| 摘要 |
An electrolytic bath for coating articles of aluminum and its alloys consists essentially of an aqueous solution containing an alkali metal silicate, a peroxide, a water-soluble carboxylic group-containing organic acid and a water-soluble fluoride. A vanadium compound may also be included in the bath whenever the coated articles are intended to be used for decorative purposes. In the process, the aluminum article is immersed in the bath and a voltage shock is applied thereto by imposing a voltage potential between the aluminum metal serving as the anode and a cathode immersed in the bath. The voltage potential is quickly raised to about 300 volts within about 2 to about 10 seconds and thereafter, the voltage is increased gradually to about 450 volts within a few minutes until the desired coating thickness is formed. |
