| 摘要 |
A raw aluminum foil for use to prepare electrolytic condenser electrodes has an aluminum purity of 99.9 % or higher and contains 50 - 500 ppm of Mg. A method of etching the raw foil to prepare the electrodes consists of a primary etching step and a secondary etching step, and the primary etching is conducted in an aqueous bath containing 3 - 10 % by weight of HCl and 10 - 40 % by weight of H2SO4, at 70 - 90 DEG C and with a current density of 10 - 40 A/dm<2>. The secondary etching is conducted electrolytically or chemically in a further bath containing 3 - 10 % by weight of HCl, with or without 1 % or less of H2C2O4 added to the further bath, at a bath temperature of 70 - 95 DEG C and with a current density of 0 - 10 A/dm<2>. |
