Opaque silica glass fabricated by slip casting and sintering (Part 1) - Optimization of slip casting and sintering processes

Large bodies of opaque silica glass were fabricated by slip casting and sin tering. The raw material was highly pure synthetic silica powders. The slip was prepared without adding any binder. Three types of powders with differ ent particle sizes were used to examine the influence of particle size on s lip casting. A significant influence was found, and large green compacts co uld be obtained only by using a powder with an average particle size of 5 m u m. Three types of mold materials, plaster, plastic resin and mixtures of both, were tested. The plaster mold fabricated slip casting operation, but caused Ca contamination (about 3 ppm) into the resultant glass. After slip casting, the compacts were sintered at 1800 degrees C in nitrogen atmospher e. According to this process, a large ring (phi 400 mm) of opaque silica gl ass could be fabricated without any appreciable distortion.