4%,the apparent porosity of the material decreases,the bulk density increases and the thermal shock resistance improves.Moreover,with the increase of the heat treatment temperature,the diffusion of Zr element accelerates and the CaZrO₃ formation amount increases;(3)after adding 4% desilicated zirconia and heat-treating at 1 700 ℃,the comprehensive performance of the material is the best,the apparent porosity is 12.2%,the bulk density is 3.14 g·cm^-3,the cold crushing strength is 128 MPa,the thermal shock resistance (1 100 ℃,water quenching) is 12 cycles,and the refractoriness under load is above 1 700 ℃.

Effect of Fe₂O₃ on performance of magnesia water-based gunning mix for converter large area

Xiao Yangwu, Ma Xiaoyi, Xiong Jiquan, Zhang Xiaocun, Nie Jianhua, Liang Yonghe, Ju Maoqi, Sun Huidong

2026, (2): 136-140. doi：10.3969/j.issn.1001-1935.2026.02.009

Abstract ( ) PDF (1569KB)( )

To improve the performance of water-based gunning mix for converter large area and prolong the service life of converters,magnesia water-based gunning mix was prepared with fused magnesia and silica fume as main raw materials.The effects of the sintering aid Fe₂O₃ additions (0,1%,2%,and 3%,by mass) on the properties of the gunning mix were studied,and its action mechanism in the gunning mix was explored.The results show that:(1)the introduction of Fe₂O₃ into the water-based gunning mix promotes the formation of MgFe₂O₄,which has a similar structure to MgAl₂O₄;and a continuous Mg(Fe,Al)₂O₄ solid solution forms between them,inducing lattice distortion,accelerating ion diffusion rate during the reaction,and promoting sample sintering;(2)Fe₂O₃ reacts with SiO₂ in the sample to form FeO-SiO₂,which is present as a liquid phase at 1 500 ℃,improving the sintering process,strengthening the bonding between particles and matrix,and promoting sample densification;(3)owing to the improved sintering performance,the cold physical properties of the samples are improved and the sintering time is shortened;however,excessive Fe₂O₃ leads to a large linear expansion rate of the sample,resulting in a loose structure.Therefore,the optimal addition of Fe₂O₃ is 2%.

Effect of in-situ synthesized cordierite on cordierite-mullite based saggers

Zhu Zishuo, Wang Yilong, Su Yu-ming, Yang Liandi, Liu Qinghua, Qing Da, Wang Jian, Wu Feng, Han Lu

2026, (2): 141-145. doi：10.3969/j.issn.1001-1935.2026.02.010

Abstract ( ) PDF (1911KB)( )

To improve the performance of cordierite-mullite-based saggers,cordierite-mullite saggers were fabricated via in-situ reaction at 1 345 ℃ for 4 h using cordierite,mullite M60,and tabular corundum as the primary raw materials,and introducing talc powder,Guangxi white clay,and reactive alumina.The effects of talc powder additions (0,2%,4%,6%,8%,and 10%,by mass) on the mechanical properties and corrosion resistance of the saggers were systematically investigated.The results indicate that with the increasing talc powder addition,the bulk density of the samples improves,the apparent porosity decreases,the cold modulus of rupture improves.When the talc powder addition reaches 10%,the sagger exhibits the optimal overall performance,with apparent porosity of 26.0%,bulk density of 2.18 g·cm^-3,cold modulus of rupture of 20.6 MPa,and favorable thermal shock resistance.Compared to the talc-free sample,the mechanical properties are significantly improved,and the sagger demonstrates excellent corrosion resistance to high-nickel ternary cathode precursors.

