关键词: 堇青石质隔热材料, 莫来石晶须, 硅酸铝陶瓷纤维, 热导率, 多级结构

Abstract: Aiming at improving the low strength of cordierite insulation materials used in high-temperature industry,cordierite insulation materials were prepared using kyanite,clay,magnesia powder as raw materials,starch as the pore forming agent and curing agent,adding a suitable amount of aluminum silicate ceramic fiber and MoO₃.The prepared materials have a mullite whisker-ceramic fiber multi and interlocked structure by the in-situ formation of mullite whiskers on the surface of aluminum silicate fiber catalyzed by MoO₃.The effects of aluminum silicate ceramic fiber under the action of MoO₃ heat treated at different temperatures (1 200,1 250,1 300 and 1 350 ℃) on the microstructure,cold mechanical properties and thermal conductivity of the materials were studied.The results show that:under the action of MoO₃,mullite whiskers grow on the surface of aluminum silicate fiber,showing a vertical trend basically,and partially inserting in well-developed cordierite grains;with the heat treatment temperature increasing,the mullite whiskers on the surface of aluminum silicate ceramic fiber changes from short rods to slender needles,and the length to diameter ratio increases gradually;the cordierite material with the fiber-whisker multi and interlocked structure has improved mechanical properties while reduced thermal conductivity;the specimen heat treated at 1 350 ℃ has the optimal performance.

Key words: cordierite insulation materials, mullite whisker, aluminum silicate fiber, thermal conductivity, multi-structure