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针对燃气轮机高温透平叶片在Na、V、S环境的高温熔盐热腐蚀问题,采用低压等离子喷涂NiCoCrAlTaY和CoNiCrAlY涂层,通过组织结构分析和腐蚀试验,对比分析了两种涂层与IN 738高温合金的高温抗熔盐腐蚀性能。结果表明:低压等离子喷涂过程中两种涂层材料的氧化程度较弱。预氧化形成的致密连续的热生长氧化物(TGO)膜可延缓涂层发生腐蚀。随着腐蚀时间延长,预氧化形成的α-Al_2O_3被消耗,并逐渐产生Cr-Ni与Co-Ni等尖晶石氧化物以及硫化物。700℃腐蚀环境中两种涂层的腐蚀速率约为基体的1/10,900℃时约1/7,且NiCoCrAlTaY涂层的抗熔盐腐蚀性能略优于CoNiCrAlY涂层。
Aiming at the problem of high temperature hot molten salt corrosion of turbine blades in high temperature Na, V, S environments, low-pressure plasma spraying NiCoCrAlTaY and CoNiCrAlY coatings was carried out. The microstructures and corrosion tests of two coatings were compared with that of IN 738 High-temperature alloy corrosion resistance of molten salt. The results show that the oxidation of the two coating materials is weak during the low pressure plasma spraying. A dense and continuous thermal growth oxide (TGO) film formed by pre-oxidation can delay corrosion of the coating. With the prolongation of corrosion time, α-Al 2 O 3 formed by the pre-oxidation is consumed and spinel oxides such as Cr-Ni and Co-Ni and sulfide are gradually produced. The corrosion rate of the two coatings in the 700 ℃ corrosion environment is about 1/10 of that of the substrate and about 1/7 in the 900 ℃. The corrosion resistance of the NiCoCrAlTaY coating is slightly better than that of the CoNiCrAlY coating.