等离子喷涂TiB_(2)-SiC复合涂层及其热稳定性研究

The plasma sprayed TiB_(2)-SiC composite coating and its thermal stability

利用喷雾干燥重构微米级TiB_(2)-SiC喷涂团聚粉,借助等离子喷涂成功制备了TiB_(2)-SiC复合涂层。结果表明,包覆结构可减缓SiC高温分解,获得TiB_(2)、SiC主相共存的复合涂层。通过显微硬度测定及Weibull分布发现,当SiC质量分数为5%时,复合涂层的平均显微硬度为1088.8 Hv_(0.2),分散性系数β为9.2,均高于含20 wt%SiC制备的涂层,表明其具有更稳定的性能和结构。通过900℃和1000℃高温热冲击性及抗氧化性能测定发现,TiB_(2)-5 wt%SiC制备的复合涂层具有更为优异的抗热冲击性能和抗高温氧化性能。

In this paper,micron scale TiB_(2)-SiC agglomerate powders were reconstructed by spray drying,and the TiB_(2)-SiC composite coatings were successfully prepared by plasma spraying.The results show that the cladding structure of TiB_(2)-SiC agglomerates can slow down the high decomposition of SiC.Accordingly,the as-sprayed composite coatings are TiB_(2) and SiC main phases co-existence.Based on the microhardness measurement and Weibull distribution of composite coatings,it is found that when the mass fraction of SiC is 5 wt%SiC,the average microhardness of composite coating is 1088.8 Hv_(0.2) and the dispersion coefficientβis 9.2.Both of them are higher than the coating containing 20 wt%SiC,which indicates that it has more stable properties and structure.The composite coating prepared by TiB_(2)-5 wt%SiC has better thermal shock resistance and high temperature oxidation resistance through the determination of thermal shock resistance at 900℃and 1000℃.