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采用料浆法在镍基高温合金。M951上制备Al-Si共渗涂层,研究了合金及涂层样品在1100℃恒温、循环氧化及在850℃在Na_2SO_4+25%K_2SO_4和Na_2SO_4+25%NaCl两种混盐中的热腐蚀行为。同时利用SEM、EDS对氧化膜表截面形貌进行了观察,并结合X射线衍射对相组成进行了分析。结果表明,在1100℃恒温及循环氧化时,M951合金表面生成NiO、NiAl_2O_4、Nb_2O_5及A1_2O_3等的混合氧化物膜,氧化膜不均匀且剥落严重。在Al-Si涂层样品表面形成稳态的α-A1_2O_3,大幅度提高了合金的抗高温氧化性能。在850℃热腐蚀试验中,M951合金40 h后发生灾难性腐蚀,而Al-Si涂层经100 h腐蚀后仍保持完整,表面形成极薄且连续的θ-A1_2O_3氧化膜,大幅度提高了合金的抗热腐蚀性能。
Using slurry method in the nickel-based superalloy. M951 was used to prepare the Al-Si co-permeable coating. The corrosion behavior of the alloy and coating at 1100 ℃, cyclic oxidation and 850 ℃ for two mixed salts of Na_2SO_4 + 25% K_2SO_4 and Na_2SO_4 + 25% NaCl were investigated. . At the same time, SEM and EDS were used to observe the morphology of oxide film. The phase composition was analyzed by X-ray diffraction. The results show that mixed oxide films such as NiO, NiAl_2O_4, Nb_2O_5 and Al_2O_3 are formed on the surface of M951 alloy at 1100 ℃ with constant temperature and cyclic oxidation. The oxide film is not uniform and the peeling is serious. The formation of steady-state α-Al 2 O 3 on the surface of Al-Si coating samples greatly improves the high-temperature oxidation resistance of the alloy. In the hot corrosion test at 850 ℃, the M951 alloy suffered catastrophic corrosion after 40 h, while the Al-Si coating remained intact after 100 h of corrosion, forming a very thin and continuous θ-A1_2O_3 oxide film on the surface, greatly improving the Hot corrosion resistance of alloy.