Aqueous tape casting process for SiC

Abstract

The condition for the preparation of stable SiC slurries by aqueous tape casting was identified. To acquire stable uniform slurries, the influences of dispersant, solid loading, sintering additives, binder and plasticizer on the rheological properties and viscosity were investigated. The conditions for preparing stable SiC slurries were studied and optimized. After tape casting and drying, the green SiC sheets showed smooth surface and homogeneous microstructure. The SiC ceramic can be densified to 98.89% after hot-pressing at 1850 °C (at 25 MPa in Ar for 30 min). The flexural strength, hardness, and toughness are 779.5 ± 39.2 MPa, 21.51 ± 0.70 GPa and 5.54 ± 0.26 MPa m 1/2, respectively. SEM shows a fine microstructure with few pores in the sintered samples. The fracture surface exhibited predominantly intergranular fracture type.