痕量Cl-和Cu2+对3A21铝合金在乙二醇冷却液中腐蚀行为的影响

2021-05-19 14:16:37 作者：战栋栋来源：中国腐蚀与防护学报分享至：

摘要

针对3A21铝合金在乙二醇冷却液中的腐蚀问题，采用浸泡实验和表面分析技术系统研究了痕量Cl-和Cu2+对3A21铝合金在50 ℃乙二醇-水冷却液中腐蚀行为的影响。结果表明，Cl-引发了铝合金的点腐蚀，随着Cl-浓度增大，铝合金点蚀敏感性增大。Cu2+促进铝合金钝化膜的破裂，并与Al发生置换反应沉积在铝合金表面，电偶作用加速了铝合金的腐蚀。Cl-和Cu2+共存时，钝化膜破裂和电偶作用导致铝合金腐蚀加剧。

关键词： 3A21铝合金 ; 乙二醇 ; 痕量离子 ; 点蚀

Abstract

In view of the corrosion of 3A21 Al-alloy in glycol coolant, this paper studied the influence of trace amounts of Cl- and Cu2+ ions on the corrosion behavior of 3A21 Al-alloy in ethylene glycol-water coolant at 50 ℃ by immersion experiments and surface analysis technology. The results indicated that Cl- ions resulted in pitting corrosion of the alloy, and the pitting corrosion susceptibility increased with the increase of the concentration of Cl-. Cu2+ ions could promote the breakdown of the passive film, and react with Al resulting in a deposition of metallic Cu on the Al-alloy surface, which in turn accelerated the corrosion of Al-alloy owing to the galvanic effect. 3A21 Al-alloy took place serious corrosion owing to the overlapping effect of the breakdown of the passive film and the galvanic effect in the case of co-existence of Cl- and Cu2+.

Keywords： 3A21 Al-alloy ; ethylene glycol ; trace ions ; pitting