| 摘要 |
A method of etching aluminum by applying an alternating electric current to aluminum which is in contact with an electrolyte containing hydrochloric acid, in which the alternating current has a symmetrical waveform wherein the current rises rapidly from zero to a maximum, then subsequently decreases rapidly in a first stage to an intermediate value which is about one-third to about one-half of the maximum, and thereafter decreases more slowly to zero in a second stage. Thereafter the current rises and falls in the opposite direction with the same waveform. The ratio of time of the second stage to time of the first stage of the waveform is in the range from 1 to 6. By this procedure higher capacitance values of the etched aluminum are obtained in comparison to prior procedures.
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