Oxidation Mechanism And Oxidation Kinetics Modelling Of 3D C/SiC Composites

Carbon fiber reinforced silicon carbide composite (C/SiC) is one of the most promising thermal-structure materials up to 1650 for aero engines. It is very significant to deeply understand the oxidation mechanisms and establish the oxidation kinetic models for the design and application of C/SiC composites.The oxidation mechanisms of 3D C/SiC composites in air, in water vapor and in oxygen/water vapor coupling environment have been clarified on the basis of oxidation behaviors and microstructure analysis of C/SiC composites. The oxidation kinetics models of the composites in oxygen and in oxygen/water vapor have been established respectively based on the theories of chemical reaction kinetics and mass transport. The software platform of factorization for analysis of C/SiC composites oxidation behaviors has been developed. The main contents of this work are as follows:1. The analyses of the microstructures as well as the characterizations of microcracks, deposition defects and residual pores of 3D C/SiC composites have been done to determine the main diffusion channels of oxygen into the composites at different temperature domains.2. The oxidation mechanisms of 3D C/SiC composites in air, in water vapor and in oxygen/water vapor coupling environment have been systemically analyzed based on the research of oxidation behaviors and microstructures of C/SiC composites.3. The theories of chemical reaction kinetics and mass transport have been used to establish the oxidation models of composites in oxygen and oxygen/water vapor coupling environment, in which the functional relationships of the weight change of composites with the oxidation temperature and oxidation duration are illuminated.4. The software platform of factorization for the analysis of C/SiC composites oxidation behaviors has been developed based on the mathematical model offactorization method. The software can been used to adequately analyze the original experimental data and get the useful information hidden in the original data as well as forecast the weight change curves of C/SiC composites of different oxidation durations. Further research of factorization method has been done to make it possible to factorize the multi-variable goal function.