紫铜在海洋大气环境中的腐蚀研究

Corrosion Behaviors of Copper in Marine Atmospheric Environments

目的通过设计海洋大气环境模拟系统,研究紫铜在Na Cl沉积、温度、相对湿度和紫外光照等因素协同作用下的腐蚀机制.方法利用扫描电子显微镜(SEM)和X-射线衍射仪(XRD)分别分析样品Na Cl沉积、温度为(25±1)℃,相对湿度为85%条件下紫铜的表面形貌和腐蚀产物结构特征;采用电化学极化曲线分析紫铜经不同波长紫外光照射后自腐蚀电位和电流密度的变化,进而来分析紫外光照对紫铜腐蚀的影响机制.结果腐蚀产物主要有Cu(OH)Cl和Cu_2(OH)_3Cl;随着腐蚀时间的延长,腐蚀产物种类不变,只是数量不断增多,样品表面出现孔洞和微裂纹,为腐蚀反应的进行提供了更多的通道,在这些表面缺陷上方产生新的产物;经波长为185 nm的紫外线辐照后样品的自腐蚀电位最高,电流密度最小;波长为254 nm的紫外线辐照后的样品自腐蚀电位最低,电流密度最大.紫铜经波长为185 nm紫外线辐照产生的腐蚀产物最致密.结论笔者成功模拟了紫铜在海洋大气环境下的腐蚀行为,得出三种波长紫外线对紫铜的影响机制,提出了不同环境下紫铜的腐蚀方式.

The system simulating atmospheric corrosion was used to study the interaction mechanism of Na Cl and UV on corrosion of copper in the marine atmospheres with 85% relative humidity（RH）.All experiments were performed at room temperature（25±1） ℃.Morphology,structures and electrochemical performance of the corrosion products were investigated by Scanning Electron Microscope（SEM）,X-ray diffraction（XRD） and the electrochemical method.The results reveal that the corrosion products are mainly consisted of Cu（OH） Cl and Cu2（OH）3Cl.The kinds of corrosion products of Cu are the same in all these atmospheres,and the quantities of the corrosionproducts increase with the reaction time.Void and micro-cracks appear during the electrochemical corrosion process.The new products growabove the defects,which indict that micro-cracks provide channels for ion transport.The electrochemical polarization curve show s that the corrosion potentials and current densities of copper samples illuminated by UV light with the different wavelengths are different.The corrosion potential of sample illuminated by the light with the wavelength of 185 nm is the highest,and that with the wavelength of 254 nm is the lowest.Simultaneously,the corrosion current density of sample illuminated by the light with the wavelength of 185 nm is the minimum,and that with the wavelength of 185 nm is the maximum.The simulative system is an effective way to model the corrosion behavior and reveal the corrosion mechanism of copper in marine atmospheric environment,the research conclusions the mechanism of the effect of sodium chl the corrosion methods of copper under different environments.