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利用料浆熔烧法在航天发动机用铌钨合金表面制备了高温抗氧化涂层,通过扫描电镜(SEM)和能量弥散X射线谱(EDX)等手段分析观察涂层表面、断面微观形貌及涂层组成,由上述分析结果阐述了铌钨合金表面高温抗氧化涂层常见的表面缺陷、涂层色差的形成机制及其对涂层在高温有氧环境中的性能和表面质量的影响。通过一系列的研究发现涂层色差的形成是由于涂覆过程中料浆过剩,熔烧制备过程中过剩料浆在涂层表层反应生成硅化物富集,形成不同于正常涂层的晶粒,由此导致了涂层色差的出现,涂层色差只存在于涂层表层,它的存在并不改变涂层其他层次的结构和成分,对涂层整体的厚度及表面质量都没有影响,而且在高温有氧环境中进行测试发现,有色差和没有色差的涂层高温性能相差不大,由此表明涂层色差的存在并不影响涂层的高温性能。
High-temperature anti-oxidation coating was prepared on the niobium-tungsten alloy surface of aerospace engine by slurry melting method. The surface and cross-section microstructure of the coating were observed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) Based on the above analysis results, the common surface defects, the formation mechanism of the coating color difference and the influence on the performance and surface quality of the coating in the high temperature aerobic environment are described. Through a series of studies, it is found that the formation of coating color is due to excess slurry in the coating process. Excess slurry in the process of melting and sintering reacts on the coating surface to form silicide enrichment to form grains different from the normal coating, Which led to the appearance of coating color, coating color difference exists only in the coating surface, its presence does not change the structure and composition of the other layers of the coating, the overall thickness of the coating and surface quality have no effect, and in High temperature aerobic environment test found that there is no difference between the color difference and no color difference of the coating high temperature performance, indicating that the presence of coating color does not affect the coating’s high temperature performance.