Effect of RE_2(CO_3)_3 on Properties of Mullite/SiC Based Foam Ceramics Filter

Mullite-moissanite composites foam ceramics filters(FCF) with high porosity,light weight with highly flexlble strength and higher thermal were fabricated from an aqueous slurry.The process is that aceramic slurry with high viscosity and thixotropic behavior was prepared with SiC,kaolin clay,alumina and other additives powder as major materials;and the RE2(CO3)3 is sintering aid.The influences of RE2(CO3)3 content on the sintering temperatures,thermal shock,the bulk density on the solution and the phase compositions were discussed.The main crystal phase of mullite-moissanite composites without RE2(CO3)3 are mullite,moissanite,and cristobalite.After adding 3 % RE2(CO3)3,the main crystal phase are mullite,cristobalite and SiC.The diffraction peak of cristobalite is lower than mullitemoissanite composites without RE2(CO3)3.Sintering temperature of FCF decreases from 1 450 ℃to 1 400 ℃,and sintering time decreases 2 hours to 0.5 hours and the bulk density raises from 0.59 g/cm3 to 0.65 g/cm3,also thermal shock raises from 5 times to 7 times.