超音速火焰喷涂制备Cr_2AlC涂层组织性能研究

Microstructure and Performance of Cr_2AlC Coatings Deposited by HVOF Spraying

采用真空分段烧结法制备了两种不同粒度的高单相Cr2AlC化合物粉末,并使用超音速火焰喷涂(HVOF)方法在GH4169高温镍合金上制备了Cr2AlC涂层,对喷涂粉末及涂层进行了相结构分析,测试了涂层的显微硬度、孔隙率,并采用扫描电子显微镜(SEM)对喷涂粉末及涂层截面形貌进行了观察,结合扫描电镜能谱仪(EDS)和X射线衍射研究了涂层相组成,分析了粉末粒度对涂层微观组织结构的影响。研究结果表明:采用超音速火焰喷涂成功制备了厚度超过200μm的Cr2AlC涂层,涂层与基体紧密结合,涂层微观组织致密,采用较细的粉末有利于得到更高致密度的涂层。在喷涂过程中,有少量Cr2AlC粉末发生分解形成Cr7C3化合物。

The Cr2AIC coatings were prepared by high velocity oxy-fuel （HVOF） on GH4169 super-alloy with two different particle sizes Cr2 A1C powders synthesized by vacuum segment sintering. The phase structure of the powder and coatings were analyzed by using X-ray diffraction, the micro-hardness of the coatings was measured by micro-indentation, the porosity was determined from the optical micrograph, the powers and section morphology of the coatings were observed by SEM, phase composition was determined by EDS and XRD and the effect of power sizes to micro-phase structure of the coatings was analyzed. The result showed that the Cr2 AIC coating with thickness more than 200 μm was prepared successfully by using HVOF, the coating was closely combined with the matrix, the micro- structure of the coating was dense, and the higher density of the coating could be obtained by using smaller particle size of the powders. Meanwhile, a small amount of Cr2A1C powder was decomposed into Cr7C3 compound during the HVOF spraying.