中文摘要：

目的提高2024-T3铝合金在中性Na Cl溶液中的耐小孔腐蚀性能。方法采用动电位极化曲线测试、扫描电镜（SEM）观察并结合X射线光电子能谱（XPS）等方法,研究2024-T3铝合金在含不同浓度Na2Sn O3的0.1 mol/L Na Cl溶液中的电化学腐蚀行为,分析Na2Sn O3及其浓度对2024-T3铝合金小孔腐蚀和均匀腐蚀的作用。结果电化学测试结果显示,添加一定量（0.05~0.4 g/L）的Na2Sn O3可以使溶液的p H值升高（可从6.6上升至10.1）,促进铝合金表面发生钝化,使铝合金孔蚀电位Eb和自腐蚀电位Ecorr的差值增大（最大可达到600 m V）,因此降低了铝合金的孔蚀敏感性,提高了其耐小孔腐蚀的能力。但是Na2Sn O3质量浓度较大（0.2、0.4 g/L）时,会促进2024-T3铝合金的均匀腐蚀。SEM和XPS结果显示,小孔及其附近区域Cu含量较多,并有大量的Sn O2颗粒沉积。结论少量（0.05、0.1 g/L）的Na2Sn O3对2024-T3铝合金的小孔腐蚀和均匀腐蚀均具有较好的抑制效果。Na2Sn O3对2024-T3铝合金的缓蚀作用可能源于其水解产生的Sn O2优先在铝合金表面的金属间颗粒（S相）周围发生沉淀,从而屏蔽了铝合金表面的活性点。

英文摘要：

Objective To improve the pitting corrosion resistance of 2024-T3 aluminum alloy in neutral sodium chloride solution. Methods In this paper,potentiodynamic polarization curves,scanning electron microscopy（ SEM） combined with X-ray photoelectron spectroscopy（ XPS） methods were used to study the electrochemical corrosion behavior of 2024-T3 aluminum alloy in0. 1 mol / L Na Cl solution containing different contents of sodium stannate（ Na2 Sn O3）. The influence of sodium stannate and its concentration on the pitting corrosion and uniform corrosion of 2024-T3 aluminum alloy was analyzed. Results The electrochemical test results showed that a certain amount（ 0. 05 ~ 0. 4 g / L） of sodium stannate addition could increase the p H value of solution（ from 6. 6 to 10. 1）,promote the passivation of aluminum alloy,and increase the gap between pitting corrosion potential（ Eb） and free corrosion potential（ Ecorr）（ up to the maximum of 600 m V）. So sodium stannate could reduce the susceptibility of 2024-T3 aluminum alloy to pitting corrosion and improve the pitting corrosion resistance. However,further increased concentrations of sodium stannate（ 0. 2 g / L and 0. 4 g / L） accelerated the uniform corrosion of aluminum alloy. SEM and XPS results demonstrated the presence of high content of Cu element around the pits and a lot of Sn O2 particles deposited on the pits and their peripheral regions.Conclusion A small amount（ 0. 05 g / L and 0. 1 g / L） of Na2 Sn O3had good inhibition effect on both pitting corrosion and uniform corrosion. The inhibition effect of sodium stannate on 2024-T3 aluminum alloy might be due to the preferential deposition of hydrolysate Sn O2 on the intermetallic particles（ S phase）,so as to block the active sites on the aluminum alloy surface.