电弧离子镀NiAlHf涂层的抗高温氧化性能

High Temperature Oxidation Resistance Performance of NiAlHf Coating Prepared by Arc Ion Plating

目的通过电弧离子镀技术,获得抗氧化性能优良的NiAl涂层。方法采用电弧离子镀技术,在弧流为110 A,偏压为-50 V的参数下沉积NiAlHf涂层。通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对涂层的物相结构和形貌进行分析,通过能谱仪(EDS)分析涂层的成分。采用恒温氧化增重实验对涂层的氧化动力学进行分析。结果由电弧离子镀技术制备的NiAl涂层致密均匀,无大颗粒、孔洞等缺陷。涂层主要由β-NiAl相组成,活性元素Hf固溶在主相中。NiAlHf涂层表现出良好的抗高温氧化性能,动力学曲线符合抛物线规律,在1150℃下恒温氧化200h的平均氧化速率为0.0841g/(m^2×h),远优于传统MCrAlY涂层体系。NiAlHf涂层在氧化初期形成保护性的α-Al2O3氧化皮以及少量亚稳态的θ-Al2O3,随后θ-Al2O3逐渐转变为稳态的α-Al2O3。Hf在涂层表面富集从而形成HfO2,对氧化皮形成了钉扎作用,增强了氧化皮的粘附性,提高了涂层的抗氧化性能。随着氧化的进行,涂层中的β-NiAl相逐渐转变为γ'-Ni3Al相。结论 NiAlHf涂层在1150℃下仍具备优良的抗高温氧化性能,对下一代耐更高温度涂层开发,电弧离子镀NiAl涂层的技术推广及工业化应用有一定的指导作用。

In order to obtain a NiAl coating with excellent oxidation resistance, NiAlHf coating was prepared on nickel-base superalloy by arc ion plating technology. The arc ion plating technology was used to deposit NiAlHf coating under the parameters of arc current of 110 A and bias voltage of -50 V. The phase structure and morphology of the coating were analyzed by X-ray diffractometer(XRD) and scanning electron microscope(SEM), and the composition of the coating was analyzed by energy spectrometer(EDS). Constant temperature oxidation weight method was adopted to evaluate the high temperature oxidation resistance of the coating. Results show that the NiAlHf coating is dense uniform without obvious holes and other defects. The coating were mainly composed of β-NiAl, and the active element Hf is dissolved in the main phase. The coatings has good high temperature oxidation resistance, the average oxidation rates of NiAlHf coatings after 200 h were 0.0841 g/(m2·h) at constant temperature of 1150 ℃, which is far superior to the traditional MCrAlY coating system. The α-Al2O3 and θ-Al2O3 phase mainly formed at the initial stage of oxidation, then the transition from θ-Al2O3 to the stable α-Al2O3 occurred. Hf is enriched on the coating surface to form HfO2, which forms a pinning effect on the oxide scale, enhances the adhesion of the oxide scale, and improves the oxidation resistance of the coating. With the progress of oxidation, the β-NiAl phase in the coating gradually changed to the γ’-Ni3Al phase. The NiAlHf coating still has excellent oxidation resistance at 1150 ℃, which has a certain guiding role for the development of next advanced protecting coatings, promotion and industrial application of the arc ion plating technology of the NiAl coating.