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:
Aug. 04, 1992
Filed:
Aug. 23, 1991
Horst Gehmecker, Hofheim, DE;
Thomas Kolberg, Heppenheim, DE;
Dirk Meyer, Frankfurt, DE;
Gerhard Muller, Hanau, DE;
Metallgesellschaft Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
For phosphating metal surfaces which consist at least in part of aluminum, by means of phosphating solutions which contain zinc, phosphate and fluoride, any titanium which has entered the phosphating solution and would disturb the formation of the layer is precipitated by an addition of SiO-containing compounds and after the precipitate has been removed, the content of free fluoride is readjusted to the required concentration. Particularly suitable compounds which contain SiO, consist of alkali metasilicate, alkali orthosilicate and/or alkali disilicate, preferably used in an amount of 0.05 to 1 g/l of the phosphating solution, or of silica, which is preferably used in an amount of 0.5 to 10 g per liter of the phosphating solution (calc. as Si).