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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。
Applying high temperature ceramic coating on superalloy surface is an effective way to improve the high temperature performance of alloy. In this study, Al2O3-SiO2 composite sol was prepared by sol-gel method according to the ratio of aluminum to silicon molar ratio of 3: 2 and applied to the surface of Ni-based superalloy. In order to investigate the high-temperature oxidation characteristics of the coating, the coating was heat-treated at 1000 and 1200 ℃ for 20 hours and oxidized 20 times at 800 ℃ respectively. The microstructure of the coating surface and cross-section was observed by SEM. The structural changes of the gel were analyzed by infrared spectroscopy (FT-IR). The results show that the composite coating is tightly combined with the Ni-based superalloy substrate. The coating does not peel off after long-time heat treatment at 1000 ° C, and can undergo repeated heat treatment at 800 ° C with good high-temperature oxidation resistance.