铝合金电解加工中的钝化行为及其对加工过程的影响

本文研究与分析了铝合金电解加工过程的钝化行为，探讨了加工电压、电流密度、加工间隙及电解液成分等因素对电解加工性能的影响. 研究表明，在试验温度（23 ± 1）^oC下，铝合金在NaNO₃和NaF复合电解液体系（钝化电解液）存在钝化现象，钝化降低了电解加工的电流效率，并使电流效率随电流密度发生较大变化. 同时，钝化也使间隙特征曲线负移. 而在相同浓度NaCl和NaF复合电解液体系（活化电解液）电解加工，可在很宽的电位范围内保持活性溶解. 在钝化电解液中，电解加工表面更加平整.

Passivation Behavior of Aluminum Alloy during Electrochemical Machining and Its Effects on the Machining Performance

The passivation behavior of aluminum alloy during electrochemical machining was investigated and discussed. The effects of processing voltage, current density, space of electrodes and electrolyte composition on electrochemical machining performance were explored. The results indicate that the electrochemical machining aluminum alloy in the composite electrolyte system containing NaNO₃ and NaF existed passivation phenomenon. Passivation action decreaseed the current efficiency and made it varied greatly with the current density. Also the passivation shifted the interspace characteristic curve of electrode notably to a negative direction. There was not passivation phenomenon in the composite electrolyte system containing the same concentrations of NaCl and NaF for the electrochemical machining of aluminum alloy. It kept active dissolution in a wide range of potential. More uniform machining surface could be obtained in passive electrolyte.