Abstract The influence of 2024 aluminium alloy microstructure on the protective properties of trivalent chromium process (TCP) coatings was studied: samples aged at 190 °C were analysed by comparison to a T3 state. The surface Cu coverage after deoxidation was higher for long-aged samples because nanometer scale Cu-rich precipitates formed during ageing behaved as distinct electrochemical entities and contributed to the formation of copper deposits. The growth mechanisms and kinetics of TCP coatings were directly related to the surface Cu coverage: thicker but more defective TCP coatings formed on long-aged samples leading to the lowest anti-corrosion properties.

中文翻译：

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显微组织对涂有三价铬转化层的2024铝合金腐蚀行为的影响

摘要 研究了 2024 铝合金显微组织对三价铬工艺 (TCP) 涂层保护性能的影响：通过与 T3 状态的比较分析了 190 °C 时效的样品。对于长时间老化的样品，脱氧后的表面铜覆盖率更高，因为老化过程中形成的纳米级富铜沉淀表现为不同的电化学实体，并有助于铜沉积物的形成。TCP 涂层的生长机制和动力学与表面铜覆盖率直接相关：在长期老化的样品上形成更厚但缺陷更多的 TCP 涂层，导致最低的防腐性能。