2507双相不锈钢在海水脱硫不同阶段的腐蚀钝化行为  

Corrosion and passivation behavior of 2507 duplex stainless steel at different stages of seawater desulfurization

作　　者：寇晓培 张钰柱 余翠兰 冯淼 田于财 KOU Xiao-pei;ZHANG Yu-zhu;YU Cui-lan;FENG Miao;TIAN Yu-cai(College of Intelligent Engineering,Chongqing College of Mobile Communication,Chongqing 401520,China)

机构地区：[1]重庆移通学院智能工程学院,重庆401520

出　　处：《材料热处理学报》2023年第7期115-126,共12页Transactions of Materials and Heat Treatment

基　　金：重庆市教委科学技术研究项目青年项目(KJQN202002402)。

摘　　要：通过开路电位、动电位极化法、恒电位极化法、电化学阻抗、Mott-Schottky曲线和腐蚀形貌观察法等研究了2507双相不锈钢在海水脱硫过程中不同阶段的腐蚀钝化行为。结果表明:在海水脱硫过程中,SO_(2)会转变为Na HSO_(3)、Na_(2)SO_(3)和Na_(2)SO_(4),导致2507双相不锈钢的耐腐蚀性能先下降后上升。2507双相不锈钢在不同人工海水中发生了选择性腐蚀,点蚀优先在α/γ相相界和α相区形核生长,点蚀孔从窄深型转变为宽深型。HSO_(3)-和SO_(3)^(2-)对实验钢的耐腐蚀性能具有损害作用,并且SO_(3)^(2-)的损害作用程度大于HSO_(3)^(-),SO_(4)^(2-)对耐腐蚀性能无影响。HSO_(3)^(-)和SO_(3)^(2-)会阻碍钝化膜生成过程并提高钝化膜掺杂浓度,导致钝化膜导电性提升和屏蔽性能下降。Corrosion and passivation behaviors of 2507 duplex stainless steel at different stages during seawater desulfurization were studied by means of open circuit potential,potentiodynamic polarization,potentiostatic polarization,electrochemical impedance,Mott-Schottky curve and corrosion morphology observation.The results show that SO_(2) will be transformed into NaHSO_(3),Na_(2)SO_(3) and Na_(2)SO_(4) in the process of seawater desulfurization,resulting in the fact that the corrosion resistance of the 2507 duplex stainless steel first decreases and then increases.The 2507 duplex stainless steel has undergone selective corrosion in different artificial seawater,the pitting corrosion preferentially nucleates and grows at the α/γ phase boundary and α phase zone,and the pitting hole changes from narrow deep type to wide deep type.HSO_(3)^(-) and SO_(3)^(2-) can damage the corrosion resistance of the experimental steel,the damage degree of SO_(3)^(2-) is greater than that of HSO_(3)^(-),and SO_(4)^(2-) has no effect on the corrosion resistance.HSO_(3)^(-) and SO_(3)^(2-) will hinder the formation process of the passive film and increase the doping concentration of the passive film,resulting in the improvement of the conductivity and the decrease of the shielding performance of the passive film.

关 键 词：2507双相不锈钢 海水脱硫 SO_(2) 钝化膜 腐蚀行为 钝化行为 

分 类 号：TG142.7[一般工业技术—材料科学与工程]