| 摘要 |
474,704. Electrolysis. WALES, F. A. Nov. 12, 1936, Nos. 30930 and 30931. Convention dates, Nov. 14, 1935 and Nov. 29, 1935. [Class 41] A protective coating is formed on aluminium or its alloys by utilizing the aluminium as an electrode in a bath containing about 13 per cent by weight of sulphuric acid, alternating current being supplied, first at 9-12À5 volts and then at higher voltages up to 24 at the end of the treatment. The coating formed, e.g. on pistons, may be impregnated with a lubricant, such as graphite dispersed in oil. The process may be effected by suspending the aluminium articles 33 from the bus-bars 32, the electrolyte being contained in a leadlined tank 14. The electrolyte is agitated by air supplied to pipes 21, and its temperature is controlled by supplying a suitable medium to the duct 25. The apparatus includes also a hood and fan for drawing off fumes, a transformer for supplying current at the desired voltage to the bus-bars, and a washing tank. |
