目的 研究超音速喷涂不同Ni、Cr含量涂层在模拟烟气中的热腐蚀行为，比较涂层的耐蚀性能。探讨涂层在模拟环境中的腐蚀机理。方法 采用超音速火焰喷涂技术，在20钢表面制备不同Ni、Cr含量的合金涂层。涂层试样涂覆75%Na2SO4+25%NaCl混合盐膜，在750 ℃含0.15%（体积分数）SO2模拟烟气中进行腐蚀测试，获得腐蚀动力学规律。采用XRD、SEM、EDS对涂层以及高温腐蚀产物的成分、结构、形貌进行分析。结果 采用超音速火焰喷涂制备的涂层结构致密，平均孔隙率为0.84%，涂层中有少量金属氧化物。腐蚀过程中，涂层试样先增重后失重，腐蚀产物为NiO、NiCr2O4、FeCr2O4和(Fe,Cr)2O3。腐蚀产物具有双层结构，外层富Ni，内层富Cr。结论 在测试条件下，Ni的质量分数为64%，Cr的质量分数为23%时，涂层具有较好的耐蚀性。

The work aims to study hot corrosion behavior of Ni-base alloy coatings with various Ni and Cr content in simulated fuel gas prepared by HOVF, and compare corrosion resistance of the coatings. Corrosion mechanism of Ni-base alloy coating was discussed in brief. Ni-base alloy coatings with various Ni and Cr content were prepared on 20# steel substrate by high velocity oxyfuel spraying (HOVF). Hot corrosion tests were performed to the samples coated with 75%Na2SO4+25%NaCl mixed salt film in 0.15% SO2 simulated flue gas at 750 ℃ to obtain corrosion dynamic law was obtained. Composition, structure, morphology of the coatings and high temperature corrosion products were investigated by using XRD, SEM and EDS. The Ni-base coatings prepared by HVOF were dense with porosity of 0.84%. A little oxides were detected in the coating as well. All samples were first subject to mass gain and then mass loss during corrosion. The corrosion products were NiO, NiCr2O4, FeCr2O4 and (Fe,Cr)2O3. The corrosion products had bilayer microstructure, Ni-enriched external layer and Cr-enriched internal layer. The coating with 64wt.% Ni and 23wt.% Cr exhibits good corrosion resistance in the test environment.