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采用等离子喷涂技术制备了常规和纳米MCrAlY/ZrO2-7%Y2O3(质量分数)双层系统热障涂层。比较了两种涂层的微观结构和850℃下75%Na2SO4+25%NaCl(质量分数)混合熔盐中耐热腐蚀性能,并探讨了涂层的热腐蚀破坏机理。结果表明,等离子喷涂常规和纳米热障涂层都为典型的层状堆积结构,但与常规涂层相比,纳米团聚体粉末喷涂过程中熔化充分,其涂层孔隙率低,组织更致密。两种涂层的热腐蚀破坏都是稳定剂Y2O3的消耗而引起的部分四方相转化为单斜相的马氏体相变,但总体上纳米热障涂层本身的热腐蚀程度要小于常规涂层,其对金属粘结层及基体的保护也更好。
Conventional and nano-MCrAlY / ZrO2-7% Y2O3 (mass fraction) two-layer system thermal barrier coatings were prepared by plasma spray technique. The microstructure of the two coatings were compared with that of the molten salt mixed with 75% Na2SO4 + 25% NaCl at 850 ℃, and the mechanism of hot corrosion damage of the coatings was also discussed. The results show that both plasma spraying and nano-thermal barrier coatings are typical layered structures. However, compared with the conventional coatings, the nano-aggregates powder is fully melted during spraying and the coating porosity is low and the structure is denser. The thermal corrosion damage of the two coatings are all caused by the consumption of the stabilizer Y2O3 martensitic transformation of a part of the tetragonal phase monoclinic phase, but the thermal corrosion of the thermal barrier coating itself is generally less than the conventional coating Layer, the metal adhesive layer and the substrate protection is better.