The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1989
Filed:
Oct. 07, 1987
Dieter Hauffe, Frankfurt am Main, DE;
Rainer Kuhna, Frankfurt am Main, DE;
Gerhard Muller, Hanau, DE;
Werner Rausch, Oberursel, DE;
Helmut Schumichen, Frankfurt am Main, DE;
Metallgesellschaft Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
Disclosed is a process of producing a phosphate coating on a composite part consisting of steel and galvanized steel, which comprises alkaline cleaning, rinsing with an aqueous rinsing bath, and phosphatizing with an aqueous zinc phosphate solution. The formation of a non-uniform coating and of spots is avoided in the process of the invention by the use of a rinsing bath which contains at least 0.2 g/l alkali borate, at least 0.1 g/l alkali silicate and at least 0.05 g/l alkali nitrite, and which preferably contains said components in a total up to 5 g/l. If the composite part is to be activated with an activating bath which contains titanium phosphate before being contacted with the zinc phosphate solution, the activating bath must contain at least 1 g/l and preferably up to 4 g/l of tetraalkalipyrophosphate. The process of the invention can be used to prepare composite parts of steel and galvanized steel for subsequent painting, particularly by electrophoretic dip painting.