The preparation of silicon carbide-based multiphase ceramics using silicone polymers as precursors is a new method developed in recent years. Ceramic precursors can be easily mixed with the first phase because of their meltable and soluble properties. Ceramic precursors can complete inorganic transformation at relatively low temperatures, which can reduce sintering temperature during the preparation of ceramic materials.
This method has many unique characteristics, such as simple process, less equipment and low cost. However, the shrinkage and porosity of the ceramic precursor increase due to the change of the gas small molecule pyrolysis products and the increase of the density during the pyrolysis process. In order to solve this problem, active fillers can be added to ceramic precursors. When the precursor containing active filler is cracked, on the one hand, the active filler reacts with gaseous small molecule pyrolysis products and active atmosphere (NZ, etc.) to control the porosity and shrinkage of ceramic products. At the same time, the reactive product of active filler reacts with the matrix to form multiphase ceramics, which can improve the performance of matrix ceramics.
The chemical reaction of active filler T powder in the pyrolysis of polysiloxane and the microstructure of multiphase ceramics were studied. In this study, Polycarbosilane was used as the precursor. The chemical reactions, product structure and the effects of active filler CrSi2 powder on the porosity, shrinkage and strength of Polycarbosilane were studied.