REMOVING METHOD OF NICKEL OXIDE FILM

摘要

PURPOSE:To improve the efficiency of removing an oxide film by immersing the lead of electronic parts into an org. acid soln. such as an aq. oxalic acid soln. or the like then immersing the same into a chemical polishing liquid consisting essentially of hydrogen peroxide and ammonium fluoride. CONSTITUTION:A lead 2 is first immersed in the oxalic acid soln. and the soln. is heated to the temp. near the b.p. and is kept at about 80 deg.C in order to remove an oxide film 3. The oxide film 3 remains on a nickel plating layer 1 even after the treatment with the oxalic acid soln. and therefore the lead is chemically polished for about 1.5min with the 50% aq. soln. of the chemical polishing agent consisting essentially of hydrogen peroxide and ammonium fluoride. The remaining oxide film is thoroughly removed by chemical polishing after the oxide film is removed to some extent by the org. acid according to the above-mentioned method and therefore the effieicncy of removing the film is improved and the removal of the oxide film except the prescribed thickness of the nickel layer is made possible.