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)、SiO_(2)微粉(≤1μm)为原料,木质素为结合剂,于1420℃保温10 h氮化烧成SiAlON-SiC、Si_(2)N_(2)O-SiC和Si_(3)N_(4)-SiC耐火材料试样,再分别经650、850、1050、1250℃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,Si_(3)N_(4)-SiC材料的抗氧化性优于SiAlON-SiC与Si_(2)N_(2)O-SiC材料的,在850~1250℃时,SiAlON-SiC材料的抗氧化性最好。2)3种氮化后试样中,经1250℃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。
To improve the oxidation resistance of silicon carbide materials for coke ovens,SiAlON-SiC,Si_(2)N_(2)O-SiC and Si_(3)N_(4)-SiC refractory samples were prepared by nitridation at 1420℃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 SiO_(2)micropowder(≤1μm)as raw materials and lignin as the binder.Then the samples were pre-oxidized at 650,850,1050 and 1250℃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 Si_(3)N_(4)-SiC materials is better than that of the SiAlON-SiC and Si_(2)N_(2)O-SiC materials,while at 850-1250℃,the oxidation resistance of the SiAlON-SiC materials is the best;(2)after pre-oxidation treatment at 1250℃,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.
作者
孟红涛
马龙斌
刘鑫
Meng Hongtao;Ma Longbin;Liu Xin(不详;Puyang Refractories Group Co.,Ltd.,Puyang 457100,Henan,China)
出处
《耐火材料》
CAS
北大核心
2024年第3期242-245,250,共5页
Refractories
关键词
焦炉
碳化硅
氮化烧结
抗氧化性
coke ovens
silicon carbide
nitridation sintering
oxidation resistance
