锅炉受热面NiCr涂层抗高温热腐蚀机制与性能的研究

针对电站锅炉受热面高温腐蚀的影响,通过采用电弧喷涂工艺,研究了Q235钢板表面电弧喷涂PS45、FeCrAl、4Cr13合金涂层后在高温条件下的热腐蚀机制与性能.热腐蚀动力学试验和分析结果显示,在700℃下腐蚀77 h、Na2SO4+K2SO4盐膜量为3~4 mg/cm2的试验条件下,测试得到的PS45、FeCrAl、4Cr13合金涂层的热腐蚀速度分别为υ=0.38t-0.59、υ=1.35t-0.12和υ=1.79t-0.23.涂层表面的成分和组织分析结果表明,Q235钢板表面的PS45涂层之所以表现出比FeCrAl、4Cr13涂层更高的抗热腐蚀(Na2SO4/K2SO4)性能,其原因在于PS45镍基合金中含有最多的Cr,涂层表面的Cr2O3膜层具有较高的连续性、致密性和稳定性.

Study on high temperature corrosion mechanism and property of Ni-Cr coatings on boiler heating surface

According to the high temperature corrosion influence on the boiler heating surface in power plant,using arc spraying process,the high temperature corrosion mechanism and property of Q235 steel with arc sprayed PS45,FeCrAl and 4Cr13 alloy coating are studied.In condition of 77 h corrosion at 700 ℃ and 3~4 mg/cm2 Na2SO4+K2SO4 salt film amount,the results of kinetic thermal corrosion test and analysis show that the velocity of thermal corrosion of PS45,FeCrAl and 4Cr13 alloy coatings is v=0.38t-0.59,v=1.35t-0.12 and v=1.79t-0.23 respectively.The composition and structure of coatings are analyzed,the results show that PS45 alloy coatings is better than FeCrAl and 4Cr13 in high temperature corrosion(Na2SO4+K2SO4) on Q235 steel surface,that’s because the content of Cr in PS45 alloy is the most and the Cr2O3 film on coatings is of fairly good continuity,compactness and stability.