退火处理对冷喷涂304SS涂层组织与耐蚀性能的影响

Influence of annealing treatment on microstructure and corrosion behaviour of cold sprayed 304 stainless steel coatings

采用冷气动力喷涂技术在低碳钢表面制备了304不锈钢涂层,并分别进行300、600、800和950℃保温1 h的退火热处理,研究了不同退火温度对涂层组织和耐蚀性能的影响。结果表明:冷喷涂涂层由大量变形粒子搭接构成,粒子间界面清晰可见。950℃退火处理后,涂层组织由等轴晶构成,大量粒子间界面消失。电化学测试结果表明涂层的腐蚀速率随退火温度升高而降低,涂层在950℃退火条件下达到最低腐蚀速率0.145 mm/y。

304 stainless steel coating was prepared on a low carbon steel by cold gas dynamic spray technology,and then was annealed at 300 ℃,600 ℃,800 ℃ and 950 ℃,respectively.The influence of heat treatment temperature on the microstructure and property of the 304SS coating was investigated by means of SEM,XRD,and potentiodynamic polarization tests.The results show that cold sprayed coating consists of flattened particles,and the interfaces are clearly observed between the deposited particles.After 950 ℃ annealing treatment at 950 ℃,the annealed coating presents equiaxed grain structures,and the particle interfaces almost disappear.Moreover,the potentiodynamic polarization test shows that the corrosion rate gradually decreases with increasing annealing temperature,and the lowest corrosion rate of 0.145 mm/y is obtained for the deposited coating annealed at 950 ℃.