5052與6061鋁合金在鹽酸中腐蝕行為之比較

Comparison of the Corrosion Behavior of AA5052 and AA6061 in HCl Solutions

5052與6061鋁合金為目前消費性電子產品構裝常用之材料，其表面處理技術日益重要。本研究以電化學方法來研究、比較5052與6061鋁合金於鹽酸水溶液中腐蝕行為，並添加硫酸至腐蝕液中來探討其影響。電化學研究結果顯示：5052比6061鋁合金的腐蝕電位低，但腐蝕速率較高。其原因在於5052鋁合金中高活性的鎂含量較高，鎂成分的腐蝕較高，因而加速鋁合金的腐蝕。在交流電蝕研究中，5052鋁合金因均勻腐蝕嚴重，孔蝕則較不明顯，其表面累積有大量的深色腐蝕生成物。6061鋁合金的腐蝕較不嚴重，但孔蝕行為較為明顯。若添加硫酸將抑制鋁合金的均勻腐蝕但會加重孔蝕現象。

Aluminum alloys (AAs) 5052 and 6061 are materials widely used for packaging in the electronics industry. Surface treatments involving electrochemical techniques such as direct current and alternating current etching in acid solutions become more important nowadays. The corrosion behavior of AA5052 and AA6061 in HCl solutions was of interest and compared in this work. In addition, sulfuric acid was added in the foregoing solution to explore its effect on the corrosion of these two alloys. DC electrochemical measurements demonstrated the corrosion potential of AA5052 was lower than that of AA6061, and the corrosion current density of AA5052 was greater than that of AA6061. An examination on the corrosion morphology indicated AA5052 suffered from more severe corrosion than AA6061. The worse resistance of AA5052 to corrosion was ascribed to a higher content of Mg that is relatively active and easy to corrode. After an AC etching process, AA5052 revealed severe corrosion and pits were observed on the surface. Furthermopre, darkish corrosion products almost covered the entire surface. In comparison, AA6061 displayed only slight corrosion with numerous small pits distributing more uniformly on the surface. The addition of sulfuric acid in the HCl solution led to less severe uniform corrosion but enhanced pitting corrosion on these alloys.