Ni基高温合金表面涂覆Al_2O_3-SiO_2涂层的高温氧化特性研究(英文)

Study of High Temperature Oxidation Properties of Al_2O_3-SiO_2 Ceramic Coatings on Nickel Superalloy

在高温合金表面涂覆耐高温陶瓷涂层是一种提高合金高温性能的有效方法。本研究按照铝、硅元素摩尔比3:2的比例,采用溶胶-凝胶法制备Al2O3-SiO2复合溶胶,并涂敷于Ni基高温合金表面。为考察该涂层的高温氧化特性,分别对涂层进行1000和1200℃下20h长时热处理和800℃循环氧化20次试验。利用SEM观察涂层表面和截面的微观状态,利用红外光谱(FT-IR)分析凝胶的结构变化。结果表明,复合涂层与Ni基高温合金基体间结合紧密,在1000℃长时间热处理后涂层无明显剥落,并可经历800°C多次热循环处理,具有良好的耐高温氧化特性。

High-temperature ceramic coating on superalloy surface is a good method to improve high temperature performance of metal. Alumina-silica composite ceramic coatings were obtained on nickel superalloy substrates with the molar ratio of mullite by a sol-gel coating process according to hydrolytic condensation of organic alkoxide of aluminum and silicon elements. The oxidation behavior of the coatings was investigated by 1000 and 1200℃ heat treatment in the air for 20 h and by 20 times circular oxidation tests at 800 ℃. The microstructure and states of coatings on the surface and section of nickel superalloy were observed by scanning electron microscope (SEM). The structural change of gels was analyzed by Fourier transform infrared (FT-IR) spectroscopy. The results show that there is an adhesive layer between the coating and the alloy substrate. Moreover, the disjuncting layer became blurred after long period of high temperature treatment. Alumina-silica composite ceramic coatings demonstrate excellent long-term performance at a high temperature of 1000℃ and repetitious thermal cyclic oxidation at 800℃.