Light-weight insulating corundum-spinel materials were in-situ prepared using α-AI2O3 fines ( ≤74 μm) and α-AI2O3 micropowders (d50 =2 μm) as main starting materials,and 5 mass% p-AI2O3 micropow-ders (d50=5 μrn) as binder,extra-adding 0.3 mass% foaming agent and 2 mass% sodium hexameta-phosphate water reducing agent,and firing at 1 550 ℃ for 3 h. Influences of ≤74 μm fused magnesia additions (0,5% ,10% and 15% in mass) on physical properties,thermal conductivity and microstructure of the specimens were researched. The results show that: (1 )with fused magnesia addition increasing,bulk density of the specimens decreases gradually, strength decreases first and increases finally,the specimens shrink gradually and then expand shown by change in dimensions after heating and change in dimensions on heating at 1 550 ℃ for 3 h,and thermal conductivity at 300-900 ℃ decreases: (2) the round pores distribute uniformly in the as-synthesized light-weight insulating corundum-spinel materials: the increase of fused magnesia addition makes the specimens loose,the amount of micropores increase, but big pores change slightly. Considering the comprehensive performance of the material,the optimal addition of fused magnesia is 15 mass%.%以α-Al2O3细粉(≤74 μm)、α-Al2O3微粉(d50=2μm)为主要原料,加入5％(ω)的p-Al2O3微粉(d50=5 μm)为结合剂,外加0.3％(ω)的发泡剂和2％(ω)的六偏磷酸钠减水剂,在1 550℃3 h煅烧后原位制备了刚玉-尖晶石轻质隔热材料,研究了电熔镁砂加入质量分数(0、5％、10％和15％)对刚玉-尖晶石轻质隔热材料物理性能、热导率及显微结构的影响.结果表明:随着电熔镁砂加入量的增加,试样的体积密度逐渐减小,强度先减小后增大,烧后线变化和重烧线变化(1 550℃3h)由收缩逐渐表现为膨胀,试样在300～ 900℃下的热导率均降低；通过发泡法制得的刚玉-尖晶石轻质隔热材料气孔分布均匀,呈球形,且随着电熔镁砂加入量的增加,试样的结构疏松,微孔数量增加,但其对大孔的影响较小.综合考虑试样的各项性能,认为电熔镁砂适合的加入质量分数为15％.
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