300M超高强度钢在模拟海洋环境中的腐蚀行为研究  

Corrosion Behavior of 300M Ultra High Strength Steel in Simulated Marine Environment

作　　者：李晗 刘元海 赵连红 崔中雨 LI Han;LIU Yuanhai;ZHAO Lianhong;CUI Zhongyu(School of Materials Science and Engineering,Ocean University of China,Qingdao 266100,China;China Special Vehicle Research Institute,Jingmen 448004,China)

机构地区：[1]中国海洋大学材料科学与工程学院,青岛266100 [2]中国特种飞行器研究所,荆门448004

出　　处：《中国腐蚀与防护学报》2023年第1期87-94,共8页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金(51601182)。

摘　　要：采用模拟海水全浸区的浸泡实验和模拟海洋大气区的中性盐雾实验,结合宏观和微观形貌、三维形貌、腐蚀产物分析以及电化学阻抗谱(EIS)和动电位极化曲线(PDP)测试,研究了起落架用300M超高强度钢在模拟海洋环境中的腐蚀行为以及pH对其电化学行为的影响。结果表明:300M超高强度钢对pH的变化敏感,随着pH的降低,开路电位正移;阳极过程始终由活性溶解控制,阴极过程由氧还原为主转变为析氢反应为主;容抗弧半径下降,电荷转移电阻下降,腐蚀电流密度上升,腐蚀加快。失重法得出的腐蚀速率说明在盐雾环境中比人工海水环境中的腐蚀更为严重;两种环境中的腐蚀产物均主要由α-FeOOH、γ-FeOOH、α-Fe_(2)O_(3)和Fe_(3)O_(4)组成;腐蚀呈现均匀腐蚀的特征。由于氧浓度和Cl-浓度的差异导致300M超高强度钢在两种环境中的腐蚀电化学和腐蚀产物沉积过程改变,从而腐蚀行为出现差异。盐雾环境中供氧充足,同时试样表面覆盖的薄液膜促进了腐蚀产物沉积使腐蚀更为严重。The corrosion performance of the 300M steel was assessed via artificial seawater immersion testing and neutral salt spray testing,aiming to simulate the operation environments,by means of electrochemical methods(i.e.OCP,EIS,PDP)and modern instruments(i.e.SEM+EDS,XRD,CLSM etc.).The results show that 300M ultra high strength steel is sensitive to the change of pH for artificial seawater.With the decrease of pH,the cathodic curve changes from oxygen reduction to hydrogen evolution process control,and the open circuit potential(OCP)moves positively,the charge transfer resistance decreases,and the corrosion current density increases.The fitting results of polarization curve and Nyquist diagram indicate that the decrease of pH leads to the acceleration of corrosion.The corrosion rate calculated by mass loss method shows that the corrosion in salt spray testing is more serious than that in artificial seawater immersion testing.However,in the above two cases the steel all presents characteristics of uniform corrosion.This was further proved by observation results of surface morphology and cross-sectional morphology of the tested steel.The corrosion products thickened with local spallation as the progress of corrosion process.The corrosion products was composed ofα-FeOOH,γ-FeOOH,α-Fe_(2)O_(3)and Fe_(3)O_(4),the more theα-FeOOH.The difference in corrosion behavior of the 300M steel by immersion testing and salt spray testing is determined by the corrosion electrochemical reaction process and the deposition process of corrosion products.During the salt spray testing,the steel surface covered by thin electrolyte film with adequate oxygen supply,which promotes the deposition of corrosion products,thus promoting the adsorption of Cl-,and ultimately accelerating the corrosion.

关 键 词：300M超高强度钢 人工海水 腐蚀产物 电化学行为 钢腐蚀 

分 类 号：TG172[金属学及工艺—金属表面处理]