KMnO_4对铝合金阳极的阻化研究

Inhibition of KMnO_4 to Al-alloy-anodes in NaCl solution

研究了含Ga、Sn的高活性铝合金阳极的电化学性能。发现这种铝合金阳极一旦活化 ,其表面膜被破坏 ,就会与水反应剧烈 ,造成大量析氢。而在中性电解液中添加的微量KMnO4 ,虽然未改变铝合金阳极溶解时析氢的“负差效应”规律 ,却对铝合金阳极析氢有明显抑制作用。在铝合金阳极表面还原生成一层含MnO2 和Al2 O3 的褐色阻化膜 ,这层膜阻碍了基体铝与中间价态的Al+(ad) 与水的直接反应 ,并且阻碍了金属铝微粒脱落 ,减少其在溶液中与水的反应。同时 ,由于表面膜能抑制非成流反应的进行 ,还降低了阳极极化。

The electrochemical performance of Al-alloy-anode with high active elements and Ga, Sn contents was investigated. When the Al-alloy-anode was activated, the passive oxide film was broken, the anode reacted rapidly with H 2O and released a vast amount of hydrogen. The hydrogen release was inhibited when trace KMnO 4 was added to the nutral solution, although the negative difference effect wasnt changed. The film with MnO 2 and Al 2O 3 on aluminum surface prevented the bare part of aluminum and the intermedia ion Al + ad reacting directly with H 2O, as well as the small pieces of aluminum splitting away from the electrode and corroding freely in the solution. And, the anodic polarization decreased for the film inhibited by reaction.