材料期刊网

分别以Al2O3、MgO质量比为2．554、3．644和5．823的镁铝尖晶石粉71MA、78MA和85MA为主要原料，以聚合氯化铝和镁砂为凝胶体系，采用发泡法制备了尖晶石隔热材料，并研究了料浆性能及尖晶石隔热材料的性能和显微结构。结果表明：用上述3种粉制成的料浆71MA的黏度随时间的延长而增大，料浆78MA和85 MA的黏度随时间的延长而减小；随着尖晶石原料中Al2 O3含量的提高，1700℃烧后试样的显气孔率逐渐增大，体积密度、常温耐压强度和常温抗折强度逐渐减小，烧后线收缩率逐渐减小，烧后试样中的气孔形状变得不完整，孔壁结构逐渐疏松；综合考虑料浆性能和烧后试样的性能，富铝适度（Al2 O3质量分数76％～80％）的尖晶石原料较适宜采用本工艺来制备尖晶石隔热材料。

Magnesium aluminate spinel insulating materials were prepared by foaming process using mag-nesium aluminate spinel powders 71MA (mass ratio of Al2O3 MgO=2.554),78MA (mass ratio of Al2O3 MgO=3.644)and 85MA (mass ratio of Al2O3 MgO=5.823)as starting materials,aluminium polychlorid and magnesia as gel system.Properties of the slurries,properties and microstructure of the developed in-sulating materials were researched.The results show that:(1)with stirring time prolonging,the viscosity of 71MA slurry increases,but that of 78MA or 85MA slurry decreases;(2)with Al2O3 content in spinel increas-ing,the apparent porosity of the developed insulating materials after fired at 1 700℃increases gradually,the bulk density,the cold crushing strength and the cold modulus of rupture decrease,the linear shrinkage rate decreases gradually,the pores become imperfect,and the pore walls become loose;(3)taking the properties of slurries and the fired insulating materials into condersiation,the Al2O3-rish spinel with suitable Al2O3 (76 mass%-80 mass%)is appropriate to prepare spinel insulating materials using this process.