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痕量Cl-和Cu2+對3A21鋁合金在乙二醇冷卻液中腐蝕行為的影響

2021-05-19 14:16:37 作者：戰棟棟來源：中國腐蝕與防護學報分享至：

摘要

針對3A21鋁合金在乙二醇冷卻液中的腐蝕問題，采用浸泡實驗和表面分析技術系統研究了痕量Cl-和Cu2+對3A21鋁合金在50 ℃乙二醇-水冷卻液中腐蝕行為的影響。結果表明，Cl-引發了鋁合金的點腐蝕，隨著Cl-濃度增大，鋁合金點蝕敏感性增大。Cu2+促進鋁合金鈍化膜的破裂，并與Al發生置換反應沉積在鋁合金表面，電偶作用加速了鋁合金的腐蝕。Cl-和Cu2+共存時，鈍化膜破裂和電偶作用導致鋁合金腐蝕加劇。

關鍵詞： 3A21鋁合金 ; 乙二醇 ; 痕量離子 ; 點蝕

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