MgCl2对锌在干湿交替环境中腐蚀行为的影响

2021-05-06 16:38:56 作者：尹奇来源：材料研究学报分享至：

摘要

使用腐蚀失重、X射线衍射（XRD）、扫描电子显微镜与能谱（SEM-EDS）等手段研究了干湿交替环境中MgCl2对锌腐蚀行为的影响。结果表明，MgCl2对锌的腐蚀有显著的抑制作用；在沉积NaCl条件下锌表面的腐蚀产物为Zn5（OH）8Cl2·H2O、Zn4CO3（OH）6·H2O和Zn（OH）2，而在沉积MgCl2条件下锌表面的腐蚀产物只有Zn5（OH）8Cl2·H2O。在干湿交替环境中MgCl2对锌腐蚀行为的影响主要是Mg2+与氧还原反应产生的OH-结合使阴极区的pH值降低造成的。

关键词：材料失效与保护 ; 大气腐蚀机制 ; 室内模拟加速腐蚀实验 ; MgCl2 ; 锌

Abstract

The effect of MgCl2- and NaCl-deposit on simulated atmospheric corrosion of Zn was comparatively investigated via wet-dry alternating corrosion test, as well as mass loss, X-ray diffraction （XRD）， scanning electron microscope equipped with energy dispersive spectrometer （SEM-EDS）。 The results show that the corrosion rate of Zn was significantly inhibited by the deposition of MgCl2; the corrosion products formed on Zn plate with NaCl deposit were Zn5（OH）8Cl2·H2O、Zn4CO3（OH）6·H2O and Zn（OH）2, while was only Zn5（OH）8Cl2·H2O for Zn plate with MgCl2 deposit. It was proposed that the corrosion may be caused by the decrease of pH, which was induced by the precipitation of Mg2+ ions and OH- ions, in the cathodic sites.

Keywords： materials failure and protection ; atmospheric corrosion mechanism ; laboratory simulated corrosion test ; MgCl2 ; zinc