SiCf/SiC复合材料高温水氧腐蚀性能研究

Research on High Temperature Water Oxygen Corrosion Performance of SiCf/SiC Composite Materials

采用2.5D方式编织SiCf/SiC复合材料预制体,CVI工艺制备PyC界面层,CVI-PIP复合工艺制备SiCf/SiC复合材料基体,在1300℃、50%水汽/50%O 2混合气体的条件下对SiCf/SiC复合材料进行高温水氧腐蚀试验,对SiCf/SiC复合材料在腐蚀前后的相成分变化及微观组织变化进行评价,并探讨了其在高温水氧腐蚀条件下的性能退化机理。结果表明,PyC界面层易被氧化生成气体产物从而留下间隙,该通道为外界腐蚀性气体如水汽、氧气进入复合材料内部侵蚀其纤维、基体等提供捷径。

SiCf/SiC composite preforms were woven using 2.5D method,PyC interface layer was prepared by CVI process,and SiCf/SiC composite matrix was prepared by CVI-PIP composite process.High temperature water oxygen corrosion tests were conducted on SiCf/SiC composite materials under the conditions of 1300℃,50%water vapor/50%O 2 mixture gas.The phase composition and microstructure changes of SiCf/SiC composite materials before and after corrosion were evaluated,and the performance degradation mechanism under high temperature water oxygen corrosion conditions was explored.The results indicate that the PyC interface layer is easily oxidized to generate gas products,leaving gaps.This channel provides a shortcut for external corrosive gases such as water vapor and oxygen to enter the interior of the composite material and corrode its fibers and matrix.