炮钢表面电弧离子镀NiCrAlY涂层950℃的高温氧化行为

High-temperature Oxidation Behavior of Arc Ion Plated NiCrAlY Coating on Gun Steel at 950 ℃

用电弧离子镀方法在炮钢表面制备NiCrAlY涂层,涂层在空气中950℃恒温氧化100h,借助X-射线衍射仪、扫描电镜和能谱仪对涂层表面氧化膜进行分析,检测其高温抗氧化能力。结果表明,电弧离子镀NiCrAlY涂层950℃空气中氧化100h后表面形成Al2O3、Fe2O3和NiCr2O4三种氧化物,涂层大大提高了炮钢的高温抗氧化性;涂层中的Ni元素与基体中的Fe元素发生剧烈互扩散而在界面两侧呈均匀梯度分布,Cr元素在界面富集,Al元素在界面与O反应形成较致密的Al2O3氧化层;由于扩散和氧化作用,涂层中的相由原来的β-NiAl、γ'-Ni3Al、γ-Ni与α-Cr变为γ'-Ni3Al、(Ni,Fe)、(Fe,Ni)与α-Cr。

NiCrAlY coating was deposited on gun steel substrate by arc ion plating method,and then the coating was oxidized at 950 ~C in air for 100 h. Oxidation behavior of the coating was tested through analyzing the oxide film by XRD, SEM and EDAX techniques. Results showed that during the oxidation process, oxidation film with composition of Al2O3、Fe2O3 adn NiCr2O4 was formed on the coating, and substantially increased the high-temperature oxidation resistance. The obvious interdiffusion between Fe atom in substrate and Ni atom in NiCrA1Y coating was occurred, and Fe and Ni elements distributed gradiently along the two sides of interface. Meanwhile, Cr element was mainly distributed near the interface and Al atom was reacted to O atom to form a compact Al2O3 layer at the interface.β-NiAl,γ＇-Ni3Al,γ-Ni and α- Cr phases in the coating were transformed to γ＇-Ni3 AI, （Ni, Fe）, （Fe, Ni） and α-Cr phases because of the synergetic effects of oxidation and diffusion.