Abstract: Workpieces vertically suspended on carrier bars in side-by-side relation are dipped into an electrolyte bath which has a plurality of electric contact plates of alternating polarity spaced along one side. Electric energy is applied to the workpieces from the plates through the carrier bars and the successive work pieces serve as electrodes of opposite polarity, the polarities reversing as the individual carrier bars are advanced from plate to plate.

Abstract: A method for inexpensively producing a colored anodized film on aluminum or aluminum alloy material by electrolyzing the aluminum material in a sulphuric acid bath in the presence of a resistivity agent selected from trivalent aluminum ions and oxalic acid, by applying thereto a pulsating electric current having a peak voltage of 25 to 45 volts and a pulse duration of 5 to 70 milliseconds (m.sec.) and a ratio of pulse frequency to pulse duration of between 2 and 7.

Abstract: A method of forming an oxide film on the surface of an aluminum material by anodizing the aluminum material in an aqueous solution containing 0.5 to 10% by weight of oxalic acid and 0.05 to 1.0% by weight of sulfuric acid, in which either an electrolyzing voltage or the temperature of the aqueous solution is controlled in the range of 5 to 150V or 0.degree. to 40.degree. C, whereby the oxide film is colored in color tone from bronze to silver.

Abstract: A process is disclosed for producing a firmly adhered, corrosion resistant film on an aluminum or aluminum alloy surface by means of anodization using an electrolyte containing at least one of the compounds selected from the group consisting of quaternary ammonium salts, aliphatic primary amines and aliphatic secondary amines which compounds act upon a coating to cause the same to adhere intimately to the aluminum surface on one hand and impart corrosion resistance to the latter on the other.

Abstract: Surface treating apparatus comprising treating bath means; a carrier bar having devices for vertically suspending workpieces; lifting means provided at the sides of the bath means for vertically conveying the carrier bar and dipping said workpieces into and out of said bath means, the lifting means also including means for conveying the carrier bar in a substantially horizontal direction; loading means rotatable between a horizontal and a vertical position and adapted to removably receive the carrier bar having workpieces attached in the horizontal position for loading the carrier bar onto the lifting means in the vertical position; unloading means rotatable between a horizontal and a vertical position and adapted to receive the carrier bar supporting finished workpieces in the vertical position, the workpieces being released from the carrier bar when the unloading means is in a horizontal position; and returning conveyor means between the loading and unloading means so that the carrier bar moves from the loa