Process for manufacturing high density slip-cast fused silica bodies

摘要

Fused silica ceramics plays demanding role in high velocity missile/aircraft'radome development. Slip casting is the most common and commercially viable process utilized for radome production. Unfortunately slip casting cannot afford high density due to its poor green packing density which in turn results in poor rain erosion resistance. Present invention discloses process for preparing high density fused silica bodies by adding boron oxide (B₂O₃) with the commercially available high purity fused silica as sintering aid cum de-vitrification inhibitor. Various concentrations of B₂O₃ were added to high purity fused silica. Thus formed compositions were made into slip-castable slurries in aqueous medium without any addition of dispersing agents. The reheological properties like mild shear thinning and low thixotropic behaviour of the slurries were established. These slurries were then slip-casted in plaster of parries mold. The green and sintered properties of the casted samples were studied. The sintered sample with density higher than 2 g/cc (90-95% of the theoretical density) was achieved without de-vitrification. XRD studies on sintered samples showed the amorphous nature of the sample. The improved properties of fused silica system can favor its utilization in radome applications.