真空热处理对NiCoCrAlTaY涂层／Ti62421S钛合金界面组织结构及元素扩散行为的影响

采用电弧离子镀（AII））技术在Ti62421s钛合金基体表面沉积NiCoCrAlTaY涂层。通过XRD、SEM与EDS能谱分析研究了不同真空热处理制度下NiCoCrAlTaY涂层／Ti62421s基体界面显微组织的变化和元素扩散行为。结果表明：沉积态的涂层主要由Cr2Ni3相、Al4Ni15Ta相和NiCoCr相组成。从750℃开始，NCoCrAlTaY涂层和钛合金基体有明显的界面反应，850℃真空热处理后界面出现明显的分层，析出Ni3（A1，Ti）、Ti（Ni，Co）和Ti2（Ni，Co）相；随着温度的升高，界面分层并加厚，同时出现kirkendall空位带，导致涂层退化。经950℃退火后涂层剥落，只有TiCr4相。650℃／3h、750℃／3h真空热处理过程中，涂层／基体界面发生Ni、Co、Ti元素互扩散，涂层中Ta和cr元素基本未向基体扩散。

Effect of Vacuum Heat Treatment on Microstructure and Elements Diffusion Behavior of NiCoCrAITaY Coating on Ti62421s

The arc ion plating （AIP） was used respectively to prepare NiCoCrA1TaY coating on Ti62421s alloy. XRD. SEM. EDS were used to analyse and disscuss the influence of interface organization and diffusion behavior through vacuum heat--treatment at different regime. The results indicate that： The deposited NiCoCrA1TaY coating was mainly made up of Cr2 Ni3. Al4 Ni15 Ta and NiCoCr phase, there were obvious reactions after 750℃ vacuum heat treatment, the interface became several layers at 850℃, Ni3 （Al, Ti）. Ti （Ni, Co） and Tiz （Ni, Co） phase was precipited in the coating; With heat treatment temperature increasing, the interface became thicker and kirkendall voids belts were found lead to the degradation of coating, from 950℃ coating was peeling, and only TiCr4could be found at 950℃. After 650℃/3h, 750℃/3h vacuum heat treatment, Ni, Co, Ti element interdiffuse in the coating/substrate interface, elements Ta and Cr in the coating are not dif- fused to the substrate.