Reducing or avoiding surface irregularities in electrophoretic painting of phosphated metal surfaces

摘要: The phenomenon of 'mapping' (surface defects) after electrophoretic painting over phosphate conversion coatings passivated with hexavalent chromium containing passivating compositions can be avoided or reduced by keeping the surface being treated constantly wet from time it is coated until electrophoretically painted, preceding step treatment an aqueous liquid composition comprising at least one following components: (A) a water soluble and/or dispersible polymer weight average molecular 500; (B) fluorometallic acids and anions thereof, molecules which consist (i) atom boron, silicon, zirconium, iron, aluminum, titanium, (ii) four fluorine atoms, and, optionally, (iii) more atoms oxygen, hydrogen, both; (C) zirconium salts ethylenediamine tetraacetic acid; (D) alkali metal ammonium zirconyl carboxylates carbonates; replacing same type as described above.