C/C复合材料ZrSi2-TaB2-SiC复合涂层的组织结构与性能

Microstructure and Properties of ZrSi_(2)-TaB_(2)-Si C Composite Coatings on C/C Composites

采用三次包埋法在C/C复合材料表面制备了ZrSi_(2)-TaB_(2)-SiC复合涂层。对其进行了1500℃静态抗氧化实验和抗热震性能测试,借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS),对涂层氧化前后的组织结构和微观形貌进行表征。结果表明:所制备的ZrSi_(2)-TaB_(2)-SiC复合涂层外层疏松内层致密,涂层与涂层之间以及涂层与基体之间相互嵌合,且生成的(Zr,Ta)B_(2)固溶体相均匀嵌布在涂层中。该涂层在1500℃静态空气中保护基体168 h,质量损失率只有2.91%;经历从室温到1500℃的热循环30次,质量损失率仅3.10%,具有优异的静态抗氧化和抗热震性能。这归功于ZrSi_(2)-TaB_(2)-Si C复合涂层的结构,以及涂层氧化后生成Zr-Ta-Si-O复相玻璃层。在高温下,稳定的高熔点ZrO_(2)、Ta_(2)O_(5)和ZrSiO_(4)作为“镶嵌相”弥散在玻璃相中,起到“钉扎”作用,提升了涂层的抗氧化性能。

ZrSi_(2)-TaB_(2)-SiC composite coatings were prepared on the surface of C/C composites by process of pack cementation.The results show that the ZrSi_(2)-TaB_(2)-SiC composite coating loose outer layer and dense inner layer,and the bonding between the coating and the coating and between the coating and the substrate is tight.(Zr,TA)B2 solid solution phase is evenly embedded in the coating.The coating protects the substrate for 168 hours in static air at 1500℃,and the weight loss rate is only 2.91%;after 30 thermal cycles from room temperature to 1500℃,the weight loss rate is only 3.10%,indicating that it has excellent static oxidation resistance and thermal shock resistance.It’s due to the formation of Zr-Ta-Si-O multiphase glass layer after oxidation of the coating.ZrO_(2),Ta_(2)O_(5) and ZrSiO4 have high melting point,dispersed in the glass phase as“mosaic phase”,which plays a pinning role at high temperature,improves the oxidation resistance of the coating.