Modeling the Oxidation and Corrosion Behavior of 3D Carbon Fiber Reinforced SiC Matrix Composites from 400 to 1500 Degrees C

Abstract

SiC coated three-dimensional textile carbon fiber reinforced SiC matrix composites (3D C/SiC) are promising materials for high temperature from 400 to 1500degreesC, oxidizing and corroding environment. In different temperature range from 400 to 1500degreesC, the oxidation and corrosion mechanisms of 3D C/SiC are quite different at different pure or mixed atmosphere including oxygen, water and sodium sulfate. The quality of SiC coating, which can be characterized with deposition times, thickness and grain size, is a key factor that effects on the weight change of the composites working in an environment. The environmental effects on the weight change of the composites have been studied through a series of oxidation and corrosion experiments. Quantitative models were developed based on the mechanism analyses and experimental data, which can predict the weight change of composites with different SiC coating in pure and mixed gaseous atmosphere from 400 to 1500degreesC. Oxygen and water are the controlling factors below and above 950degreesC, respectively. Na2SO4 causes a relatively great weight loss of C/SiC above 1300degreesC. Four layers of SiC coating with the total thickness of 80 microns can improve the oxidation and corrosion resistance of 3D C/SiC.