H_2S溶液中316L不锈钢TIG焊接头的腐蚀性能  

Corrosion behavior of TIG welded joints of 316L stainless steel in H_2S solutions

作　　者：卢向雨[1] 冯兴国[2] 芦笙[1] 王泽鑫[1] 郑传波[1] 

机构地区：[1]江苏科技大学材料科学与工程学院,镇江212003 [2]河海大学港口海岸与近海工程学院,南京210098

出　　处：《焊接学报》2017年第5期69-73,共5页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51601074);高性能土木工程材料国家重点实验室开放基金资助项目(2015CEM006)

摘　　要：文中通过极化曲线、交流阻抗、Mott-Schottky曲线、浸泡腐蚀试验等方法对316L奥氏体不锈钢TIG焊接头各区域在不同浓度H_2S溶液中的耐蚀性能进行了研究.极化曲线及交流阻抗结果表明,随着溶液中H_2S浓度的升高,焊接接头各区域的耐蚀性明显降低.另一方面对于相同浓度的H_2S溶液,316L基体的耐蚀性最好,其次是热影响区,焊缝区的耐蚀性最差.Mott-Schottky曲线结果表明,焊接接头在H_2S溶液中的表面钝化膜形成p-n结结构,掺杂浓度高达10^(22)cm^(-3),且掺杂浓度随H_2S浓度升高而增大,致使钝化膜防护性能降低.316 L stainless steel welded joints was prepared by tungsten-arc inert gas( TIG) welding. The corrosion behavior of the TIG welded joints of 316 L stainless steel in different concentrations of H_2S solutions are studied by polarization curves,electrochemical impedance spectroscopy( EIS),MottSchottky plots,and immersion corrosion experiments. Polarization curves and EIS results show that the corrosion current densities of the joints significantly increased as the concentration of H_2S solutions increasing, while the corrosion potential decreased. Additionally,for the samples in the same concentration of H_2S solutions,the 316 L base material shows the lowest corrosion current densities,next is the heat-effected zone,the welded zone presents the highest corrosion current densities. Mott-Schottky plots show that the passive films appear a p-n heterojunction,and the donor and acceptor densities reach 1 022 cm^(-3),showing a highly defective character of the passive film. The donor and acceptor densities increase with increasing H_2S concentrations.The decreased passivity and the increased doping density affect the protectiveness of the passive film toward corrosion.

关 键 词：不锈钢 钨极惰性气体保护焊 硫化氢溶液 腐蚀 

分 类 号：TG444.4[金属学及工艺—焊接]