中文摘要：

以含有较多较难去除的含铜金属间化合物黑色颗粒的铝合金2024-T3为研究对象，通过金相观察，开发了一种用于碱蚀后铝合金表面脱氧化物／出光的浓一稀两阶段处理技术。室温下先用含有5．0g／LNaHF2和100g／LFe2（SO4）3的30％（质量分数）硝酸溶液处理7min，然后用含有0．5g／LNaHF，的1％（质量分数）硝酸溶液处理4min，可有效去除碱洗后铝合金表面的黑色氧化物，形成无污染的氧化铝薄层。该工艺简单、快速、成本低，为后续转化反应的顺利进行奠定了基础。

英文摘要：

An Al alloy 2024-T3 with high concentration of hard-to-clean Cu-containing intermetallic particles was studied and a two-step technology using concentrated and diluted HNO3 solutions successively for oxide-removing/desmutting of alkaline-etched Al alloy was developed based on metallo- graphic analysis. Treating with 30% （mass fraction） HNO3 ＋ 5.0 g/L NaHF2 ＋ 100 g/L Fe2（SO4）3 solution at room texture for 7 min and subsequently with 1% （mass fraction） HNO3 ＋ 0.5 g/L NaHF： solution for 4 min can effectively remove contaminants on Al alloy surface after alkaline cleaning, resulting in a thin Al oxide layer without contaminants. The method is simple, fast and cost-effective. The treated surface is ready for the subsequent conversion reaction.