Ni-Cr-W高温合金渗铝涂层1100 ℃恒温氧化行为

Isothermal Oxidation Behaviors of Packed Aluminide Coatings of Ni-Cr-W Superalloy at 1100 °C

摘要:

系统地研究了Ni-Cr-W高温合金铝覆涂层在1100 ℃的恒温氧化行为。利用扫描电子显微镜（SEM）和X射线衍射（XRD）等技术对试样进行观察与分析。结果表明，铝覆涂层的氧化动力学曲线分为初期快速氧化阶段和中后期缓慢平稳氧化阶段。在整个氧化过程中，铝覆涂层表面形成的氧化物经历了由晶须状的θ-A12O3→等轴的α-A12O3→α-A12O3→颗粒状α-A12O3→颗粒状团聚α-A12O3变化过程。碳化物在氧化初期可有效阻止由Ni和Al元素的互扩散所引起的涂层退化。

Abstract:

The isothermal oxidation behavior of packed aluminide coatings of Ni-Cr-W superalloy at 1100 oC was investigated. Results from scanning electron microscopy and X-ray diffraction indicate that the oxidation dynamics curve of packed aluminide coatings can be divided into two stages: initial rapidly stage and metaphase slowly stage. Oxides on packed aluminide coatings surface have a transformation process as following: crystal θ-A12O3→equalaxial α-A12O3→α-A12O3→particle α-A12O3→particle unite α-A12O3 during the whole oxidation. During the initial stage of oxidation, carbides can be able to holdback coating degeneration caused by interdiffusion between Ni element and Al element.