Abstract: The oxidation tests of different SiC refractories including Si₃N₄-SiC bricks,Si₃N₄-Si₂N₂O-SiC bricks from domestic and abroad,SiAlON-SiC bricks,oxides bonded SiC bricks,self-bonded SiC bricks as well as SiC castables were carried out in the steam atmosphere (1 000 ℃,32 kg·m^-3·h^-1) for 100,200,300,400 and 500 h,respectively.The mass,the volume,the bulk density and the apparent porosity before and after oxidation were tested.The XRD and SEM analyses were conducted.The results indicate that:(1)under the steam atmosphere condition (1 000 ℃,32 kg·m^-3·h^-1),along the oxidation time from 0 to 500 h,the volume and the mass of the silicon carbide refractories increase,while the bulk density decreases;in terms of the apparent porosity,oxides bonded SiC bricks and SiC castables present an increasing trend,Si₃N₄-SiC bricks,SiAlON-SiC bricks and self-bonded SiC bricks present an increasing trend first,and then a decreasing trend,and Si₃N₄-Si₂N₂O-SiC bricks present a decreasing trend or a trend of decreasing first and then increasing.(2)As for Si₃N₄-Si₂N₂O-SiC bricks,SNO-1 from domestic and SNO-2 from abroad with basically the same chemical and phase composition,the mass change rate of SNO-2 is less than that of SNO-1 during the 200-500 h oxidation,which indicates that the steam oxidation resistance of SNO-2 is better than that of SNO-1.

Key words: silicon carbide, refractory, steam, oxidation resistance

摘要： 对Si₃N₄-SiC砖、国产Si₃N₄-Si₂N₂O-SiC砖、国外Si₃N₄-Si₂N₂O-SiC砖、SiAlON-SiC砖、氧化物结合SiC砖、自结合SiC砖、SiC浇注料等碳化硅耐火材料在1 000 ℃、32 kg·m^-3·h^-1水蒸气条件下分别保持100、200、300、400和500 h进行氧化试验,检测试样氧化前后的质量、体积、体积密度和显气孔率,并进行XRD和SEM分析。结果表明:1)在1 000 ℃、32 kg·m^-3·h^-1水蒸气条件下,随着氧化时间从0增加至500 h,几种碳化硅耐火材料的体积和质量均呈增大趋势,体积密度呈减小趋势;氧化物结合SiC砖和SiC浇注料的显气孔率呈增大趋势,Si₃N₄-SiC砖、SiAlON-SiC砖和自结合SiC砖的显气孔率呈先减小后增大的变化趋势,Si₃N₄-Si₂N₂O-SiC砖的显气孔率呈减小趋势或呈先减小后增大的变化趋势。2)就化学-物相组成基本上相同的国产Si₃N₄-Si₂N₂O-SiC砖(SNO-1)和国外Si₃N₄-Si₂N₂O-SiC砖(SNO-2)而言,在200~500 h段氧化相同时间后,SNO-2的质量变化率均小于SNO-1的,表明SNO-2的抗高温水蒸气氧化性能优于SNO-1的。

关键词: 碳化硅, 耐火材料, 水蒸气, 抗氧化性