Effect of borax on melting and crystallization properties of high-titanium fluorine-free mold fluxes

Li Tao, Zhang Yulu, Zhang Di, He Zhisen, Wang Wei, Liu Lei

2026, (2): 146-150. doi：10.3969/j.issn.1001-1935.2026.02.011

Abstract ( ) PDF (1072KB)( )

Titanium-containing fluorine-free mold fluxes show great advantages in environmental protection and melting performance optimization.However,excessively high titanium content tends to generate high-melting-point substances,which deteriorates the crystallization properties of mold fluxes,and adding borax can remedy the defects of such mold fluxes.High-titanium fluorine-free mold fluxes were prepared using high-titanium blast furnace slag,limestone,quartz sand,soda ash and witherite as raw materials.The influence of flux borax additions (4%,6%,8%,10%,and 12%,by mass) on the performance of the high-titanium fluorine-free mold fluxes was studied,such as the melting temperature,viscosity,crystallization temperature,critical crystallization cooling rate and crystallization incubation time.The results show that with the increase of the borax addition,all the melting temperature indexes of the high-titanium fluorine-free mold fluxes decrease nonlinearly;the viscosity decreases to a low level and then tends to be stable;both the maximum crystallization cooling rate and initial crystallization temperature first increase and then decrease.When the borax addition is 8%,the melting and crystallization properties of the high-titanium fluorine-free mold fluxes are synergistically improved.

3D printing preparation of lightweight thermal insulation alumina refractories based on rheological optimization

Zhang Chun, Wu Bin

2026, (2): 151-155. doi：10.3969/j.issn.1001-1935.2026.02.012

Abstract ( ) PDF (1353KB)( )

To synergistically optimize the comprehensive performance of lightweight thermal insulation alumina refractories and enable their 3D printing,with activated alumina as the raw material and polycarboxylate FS20 as the dispersant,the rheological properties of the slurry were optimized by adjusting the solid loadings (50%,55%,60%,and 65%,by mass),as well as the extra additions (by mass) of binder sodium carboxymethylcellulose (CMC,0.2%,0.4%,0.6%,and 0.8%),plasticizer bentonite (1%,2%,3%,4%,and 5%),and pore-forming agent modified rice husk (5%,10%,15%,and 20%).Lightweight thermal insulation alumina refractories were prepared via direct ink writing 3D printing.The results show that the slurry with 60% solid loading has the best rheological properties,with the additions of 0.2% polycarboxylate FS20,0.8% CMC,4% bentonite,and 15% modified rice husk.The lightweight thermal insulation refractory material was successfully prepared by 3D printing,with a bulk density of 2.16 g·cm^-3,an apparent porosity of 33.4%,a cold modulus of rupture of 46.2 MPa,and a thermal conductivity of 0.47 W·(m·K)^-1.

Effect of fluxes on properties of gangue-based foamed ceramics

Zhang Xiangfei, Lou Guanghui, Zhang Meng-zhen, Li Jing, Zhang Wanyu, Zhang Yisheng, Sun Maoze

2026, (2): 156-160. doi：10.3969/j.issn.1001-1935.2026.02.013

Abstract ( ) PDF (1519KB)( )

To realize the resource utilization of solid waste gangue and develop high-performance foamed ceramics,gangue-based foamed ceramics were prepared using gangue as the primary raw material and SiC as the foaming agent,with Na₂B₄O₇,Na₂CO₃,H₃BO₃ and Na₂SiO₃·9H₂O as the fluxes,respectively,heat treating at 1 180 ℃ for 30 min.Firstly,the effect of flux types on the properties of the foamed ceramics was investigated,and Na₂CO₃ was identified as the optimal flux.Subsequently,the influence of the Na₂CO₃ additions (0,5%,10%,15%,and 20%,by mass) on the properties of the ceramics was further studied.The results indicate that the introduction of fluxes enables the preparation of gangue-based foamed ceramics at a low heat treatment temperature of 1 180 ℃.The foamed ceramic with 15% Na₂CO₃ exhibits the best overall properties:bulk density of 0.29 g·cm^-3,compressive strength of 6.12 MPa,and apparent porosity of 84.3%.

