NiCoCrAlYTa涂层与镍基高温合金基体互扩散行为研究

Study of the Inter-diffusion Behavior between NiCoCrAlYTa Coating and Ni-based Superalloy Substrate

采用大气等离子喷涂技术(APS)在镍基高温合金GH536上制备Ni Co Cr Al YTa涂层。通过SEM、EDS等方法研究了Ni Co Cr Al YTa涂层与合金基材在1000℃下界面的元素或扩散行为及涂层组织演变规律。结果表明:随着氧化时间延长,涂层中的Co、Al及基材中的Fe、Mo发生了明显的互扩散,涂层中发生了β→γ’→γ的相转变。氧化500h后,元素Y、Ta扩散到了涂层氧化膜中,靠近界面处的涂层基体中出现了大量横向排列、尺寸在5μm左右的富Ta相,形成了一个扩散障,减缓了涂层与基材之间元素互扩散。

The NiCoCrAlYTa coatings were prepared on Ni-based superalloy GH536 by Air plasma spraying （APS）. The inter-diffusion behavior and microstructural evolution at 1000 ℃were analyzed by SEM and EDS. The results indicate that the elemental inter-diffusion between coating and substrate occurs as Al, Co in coating diffuse inward the substrate and Fe, Mo in the substrate diffuse into the coating. Meanwhile, phase transition ofβ → γ’ → γhappened in coatings. After 500h oxidation, Y and Ta diffused into the oxidation film on the top of coatings. A mass of Ta-rich phase which size at about 5μm lined closed to the interface of coating and substrate, it would help to slow down the elemental inter-diffusion between coating and substrate.