镀锌板常温三价铬黑色钝化膜的制备及其耐蚀性能  

Preparation at Room Temperature of Trivalent Chromium Black Passivation Coating on Galvanized Steel and Evaluation of Corrosion Resistance of the Coating

作　　者：刘伟振[1] 孙杰[1] 孙慧艳[2] 

机构地区：[1]沈阳理工大学环境与化学工程学院,辽宁沈阳110159 [2]沈阳黎明航空发动机(集团)有限责任公司热表处理厂,辽宁沈阳110043

出　　处：《材料保护》2015年第8期17-20,6-7,共4页Materials Protection

摘　　要：为了提高镀锌板的耐蚀性,以有机硫化物为发黑剂,研制了一种性能稳定的三价铬黑色钝化液,并用该钝化液在常温下对镀锌板进行钝化处理。通过扫描电镜(SEM)观察、醋酸铅点滴试验、Tafel极化曲线和交流阻抗谱测试等方法分析了钝化膜的外观形貌、元素组成及耐蚀性能。结果表明:钝化膜主要含有Zn,Cr,O等元素;钝化膜封闭后乌黑油亮,具有良好的装饰性能,且附着力合格;镀锌板经钝化后,耐醋酸铅点滴时间约为71 s,能有效地阻滞腐蚀的阳极过程,使自腐蚀电位由-1.283 V升高到-1.054 V,正移了近230 m V;自腐蚀电流密度由12.240μA/cm2减小到了2.866μA/cm2,显著提高了镀锌板的耐蚀性。A kind of trivalent chromium passivation solution with stable performance was prepared with the organic sulfide as blackening agent,and then was used for the passivating treatment of the galvanized steel at room temperature.The surface morphology and element composition of the passive films were analyzed by scanning electron microscopy and energy dispersive spectrometer.Moreover,the corrosion resistance of the passive films was investigated by lead acetate spot test,Tafel polarization and AC impedance.Results showed that the passive film was mainly composed of Zn,Cr and O elements.The passive film was black and shiny,showing good decorative property and good adhesion.Furthermore,the galvanized steel sheet after passivation treatment could endure lead acetate spot test for about 71 s and block effectively the anode process of the corrosion,with the positive shift of corrosion potential from-1.283 V to 1.054 V.Meanwhile,the corrosion current density reduced from 12.240 μA/cm^2 to 2.866μA/cm^2,indicating that the corrosion resistance of galvanized sheet was improved significantly by the passivation film.

关 键 词：黑色钝化 三价铬 镀锌板 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]