(NiCoCrAlYSiB+AlSiY)复合涂层热腐蚀行为的研究

采用电弧离子镀（AIP）技术在镍基单晶高温合金基体上制备了NiCoCrAlYSiB涂层（普通涂层）和（Ni-CoCrAlYSiB+AlSiY）复合涂层,研究了高温合金基体与2种涂层分别在900和700℃下的涂盐（Na₂SO₄+K₂SO₄和Na₂SO₄+NaCl）热腐蚀行为.结果表明:高温（900℃）热腐蚀条件下,基体合金表面主要生成NiO;普通涂层表面主要生成Cr₂O₃,而且涂层内部出现内氧化和内硫化现象;复合涂层表面主要生成Al₂O₃,外层出现程度较轻的内氧化,涂层表层Al含量仍然较高,维持表面Al₂O₃膜的形成和修复.低温（700℃）热腐蚀条件下,基体合金表面主要生成NiO;普通涂层表面主要生成Cr₂O₃,涂层内部出现严重的内氧化;复合涂层表面也出现了内氧化,高Cr的内层未受腐蚀,有助于提高涂层的抗腐蚀性能.

HOT CORROSION BEHAVIOR OF A(NiCoCrAlYSiB+AlSiY) COMPOSITE COATING

Two kinds of the coatings,the conventional NiCoCrAlYSiB coating and the composite coating（NiCoCrAlYSiB+AlSiY）,were prepared using arc ion plating（AIP） on the Ni base single crystal superalloy substrate.Comparative studies of the hot corrosion behaviors of the substrate and two different coatings in Na₂SO₄ + K₂SO₄ and Na₂SO₄ + NaCl at 900 and 700°C were investigated. The results showed that,during the hot corrosion at 900°C,NiO was formed on the surface of the substrate while Cr₂O₃ was formed on the surface of the conventional coating with the formation of internal oxidation and sulfidation,and Al₂O₃ was formed on the surface of the composite coating. Slighter internal oxidation appeared in the outer layer of the composite coating.The composite coating contained sufficient Al reservoirs to supply the formation and repair of Al₂O₃.During the hot corrosion at 700℃,NiO was formed on the surface of the substrate and Cr₂O₃ was formed on the surface of the conventional coating with severe internal oxidation,while internal oxidation appeared in the outer layer of the composite coating.The Cr-enriched inner layer did not suffer from corrosion damage, which can improve the corrosion resistance of the composite coating.