Abstract: In order to improve the service life of nitriding furnaces,alumina bubble insulating products with a bonding phase β-SiAlON content of about 30 mass% were prepared by nitridation reaction firing at 1 450 ℃ for 10 h with alumina bubbles,Si powder,Al powder,and Al₂O₃ fine powder and micropowder as main raw materials.The physical properties and chemical composition were tested,and the phase composition and microstructure were analyzed.The analysis shows that β-SiAlON in the β-SiAlON bonded alumina bubble material is mainly slender fibrous crystals.The hot modulus of rupture at 1 350 ℃ of the material is significantly higher than its clod modulus of rupture.The refractoriness under load is high,and the thermal shock resistance is excellent.A 5 m³ batch electric heating nitriding furnace with the material as the working lining has the service life more than 2.5 year,which can be used for more than 130 heats,significantly higher than 100 heats of mullite bonded alumina bubble products.

Key words: alumina bubble insulating product, β-SiAlON, mullite, nitriding furnace, modulus of rupture

摘要： 为提高氮化炉的使用寿命,以氧化铝空心球、Si粉、Al粉、Al₂O₃细粉和微粉等为主要原料,经1 450 ℃保温10 h氮化反应制备了结合相β-SiAlON含量约30%(w)的氧化铝空心球隔热制品,测试了理化性能,分析了物相组成和显微结构。分析表明,β-SiAlON结合氧化铝空心球材料中的β-SiAlON主要为细长的纤维状晶体,1 350 ℃时的高温抗折强度显著高于常温抗折强度,荷重软化温度高,抗热震性优良。将该材料用于5 m³间歇式电加热氮化炉工作衬,使用寿命超过2.5 a,使用炉次超过130炉,明显高于莫来石结合氧化铝空心球制品的100炉。

关键词: 氧化铝空心球隔热制品, β-SiAlON, 莫来石, 氮化炉, 抗折强度