铌合金表面硅化物涂层热震行为研究

Study on Thermal Shock Behavior of Silicide Coating on Niobium Alloy

为提高铌合金高温抗氧化性能,采用复合包渗法在Nb521合金表面制备了以MoSi2为主体的硅化物涂层,对涂层进行了室温-1650℃热震试验,利用XRD,SEM,EDS以及EPMA等检测手段对热震前后涂层组织结构变化进行了分析,观察了裂纹扩展过程。结果表明：涂层室温-1650℃有效抗热震次数可达600次;热震过程中,元素扩散导致涂层组织结构发生明显改变;Nb5Si3低硅化物层的产生对裂纹扩展有重要影响。

Abstract： A kind of silicide coating with MoSi2 as the main layer was prepared by complex pack cementation metallization on Nb521 alloys, and the thermal shock resistance was tested from room temperature to 1650 ℃ in air, and the structures of coating were observed and analyzed by means of XRD, SEM, EDS and EPMA, and the crack propagation behavior was investigated particularly. The conclusions were as follows. The coating could bear thermal shock for 600 times from room temperature to 1650 ℃ in air, and diffusion of elements led to the alteration of coating structures, and the crack propagation behavior was obviously affected by the growth of NbsSi3 silicide.