(1. 中南大学 材料科学与工程学院，长沙 410083；2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 采用电弧离子镀(AIP)技术在TC4 (Ti-6Al-4V) 钛合金基体表面沉积制备NiCrAlY涂层，测定TC4钛合金和NiCrAlY涂层在700~900 ℃的氧化动力学曲线。通过扫描电镜(SEM)、能谱(EDS)分析与X射线衍射分析 (XRD)研究TC4钛合金和NiCrAlY涂层氧化前后物相组成和组织形貌，讨论氧化过程中元素的扩散行为。结果表明：在700~900 ℃静态空气中氧化100 h，NiCrAlY涂层能明显提高TC4钛合金的抗氧化性能，TC4钛合金氧化后形成Al2O3层和TiO2层交替出现的氧化膜层；经700和800 ℃氧化后，NiCrAlY涂层保持其原始的相组成，但在表面形成Al2O3和Cr2O3混合氧化膜；经900 ℃氧化后，氧化膜由Al2O3和TiO2组成；经700 ℃氧化时，主要发生Ti和Ni两种元素的扩散；经800和900 ℃氧化时，由于Ti及Ni元素的剧烈扩散，界面附近出现Kirkendall疏孔带和约100 μm的β相稳定区；经900 ℃氧化时，Ti扩散到涂层表面形成氧化物导致氧化速率提高，Cr元素开始向基体扩散并在近界面处富集。
关键字: NiCrAlY涂层；TC4钛合金；氧化；扩散
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;2. Key Laboratory of Nonferrous Metals Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The NiCrAlY coating was deposited on TC4 titanium alloy by arc ion plating (AIP). The oxidation kinetic curves of TC4 titanium alloy and NiCrAlY coating were obtained. The microstructures and morphologies of TC4 alloy and NiCrAlY coating before and after oxidation were analyzed by SEM, EDS and XRD, and the elements diffusion behavior was also studied. The results show that the oxidation resistance of TC4 alloy is evidently improved by NiCrAlY coating at 700−900 ℃. The oxidation layer of TC4 consists of TiO2 and Al2O3 layers alternately. After oxidation at 700 and 800 ℃, NiCrAlY coating still contains the original phases and the oxidation produces are made up of Al2O3 and Cr2O3. At 900 ℃, the oxidation coat consists of Al2O3 and TiO2. At 700 ℃, Ti and Ni are the major diffusion elements. Because of the violent diffusion of Ti and Ni, Kirkendal porosity belts and β-stabilizes zones appear near the interface at 800 and 900 ℃. At 900 ℃, Ti diffuses to the coating surface and form TiO2, which increases the oxidation speed. Cr begins to diffuse to the substrate and accumulates at the interface at 900 ℃.
Key words: NiCrAlY coating; TC4 titanium alloy; oxidation; diffusion
