REMOVING METHOD OF OXIDE ON METALLIC SURFACE

PURPOSE:To accelerate the dissolving and removing reaction of the oxide on a metallic surface in the stage of dissolving and removing the oxide with a neutral washing liquid having weak corrosiveness by incorporating hydrogen in the washing liquid and bringing the metal to be treated into electrical contact with the other specific metal. CONSTITUTION:Electric current is conducted between an anode 8 and a cathode 7 of an electrolytic cell 1 segmented by a cation exchange membrane 6 to an anode chamber 4 and a cathode chamber 5 from a DC power source 9 to electrolyze the neutral washing liquid circulated in the cell 1 to a dissolving cell 2 by a pump 3. H2 is generated by the cathode 7 and the washing liquid 10 contg. H2 is circulated to the inside of the cell 2. A metal 11 requiring dissolution and removal of the oxide on the surface is dipped in the cell 2 and at the same time a Pt, Pd, Ni, steel, stainless steel or carbon piece 12 is dipped therein and is electrically connected to the metall 11 by a lead wire 13. Electron is injected by H2 into the oxide film of the metal 11, by which only the oxide film is dissolved and removed at a high speed without corroding the base metal by the neutral washing soln. having weak corrosiveness.