The Preparation Of SiC By Precursor Infiltration Pyrolysis And The Influence Of SiC On The Improperty Of C-Materials

The fabrication of SiC fiber,coating and composites from PCS precurcor has the advantages of low treating temperature,varing insititute and construction,high purity and high performernace. The SiC coating was made on the surface of 3-D carbon fiber perform by PIP,and the 3-D carbon fiber preform/SiC/Al₂O₃ composites were further manufactured by sol impregnation in situ decomposition processing.The uniform SiC coating on the surface of 3-D carbon fiber preform were prepared by PIP,and the coating improved the oxidation-resistance of the 3-D carbon fiber preform. Result shows that the 3-D carbon fiber preform treated by 15% PCS for 3-turn behaving the best oixdation-resistance.The oxidation kinetics and mechanism of SiC coating / carbon fiber preorm was studied by non-isothermal TGA and DTA. The results show that the oxidation process of material in non-isothermal condition exhibits self-catalytic,the oxidation mechanism is 1-dimensional diffusion,the kinetic parameters are lg A = 10.12 min^-1 and Ea = 224.96 kJ·mol^-1.The isothermal mechanisam at low temperature is included by diffusion and oxide reaction, and high temperature oxide reaction only.The sol AlCl₃ as impregnant was used to make 3-D carbon fiber preform/SiC/Al₂O₃. The interfacial bonding properties between fiber and ceramic can be improved by gradient coating.