Cylindrical mullite-sheet shape alumina composite powder and preparation method thereof

The invention relates to cylindrical mullite-sheet shape alumina composite powder and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing 60-88wt% of mullite powder and 12-40wt% of aluminium fluoride powder to obtain mixed powder; adding deionized water in the mixed powder according to the mass ratio of (0.01-0.05):1, uniformly mixing the materials, ageing a mixture, and compacting the mixture to obtain a base substrate; then placing the base substrate in an enclosed alumina crucible, insulating the material for 2-16 hours at the condition of 1400-1650 DEG C, and cooling the material to room temperature to obtain the cylindrical mullite-sheet shape alumina composite powder. The Al2O3 content in the mullite powder is greater than or equal to 71.8wt%, and particle size is less than or equal to 80 mm. The AlF3 content in the aluminum fluoride powder is greater than or equal to 98wt%, and particle size is less than or equal to 80 mm. The cylindrical mullite-sheet s