HCPEB作用下镀铝CoCrAlY涂层的表面微观结构状态

采用大气等离子喷涂在GH4169镍基高温合金表面沉积CoCrAlY涂层，利用电子束蒸发镀膜技术在涂层表面沉积纳米铝膜，分别对镀铝前后的涂层使用强流脉冲电子束进行辐照处理，对处理前后的涂层表面进行成分及结构分析.XRD结果显示，经过HCPEB轰击之后，涂层表面纳米铝膜重熔，钴类氧化物消失，新增铝相，且随着轰击次数增加，β-CoAl含量增加.结构分析表明，电子束轰击可以使原始涂层表面尖角、孔洞、夹杂等消失，形成非常致密的凸起胞状体纳米超细晶结构，有利于抑制腐蚀性气体的侵入，同时铝含量的增加有利于抗氧化性能的提高.

Surface microstructure of aluminized CoCrAlY coating irradiated by high current pulsed electron beam

A thermally sprayed CoCrAlY coating was prepared by air plasma spray on Ni-based superalloy GH4169, then a nano-scale Al film was deposited by electric beam evaporation. The coating was subjected to a high current pulsed electron beam. After HCPEB treatment, the Al film was remelted. The XRD result showed that Al phase was formed in the irradiated coatings, and the original Co-based oxide disappeared, but the content of β-CoAl was increased with the increase of irradiated pulses. Microstuctural observations revealed that the original coating with porosity, cavities and inclusions was significantly changed to a compact appearance with interconnected bulged nodules after HCPEB treatment. Moreover, the grains on the irradiated coating were very refined and homogeneously dispersed on the surface, which could effectively inhibit the infiltration of corrosive gases and improve the oxidation resistance of coating.