Gerhard Collardin Gmbh

Hans Gotta

Karl-Heinz Gottwald

Franz-Heinz Schroll

This invention is directed to a method for treating metal surfaces. More particularly, this invention is directed to an improved method for cleaning, scouring, and activating metal surfaces prior to phosphatization, which comprises contacting said metal surfaces with an aqueous solution comprising primary and/or secondary alkali metal or ammonium salts of orthophosphates and conventional metal cleaning components, the solution having a pH value of from about 6.3 to 8.2, said pH being lower than the pH value of solutions of the corresponding secondary orthophosphates alone having the same concentration; and containing optionally condensed phosphates in an amount corresponding to the amount necessary to soften the water hardness of the water used.

Method of treating metal surfaces prior to phosphatization

In the process for applying a phosphate coating to a ferric surface which comprises spraying an aqueous acidic solution at a pH of 4.3 to 6.5 containing an orthophosphate salt of a cation selected from the group consisting of alkali metals and ammonium, in the presence of oxidizing agent or reducing agent accelerators onto said surface, the improvement consisting of adding to said aqueous acidic solution from 0.05 to 1 gm per liter of a short-chain alkylolamine having from 2 to 4 carbon atoms in each alkylol and from 0.01 to 1.5 gm per liter of at least one non-ionic surface-active wetting agent.

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Weiden, Germany

Hans Gotta