激光熔覆316L不锈钢涂层的结构与腐蚀性能

使用激光多道搭接法在45#钢基底表面熔覆316L不锈钢粉末涂层,对比研究了激光涂层和对应商用棒材的微观结构及其分别在2mol NaCl,1mol FeCl3和0.5mol HCl溶液中的阳极极化腐蚀行为。结果表明,单层激光熔覆粉末涂层受基底钢材稀释的影响,涂层最终的微观结构由马氏体和极少量的奥氏体组成。激光熔覆粉末涂层和商用棒材在上述溶液中表现出相似的极化行为,阳极极化和阴极极化的超电位都遵循Tafel关系,表现出很好的钝化性能和点蚀抗力。与商用棒材相比,涂层材料的自腐蚀电流大、自腐蚀电位低、极化电阻小、抗腐蚀能力略有下降。

icrostructure and corrosion performance of laserclad 316L stainless steel coating

L stainless steel powders were clad onto AISI 1045 steel substrate using laser multi-track overlapping process.The microstructure and anodic polarization corrosion behavior in 2mol NaCl,1mol FeCl 3 and 0.5mol HCl aqueous solutions of the clad layer and its commercial counterpart bulk 316L stainless steel were comparatively investigated.The chemical composition of the clad layer resulted from dilution from the substrate is quite different from that of the original 316L stainless steel powders,the final microstructure of the clad layer comprised predominant martensite and very small amount of residual austenite.The anodic polarization behavior of the clad layer was similar to that of its commercial counterpart bulk in the aqueous solutions mentioned above.There exists Tafel relationship between the superpotential of anodic and cathodic polarization and current for both the clad layer and the bulk.The clad layer displays good passive performance and pitting corrosion resistance.Compared with the bulk,however,the clad layer has larger self-corrosive current density,lower potential and smaller polarization resistance,and its corrosion resistance slightly degrades.