镍基合金表面Al-Co共渗涂层制备

利用包埋渗法在镍基高温合金表面成功制备了Al-Co涂层.涂层为单层结构,显示出均匀、致密的特性,涂层主要由AlNi相、AlCo相和Al-Cr间金属化合物组成.涂层中Al和Co的含量明显高于基体中两元素的含量.基体与涂层之间有一层与涂层厚度相当的过渡层,过渡层是由于其内部的Al元素向外扩散导致Cr,W,Mo,Ti等元素析出而形成的.过渡层与基体和涂层之间的结合都较为紧密,达到了冶金结合.

Preparation of Al-Co codeposition coating on surface of Ni-based alloy

A novel Ni-Al-Co coating was developed through pack cementation for protection of superalloys. Surface and cross-sectional observations of the coated specimens were preformed on a scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). X-ray diffraction (XRD) was used in order to detect the phases formed. The results show that the developed Ni-Al-Co coating, which is mainly composed of AlNi, AlCo and Al-Cr intermetallics, shows monolayer structure. The contents of Al and Co are obviously higher than that in the substrate. Furthermore, an interdiffusion layer has been developed between the Ni-Al-Co coating and the substrate. The interdiffusion layer shows good adherence on the substrate because no cracks and spalling was detected at the interface between the interdiffusion layer and the substrate. The formation of the interdiffusion layer may be induced by the precipitation of the elements of Cr,W,Mo,Ti during the pack cementation.