Abstract: To improve the oxidation resistance of silicon carbide materials for coke ovens,SiAlON-SiC,Si₂N₂O-SiC and Si₃N₄-SiC refractory samples were prepared by nitridation at 1 420 ℃ for 10 h with silicon carbide particles (2.5-1.43,1.43-0.5 and 0.5-0.088 mm) and fine powder (≤0.088 mm),silicon powder (≤0.088 mm),alumina micropowder (≤0.044 mm) and SiO₂ micropowder (≤1 μm) as raw materials and lignin as the binder.Then the samples were pre-oxidized at 650,850,1 050 and 1 250 ℃ for 5 h,respectively.The effect of pre-oxidation on the oxidation resistance of the nitrided samples was investigated.The results show that:(1)at low temperatures (≤850 ℃),the oxidation resistance of the Si₃N₄-SiC materials is better than that of the SiAlON-SiC and Si₂N₂O-SiC materials,while at 850-1 250 ℃,the oxidation resistance of the SiAlON-SiC materials is the best;(2)after pre-oxidation treatment at 1 250 ℃,the SiAlON-SiC materials show the lowest apparent porosity of 2.4% and the best oxidation resistance,because an oxide layer is formed on the surface of the samples,which can reduce the apparent porosity and improve the oxidation resistance;(3)for the heat exchanger of coke ovens,silicon nitride bonded silicon carbide materials are suitable below 850 ℃ and SiAlON bonded silicon carbide materials are suitable above 850 ℃;for the denitration tube of coke ovens,SiAlON bonded silicon carbide materials are suitable.

Key words: coke ovens, silicon carbide, nitridation sintering, oxidation resistance

摘要： 为改善焦炉用碳化硅材料的抗氧化性,以碳化硅颗粒(2.5～1.43、1.43～0.5、0.5～0.088 mm)及细粉(≤0.088 mm)、单质硅粉(≤0.088 mm)、氧化铝微粉(≤0.044 mm)、SiO₂微粉(≤1 μm)为原料,木质素为结合剂,于1 420 ℃保温10 h氮化烧成SiAlON-SiC、Si₂N₂O-SiC和Si₃N₄-SiC耐火材料试样,再分别经650、850、1 050、1 250 ℃保温5 h预氧化。研究预氧化对氮化后试样抗氧化性的影响。结果表明:1)在较低温度(≤850 ℃)下,Si₃N₄-SiC材料的抗氧化性优于SiAlON-SiC与Si₂N₂O-SiC材料的,在850~1 250 ℃时,SiAlON-SiC材料的抗氧化性最好。2)3种氮化后试样中,经1 250 ℃预氧化后SiAlON-SiC试样的显气孔率最低,为2.4%,抗氧化性最优,因为氧化后试样表面形成了氧化层,可以降低显气孔率从而提高抗氧化性。3)在焦炉换热器方面,850 ℃以下区域选择氮化硅结合碳化硅材料,850 ℃以上区域选择赛隆结合碳化硅材料;在焦炉脱硝管方面,选择赛隆结合碳化硅材料更为合适。

关键词: 焦炉, 碳化硅, 氮化烧结, 抗氧化性