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

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