Effects of Viscosity and Pressure on Microstructure and Properties of C sub(f)/SiC-ZrB sub(2) Composites by PIP Process

In this paper, using PCS and ZrB sub(2) precursor as raw materials, we prepared C sub(f)/SiC-ZrB sub(2) composites by precursor infiltration and pyrolysis (PIP) process. We studied the solution of different solid content on the influence of porosity and weight gain,and also studied the effect of pressure and other conditions in the process of infiltration. The viscosity of the solution is tested with NDJ-8S digital rotational viscometer. We observed the microstructure of materials through the scanning electron microscope (SEM). The optimum technological parameter was determined by the experiment. The results showed that: a reasonable solution group in relation to the viscosity of the mixed solution,that is the main factor affecting on the performance of the impregnation; The method of vacuum and pressure impregnation can reduce the preparation period and improve material density rapidly. Under the experimental conditions, the best viscosity of the mixed solution is 54.8 mpa[middot]s, the time of vacuum impregnation is 1.5h, and the optimum value of pressure impregnation is 7 MPa.