Compositions for the treatment of magnesium alloys
US7094327B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 2003 |
| Grant date | Aug 22, 2006 |
| Priority date | — |
| Expiry date | Jan 31, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D11/30
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to a composition for treating magnesium alloys aimed at improving the resistance thereof to corrosion. The composition is an aqueous solution with a pH ranging between 7 and 10, containing a niobium salt, hydrofluoric acid, and optionally a zirconium salt, phosphoric acid, and boric acid. The alloy is treated in an electrochemical cell in which said alloy acts as an anode. The cell contains an inventive composition at a temperature between 20° C. and 40° C. as an electrolyte. An initial voltage which is sufficient to create a current density between 1.5 and 2.5 A/dm2 is applied to the cell, whereupon the voltage is progressively increased to a level ranging between 240 and 330 V in order to maintain the initial current density.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.