Patent · US Expired

Alkaline strip passivation

US6346295B1 · kind B1 · utility

3Cited by

5References

12Claims

0Family size

Assignee

Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

Joerg Riesop · Niederzier, DE
Heike Krautbauer · Kerpen, DE

Key dates

Filing date	Apr 5, 2000
Grant date	Feb 12, 2002
Priority date	—
Expiry date	Apr 5, 2020

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC23C22/83
WIPO fieldSurface technology, coating
WIPO sectorChemistry

Abstract

Process for the alkaline passivation of galvanized and alloy-galvanized steel surfaces and of aluminum in strip lines, wherein the metal surfaces are brought into contact with an alkaline aqueous solution that contains complexing agents and iron, which has a free alkalinity in the range of 5 to 20 points and a total alkalinity in the range of 7 to 30 points and contains:0.1 to 1 g/l magnesium ions,0.1 to 1 g/l iron (III) ions and0.5 to 5 g/l amino or hydroxy carboxylate ions. This may be followed by a chrome-containing or chrome-free secondary passivation.

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