Patent · US Expired

Method of producing protective coatings that are resistant to corrosion and wear on magnesium and magnesium alloys

US4978432A · kind A · utility

31Cited by

1References

19Claims

0Family size

Assignee

Electro Chemical Engineering GmbH · CH

Inventors

Edith L. Schmeling · Brühl, DE
Benno Roschenbleck · Osnabrück, DE
Michael Weidemann · Berlin, DE

Key dates

Filing date	Mar 9, 1989
Grant date	Dec 18, 1990
Priority date	—
Expiry date	Mar 9, 2009

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC25D11/30
WIPO fieldSurface technology, coating
WIPO sectorChemistry

Abstract

A method of producing protective coatings that are resistant to corrosion and wear on magnesium and magnesium alloys by anodic oxidation. In order to obtain coatings that have little or no inherent color, that can be easily colored, and that provide a satisfactory adhesive base for lacquering or subsequent processing, a low-alkali aqueous electrolyte bath containing PA1 (a) borate or sulfonate anions and PA1 (b) phosphate and fluoride or chloride ions and adjusted to a pH of 5 to 11 and preferably 8 to 9 is employed. A direct current is applied and is either briefly turned off or its polarity incompletely reversed to allow the formation of manganese phosphate and magnesium fluoride or magnesium chloride and optionally magnesium aluminate.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.