摘要
采用电弧离子镀在高温合金表面沉积Al-Cr-O/Zr-O多层涂层和Al-Cr-O单层涂层+NiCoCrAlSiY结合层,并在1000~1200℃下进行热处理。利用扫描电子显微镜和X射线衍射仪分析涂层的显微组织和物相结构。结果表明,Al-Cr-O/Zr-O多层涂层和Al-Cr-O单层涂层均呈现出致密的球形结构。热处理后,Al-Cr-O/Zr-O涂层表面出现裂纹,且裂纹随着温度的升高而增多和变粗。然而,Al-Cr-O涂层经热处理后其表面胞状结构转变为紧密连接的粒状结构,并且随着热处理温度的升高,粒状结构显著长大。由于作为氧离子导体以及t-ZrO_(2)的致密度低于α-Al_(2)O_(3),Al-Cr-O/Zr-O涂层中的t-ZrO_(2)为氧离子向涂层内扩散提供了通道,因此,Al-Cr-O单层涂层+NiCoCrAlSiY涂层体系的高温抗氧化性优于Al-Cr-O/Zr-O多层涂层+NiCoCrAlSiY涂层体系。但是,由于更大的陶瓷涂层厚度,t-ZrO_(2)相的低热导率以及层间界面的热反射作用,Al-Cr-O/Zr-O多层涂层+NiCoCrAlSiY涂层体系的隔热性能优于Al-Cr-O单层涂层+NiCoCrAlSiY涂层体系。
Al-Cr-O/Zr-O multilayer coating+NiCoCrAlSiY bond layer and Al-Cr-O single-layer coating+NiCoCrAlSiY bond layer were deposited on superalloy by arc ion plating,and subsequently they were heat treated at 1000-1200°C.Scanning electron microscope and X-ray diffractometer were used to analyze the microstructure and phase of the coatings.The results showed that both the Al-Cr-O/Zr-O multilayer coating and Al-Cr-O single-layer coating exhibited a compact spherical structure.After heat treatment,cracks occurred on the surface of Al-Cr-O/Zr-O coating.Cracks increased and widened with rising the temperature.However,the surface cell clusters of Al-Cr-O coating after heat treatment were changed to tightly connected granular structures,and the granular structures grew up significantly with the increase of annealing temperature.Owing to the oxygen ion conductor and lower densification of t-ZrO2 than α-Al_(2)O_(3),t-ZrO_(2) in the Al-Cr-O/Zr-O coating provided an access for the inward diffusion of oxygen.Therefore,the high temperature oxidation resistance of the Al-Cr-O coating+NiCoCrAlSiY layer was superior to that of the Al-Cr-O/Zr-O multilayer coating+NiCoCrAlSiY layer.The thermal insulation performance of Al-Cr-O/Zr-O multilayer coating+NiCoCrAlSiY layer was better than that of Al-Cr-O coating+NiCoCrAlSiY layer due to the large thickness and low thermal conductivity of t-ZrO2 phase and the heat reflection of interlayer interface.
作者
鲜丽君
赵海波
范洪远
鲜广
Li-jun XIAN;Hai-bo ZHAO;Hong-yuan FAN;Guang XIAN(School of Mechanical Engineering,Sichuan University,Chengdu 610065,China;Analysis and Testing Centre,Sichuan University,Chengdu 610065,China)
基金
the financial support of this research by the National Defense Science and Technology Key Laboratory Fund Project,China(No.6142212180103)。
