Bath for the electrolytic remove of metallueberzuegen of the bottom mold bodies from tempered or nitrided steel

摘要

It is carried out rapidly and without damage to the substrate by using an electrolyte of ammonium nitrate or amines and nitric acid in a solution buffered to pH 5.0-7.0 by ammonium acetate. The bath is activated by small additions, when the substrate is a stainless steel, of soluble chlorides and/or thiocyanates, or, when the substrate is a quenched or nitrided steel, of an aromatic hydrocarbon having a hydroxyl group linked directly to the benzene ring. The solution is suitable for dissolution of Ni coatings; for Cr, Zn, Sn, Cu, Cd or Ag coatings, the activating additions are not necessary.