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痕量Cl-和Cu2+對(duì)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(zhàn)棟棟來(lái)源：中國(guó)腐蝕與防護(hù)學(xué)報(bào) 分享至：

摘要

針對(duì)3A21鋁合金在乙二醇冷卻液中的腐蝕問(wèn)題，采用浸泡實(shí)驗(yàn)和表面分析技術(shù)系統(tǒng)研究了痕量Cl-和Cu2+對(duì)3A21鋁合金在50 ℃乙二醇-水冷卻液中腐蝕行為的影響。結(jié)果表明，Cl-引發(fā)了鋁合金的點(diǎn)腐蝕，隨著Cl-濃度增大，鋁合金點(diǎn)蝕敏感性增大。Cu2+促進(jìn)鋁合金鈍化膜的破裂，并與Al發(fā)生置換反應(yīng)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(shí)，鈍化膜破裂和電偶作用導(dǎo)致鋁合金腐蝕加劇。

關(guān)鍵詞： 3A21鋁合金 ; 乙二醇 ; 痕量離子 ; 點(diǎn)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