APS制备SiC/Al2O3复合陶瓷涂层组织结构及抗烧蚀性能的研究

摘要

针对APS制备SiC涂层沉积率低、孔隙率高、在烧蚀考核的过程中出现基体C/C材料被氧化烧蚀的问题,本文设计制备了SiC/Al2O3复合陶瓷团聚粉末,采用APS在C/C表面制备了相应的SiC/Al2O3复合陶瓷涂层,并选用氧乙炔在1500 ℃对涂层进行了抗氧化烧蚀性能考核.利用XRD、SEM等检测分析手段对团聚粉末以及涂层的成分及组织进行检测.结果表明,通过在SiC粉末中添加Al2O3粉末(SiC:Al2O3为3:2),提高了团聚粉末的沉积率以及涂层的致密度,其原因是等离子喷涂过程中Al2O3液相对SiC具有良好的包袱保护效果,避免了SiC的分解问题.烧蚀实验表明涂层可以在1500 ℃烧蚀5 min后,涂层完整,证明氧化物的添加可以封堵孔洞并且抑制氧气的扩散,从而提高涂层抗烧蚀性能.%To solve the low deposition rate,high porosity ,C/C was ablated during ablation process problem of SiC coating deposited by APS.SiC/Al2O3 composite ceramic reunion powder was designed and prepared,and composite ceramic coating was deposited by APS.The coating was tested by oxyacetylene flame at 1500 ℃.Microstructure and composition of the reunion powder and coating were detected by XRD, SEM .The results show that the addition of Al2O3 in SiC increases the deposition rate and the density of the SiC coating.And it's because of Al2O3 has good high temperature filling effect in the APS process.Al2O3 can ease the stress, reduce coating cracking during cooling process due to thermal expansion coefficient does not match.Ablation experiment shows that the coating is integrity after ablated at 1500 ℃ for 5 minutes,proves that the addition of oxides can block holes and inhibit the diffusion of oxygen, thus improve the anti-ablation properties of SiC coating.