关键词: 焦炉, 碳化硅, 氮化烧结, 抗氧化性

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