Sol-gel precursor for alumina-silicon carbide Nanocomposite through controlled flocculation And humidity drying

摘要

An alumina-silicon carbide nanocomposite precursor was prepared by a sol-gel method using a boehmite sol and a kinetically stable colloidal suspension of ultrafine (<0.3 μm) silicon carbide particles. Flocculation of the boehmite sol containing uniformly dispersed silicon carbide particles using ammonia, immobilised the dis- persed particles resulting in uniform drying and shrink- age. Drying under controlled humidity conditions of 45 deg.C and 60-70/100 relative humidity, produced crack free green precursor bodies which retained their shape after heat treatment at 1450 deg.C.