| Abstract Scope |
Silicon carbide (SiC) is a material of interest for many applications due to its good mechanical properties, oxidation resistance, and high thermal conductivity. Colloidal processing and pressureless sintering can enable forming of complex shaped, dense SiC parts. Direct ink writing (DIW) is a colloidal processing technique where ceramic suspensions are extruded through a nozzle along a path, building up a part layer-by-layer. Ceramic suspensions appropriate for DIW must exhibit shear thinning behavior for extrusion, have a yield stress to retain their shape after extrusion, and have a high particle loading to reduce drying defects. In this work, highly loaded (>50% by volume) aqueous SiC suspensions are developed using small amounts (<5% by volume) of polyethylenimine and polyvinylpyrrolidone additives. The effect of particle loading and polyvinylpyrrolidone amount on the rheological properties and print quality are determined. Density, microstructure, and mechanical properties of direct ink written, pressurelessly sintered SiC will be presented. |