Design and fabrication of metamaterial absorber based on reactance compensation

Tan Yuyao, Gao Xinghao, Qiao Mengke, Li Xiangcheng

2026, (2): 161-166. doi：10.3969/j.issn.1001-1935.2026.02.014

Abstract ( ) PDF (1393KB)( )

Strong electromagnetic fields can be generated during the operation of induction furnaces and microwave heating devices.Among them,C-band electromagnetic waves(4-8 GHz) can effectively penetrate into some lining materials and induce eddy currents or dielectric heating inside,leading to local overheating or structural damage of the materials.Therefore,developing materials with high-temperature microwave absorption performance in the C-band is of significant importance for enhancing equipment safety and prolonging the service life of furnace linings.The electromagnetic response characteristics of a frequency selective surface (FSS) were analyzed through equivalent circuit modeling.Based on reactance compensation,an octagonal star-square loop FSS structured metamaterial absorber was designed,and its wave absorption performance and loss mechanism were investigated.The analysis reveals that the metamaterial absorber achieves effective impedance matching through reactance compensation.Under the combined effect of the resonant loss and ohmic loss,the effective absorption band with reflection loss below -10 dB covers the entire C-band,and the absorptivity at 4.8 GHz exceeds 0.99.Meanwhile,the structure exhibits favorable stability against oblique incidence from 0° to 90°.The experimental results indicate that the reflection loss of this metamaterial absorber is more than 90%.The designed FSS metamaterial absorber has high application potential in reducing electromagnetic interference and prolonging the service life of furnace bodies.

Progress in chemical impurity removal technologies for magnesite and its tailings

Lan Zhipeng, Yuan Xiao-zhou, Yang Xin, Yang Huan, Wang Qianqian, Zhao Guangyi, Li Guangming, Ma Beiyue

2026, (2): 167-172. doi：10.3969/j.issn.1001-1935.2026.02.015

Abstract ( ) PDF (939KB)( )

It is difficult for physical mineral processing to treat magnesite with fine dissemination and isomorphic impurities,resulting in resource waste.Therefore,the present situation of chemical impurity removal technologies for magnesite and its tailings was summarized,including the widely used ammonium salt method and acid leaching method,the carbonization method based on specific reactions,the simple and environmentally friendly hydration method,and the chlorination roasting method with high purification efficiency.It was pointed out that the impurity removal of low grade magnesite should focus on the research and development of technologies and green leaching agents as well as the construction of a full industrial chain model.

Research progress on strengthening and toughening of high-alumina high-voltage electric porcelain materials

Yue Yonggang, Tian Xiaoyun, Dang Dawei, Li Zhihui, Jing Nan, Chong Xiaochuan, Ding Donghai, Xiao Guo-qing

2026, (2): 173-178. doi：10.3969/j.issn.1001-1935.2026.02.016

Abstract ( ) PDF (946KB)( )

Nowadays,high-alumina electric porcelain has become a core component to ensure the safe operation of the power grids.Due to its brittleness and high sensitivity to defects,traditional electric porcelain struggles to meet the reliability requirements for extreme environments,therefore,the research and development of high-strength and high-toughness high-voltage electric porcelain has become the key to ensuring the long-term stable operation of the power grids.Three effective methods for enhancing the performance of high-alumina high-voltage electric porcelain materials and their mechanisms were summarized:the optimization of the preparation process improves the mechanical properties and reliability through improving the densification and uniformity of the materials;the optimization of raw material selection,which adjusts the ratio and improves the purity,enhances the mechanical strength and electrical insulation;and additive toughening technology,especially whisker toughening and nanoparticle dispersion toughening,significantly improves the fracture toughness and resistance to crack propagation.

Research progress on 3D printing technology for alumina ceramics

Yan Xiuxiu, Wang Yong, Cao Jiwei

2026, (2): 179-184. doi：10.3969/j.issn.1001-1935.2026.02.017

Abstract ( ) PDF (941KB)( )

Alumina ceramics demonstrate significant application value across numerous fields due to their exceptional properties,such as high hardness,wear resistance,high-temperature resistance,chemical stability,electrical insulation,and biological inertness.This paper focused on the current research status of the binder jetting 3D printing technology,vat photopolymerization technology,selective laser sintering/melting technology,and fused deposition modeling technology in the fabrication of alumina ceramics.The advantages and disadvantages of each process were compared and analyzed.Finally,the development of 3D-printed alumina ceramics was prospected.

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