耐蚀性铝合金酒石酸-硫酸阳极氧化工艺研究

Study on anticorrosive tartaric-sulfuric acid anodization for aluminum alloy

研究了铝合金的酒石酸-硫酸阳极氧化工艺,考察了氧化膜的厚度、耐中性盐雾腐蚀性能和漆膜附着力。结果表明,铝合金材料的表面状态对酒石酸-硫酸阳极氧化表面形貌有重要影响,氧化膜的厚度随阳极氧化时电流密度的增大而变大。在同样条件下,7175-T7351铝合金的氧化膜厚度比2024-T3铝合金的更大。阳极氧化后沸水封闭40 min以上可有效提高铝合金的耐蚀性。酒石酸-硫酸阳极氧化槽液中酒石酸的质量浓度低于74g/L时,2024-T3铝合金阳极氧化试片的耐蚀性降低。未封闭的酒石酸-硫酸阳极氧化膜与水性底漆有良好的结合力。

The tartaric-sulfuric acid(TSA)anodizing process for aluminum alloys was studied.The thickness,natural salt spray corrosion resistance,and paint adhesion of the anodic oxide films were tested.The results showed that the morphology of the anodic oxide film surface was greatly affected by the surface state of aluminum alloy substrate.The thickness of anodic oxide film was increased with the increasing of current density during anodizing.The anodic oxide film on 7175-T7351 aluminum alloy was thicker than that on 2024-T3 aluminum alloy under the same anodizing conditions.The corrosion resistance of the anodic oxide film was improved effectively by hot water sealing for at least 40 min.The corrosion resistance of the anodized 2024-T3 aluminum alloy was degraded when the mass concentration of tartaric acid was lower than 74 g/L in the electrolyte.The unsealed anodic oxide film had good adhesion to a waterborne primer coating.