SiC涂层对熔渗SiC_(f)/SiC复合材料高温服役性能的影响  

Effect of SiC Coating on High-Temperature Service Performance of SiC_(f)/SiC Composite Prepared via Melt Infiltration Process

作　　者：刘虎 齐哲 艾莹珺 周怡然 杨金华 赵文青 赵春玲 郎旭东 贺宜红 焦健 LIU Hu;QI Zhe;AI Yingjun;ZHOU Yiran;YANG Jinhua;ZHAO Wenqing;ZHAO Chunling;LANG Xudong;HE Yihong;JIAO Jian(National Key Laboratory of Advanced Composites,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,Hunan,China)

机构地区：[1]中国航发北京航空材料研究院先进复合材料科技重点实验室,北京100095 [2]中国航发湖南动力机械研究所,湖南株洲412002

出　　处：《材料导报》2022年第21期72-76,共5页Materials Reports

摘　　要：采用化学气相沉积法(CVD)在熔渗制备的SiC_(f)/SiC复合材料表面沉积了SiC涂层,通过高温氧化试验研究了涂层对复合材料高温服役性能的影响,结果表明:在1200℃空气环境中氧化100 h后,无涂层试样的室温平均弯曲强度为424 MPa,弯曲强度下降了36.2%;而有涂层试样的室温平均弯曲强度为631 MPa,弯曲强度仅下降6.9%。SEM和XRD表征显示,无涂层试样中SiC纤维的氧化和BN界面层的退化失效是复合材料弯曲性能下降的重要原因,断口纤维拔出较少,呈脆性断裂特征;而有涂层试样表面氧化生成SiO_(2)氧化膜,其厚度增加过程服从抛物线规律。由于SiC层的封闭保护作用,复合材料试样受到的氧化作用较小,弯曲性能更好,断口纤维拔出明显。SiC coating was prepared by chemical vapor deposition(CVD)on the surface of SiC_(f)/SiC composite manufactured by melt-infiltration.The effect of SiC coating on the high-temperature service performance of the SiC_(f)/SiC composite was studied.The bending test results show that the average bending strength at ambient temperature for samples with and without SiC coating were 631 MPa and 424 MPa after oxidation at 1200℃in air for 100 h,which were reduced by 6.9%and 36.2%,respectively.The test specimen without SiC coating undergoes brittle fracture with very few fibers pulled out.The severer degradation of their flexural strength could be ascribed to the oxidation of SiC_(f)ibers and degradation of BN interphase,as analyzed by SEM and XRD.As for the samples with SiC coating,silicon dioxide film was formed on the outer surface of the coating after thermal exposure and its growth follows the parabolic rate law.The samples were subjected to comparatively slighter oxidation and displayed better flexural strength due to the protection from the SiC coating,and also significant pull-out of fibers could still be observed on the fracture surface.

关 键 词：SICF/SIC复合材料 SIC涂层 抗氧化性能 

分 类 号：TB332[一般工业技术—材料科学与工程]