Method of compacting anodized metals with lithium and fluoride-containing solutions without using heavy metals

US5891269A · kind A · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Torsten Koerner · Goldkronach, DE
• Josef Kresse · Rommerskirchen, DE
• Juergen Lindener · Goldkronach, DE
• Wolf-Achim Roland · Solingen, DE

Key dates

• Filing date: Jan 7, 1998
• Grant date: Apr 6, 1999
• Expiry date: Jan 7, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25D11/246
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process for sealing anodized metals without using any heavy metals comprises a first step in which the anodized metal is contacted for a period of between 3 and 30 minutes (for an anodized layer thickness of 20 .mu.m) with an aqueous solution which has a temperature from 15.degree. to 35.degree. C. and a pH between 5.0 and 6.5 and contains from 0.1 to 3 g/l of lithium ions and from 0.1 to 5 g/l of fluoride ions and a second step in which the anodized metal is contacted for a period from 5 to 30 minutes (for an anodized layer thickness of 20 .mu.m) with water or an aqueous solution of substances which prevent the formation of a sealing coating, the solution having a pH from 5.5 to 8.5 and a temperature from 80.degree. to 100.degree. C.