Simplified Aqueous Gelcasting of Silicon Carbide Ceramics

Abstract

A new ceramic forming process, protein coagulation casting (PCC), has been applied for consolidation of green silicon carbide bodies. The process utilizes aqueous ceramic slurries based on egg white (ovalbumin). The silicon carbide powder was dispersed in an aqueous medium without any pH adjustment or addition of any dispersing agents. The ovalbumin based slurries could be gelled simply by heating without use of any chemical additives and it provided sufficient strength for handling the bodies. An addition of ovalbumin to aqueous silicon carbide slurries enhanced the viscosity and thus limited the solid loading. The ovalbumin containing slurries were thixotropic in nature. With the use of the present process, defect free near-net shaped silicon carbide bodies were prepared.