关键词: 电解加工, 铝合金, 钝化, 电流效率, 表面形貌

Abstract: 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.

Key words: electrochemical machining, aluminum alloy, passivation, current efficiency, topography