Application of preceramic polymer for shape-forming of multiphase SiC/Si_3N_4 ceramic parts

摘要

The purpose of the present work is to fabricate shape-complex SiC/Si_3N_4 multiphase ceramic parts (such as blade) using preceramic polymer (Polycarbonsilane PCS) as shape-forming binders. SiC/Si_3N_4 multiphase ceramics are formed by in-situ pyrolysis and sintering from PCS/Si_3N_4 green body. Divinylbenzene (DVB) is used as active diluent agent to prepare slurry of PCS/DVB/Si_3N_4 at room temperature, and as cross-linking agent to make solid green body of PCS/DVB/Si_3N_4. It is necessary to control precisely rate of pyrolysis temperature of 250-450 degree under 0.3 degree/min in order to obtain a pyrolysis with body of deformation-freee and crack-ffee. Before sintering, decreasing the carbon-rich content in the pyrolysis body, the density of sintered body can be enhanced.