环保彩锌镀层在NaCl介质中的腐蚀行为研究  

Corrosion Behavior of Chromium Color Passivating Coating in NaCl Solution

作　　者：陈亮[1] 王鹤云[1] 武文鑫 丁毅[1] 马立群[1] 

机构地区：[1]南京工业大学,江苏南京210009 [2]无锡鹰贝电化学有限公司,江苏无锡214416

出　　处：《铸造技术》2012年第10期1171-1173,共3页Foundry Technology

摘　　要：采用Tafel直线外推法、加速腐蚀试验,研究了环保彩锌镀层在NaCl溶液中的腐蚀行为,利用扫描电镜和能谱分析表征彩锌镀层的腐蚀形貌和腐蚀产物。结果表明:随着NaCl浓度的升高,彩锌镀层腐蚀电流密度增大;在-1.2^-0.7 V区域内,彩锌镀层发生阳极钝化;镀锌层的3价铬钝化膜可阻碍Cl-腐蚀,在随后的加速腐蚀试验所产生的腐蚀产物可再次阻碍Cl-腐蚀;由于Cl-存在强吸附和强穿透性,使得钝化膜产生破裂并使Zn腐蚀;随着时间的增加,在Cl-的进一步作用下,钝化膜被破坏殆尽,甚至有些已经侵入基体形成Zn-Fe原电池加速了Zn的腐蚀。The corrosion behavior of chromium（Ⅲ） color passivating coating in NaCl solution was studied by Tafel linear extrapolation and accelerated corrosion test.Morphologies and corrosion products after corrosion were characterized by SEM and EDS.The results show that the corrosion current density of chromium（Ⅲ） color passivating coating becomes larger with the increase of the concentration of NaCl solution.The coating is passivated in the range from-1.2 V to-0.7 V.The corrosion of Cl-is firstly hindered by chromium（Ⅲ） color passivating film,and secondly hindered by corroded products in the accelerated corrosion test.The intense absorption and penetration of Cl-makes passive film crack and Zn be corroded.With the increase of time,passive film is destroyed and even the corrosion of Zn is accelerated resulting from forming Zn-Fe galvanic cells.

关 键 词：镀锌 彩锌钝化 封闭 腐蚀 

分 类 号：TG174.44[金属学及工艺—金属表面处理]