中文摘要：

为了研究高温防护涂层对高温合金热腐蚀性能的影响，在一种镍基高温合金表面制备了NiCr-CrAl、Co—Al、Al-Si和Al—Ti四种改性的铝化物涂层，对比研究了4种涂层的组织结构和在900℃下的涂盐（25wt．％NaCl＋75wt．％Na2SO4）热腐蚀行为。结果表明：除NiCr-CrAl涂层外，其他三种涂层腐蚀声物中均含具有良好抗热腐蚀性能的Cr2O3、α-Al2O3和NiCr2O4氧化物。在900℃热腐蚀100h后，四种涂层表面呈现出不同的形貌。NiCr-CrAl涂层表面腐蚀产物明显不连续，存在局部的情蚀空洞；Co—Al涂层相对比较连续、致密，但有明显的裂纹，会引起涂层的退化乃至失效；Al-Si涂层出现剥落、空洞、裂纹及明显的内氧化；Ti-Al涂层剖面腐蚀产物不仅连续，而且非常致密，表现出最优异的抗热腐蚀性能。

英文摘要：

In order to study hot corrosion behaviors of the high temperature protective coatings on the superalloy, four modified aluminide coatings （NiCr-CrAI coating, Co-AI coating, AI-Si coating and Al-Ti coating） were prepared on the surface of a Ni-based superalloy. The microstructures and the hot corrosion behaviors in the salt of 25 wt. % NaCI ＋ 75 wt. % Na2SO4 at 900 ℃ were investigated. The results show that a large amount of mixed oxides include Cr2O3, α-Al2O3 and NiCr2O4 spinel have been formed on the surface of four coatings except for the NiCr-CrAI coating. The oxides can enhance the hot corrosion resistance of the coatings. Different morphologies appeared on the surface of the four coatings after corrosion for 100 h at 900 ℃. Obviously, discontinuous corrosion products and localized scaling zones occurred on the surface of the NiCr-CrAI coating. The Co-Al coatings were continuous and dense relatively after hot corrosion. However, obvious crack appeared on the surface, which can lead to great degradation and even failure of the coating. As for the Al-Si coating, not only the cracks and spalling arose on the surface, but also the internal oxidation were found in the substrate. The Ti - Al coating were continuously compact and adhered tightly to the substrate after corrosion. Obviously, the Ti-Al coating provided much better protection to the alloy than the other three coatings in this kind of mixed salt.