Mechanical properties and high temperature failure mechanism of carbon fibers reinforced polysilazane-derived SiCN ceramic matrix composites via PIP process
Yuelong Tian, Jidong Hu, Zhihai Feng, Xin Sun, Yuan Li, Yifen Xu
Abstract
Carbon fibers reinforced SiCN ceramic matrix composites (C/SiCN) were prepared by PIP with homemade polysilazanes (PSN-T03). The PSN-T03 had a viscosity of less than 500 mPa·s and favorable good chemical stability at 80 ℃, which made it quite applicable for PIP process. PSN-T03’ curing reactions happened at temperatures ranging from 149℃ to 205℃, and conversion to amorphous SiCN ceramics could be finished at temperatures above 700℃ with a 70+ wt% ceramic yield. Tensile strength of C/SiCN composites were 230 MPa and 350 MPa respectively at room and high temperature (1400℃), and bending strength reached 380 MPa and 530 MPa. SiCN ceramics began to lose weight at 1400℃ due to the carbothermic reduction of the silicon nitride phase under inert atmosphere, which results in collapse of the mechanical properties of C/SiCN composites above 1400℃.