中文摘要：

采用超音速火焰喷涂在20#钢表面制备了Inconel 625/NiCr合金涂层,研究了涂层表面涂覆NaCl＋Na_2SO_4盐膜在700和750℃模拟烟气环境中的腐蚀行为。采用XRD,SEM/EDS对喷涂层以及高温腐蚀产物成分、形貌进行分析。结果表明：采用超音速火焰喷涂的625/NiCr涂层结构致密,孔隙率低,涂层中夹杂有金属氧化物;腐蚀动力学表明涂层在700和750℃先增重后失重,腐蚀产物有剥落;涂层试样的腐蚀层具有双层结构,外层富Ni而内层富Cr和S,在涂层/基体界面存在少量Cl,长期氧化过程中基体中Fe向涂层扩散。

英文摘要：

Inconel 625/NiCr coating was prepared on 20# steel substrate by high velocity oxygen fuel spray deposition. Hot corrosion behavior of the Inconel 625/NiCr coated steel beneath a film of mixed salts NaCl＋Na_2SO_4was investigated in simulated flue gas at 700 and 750 ℃ respectively.The microstructure and composition of the spray coating and corrosion products were characterized by scanning electron microscope/energy dispersive spectroscope and X-ray diffraction. The results showed that Inconel 625/NiCr coating prepared by HVOF was dense with low porosity, some oxides were observed in the coating. The samples experienced mass gain at the beginning corrosion stage and subsequently mass loss at 700 and 750 ℃. Spallation of corrosion products on the sample surface was detected. The scale of corrosion products had duplex microstructure, the outer layer was rich in Ni, and the inner layer was rich in Cr and S. A small amount of Cl was detected at the interface of coating and substrate. Fe would diffuse outward from substrate after long time corrosion.