Method and composition for selectively stripping nickel from a substrate
US7591956B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 2006 |
| Grant date | Sep 22, 2009 |
| Priority date | — |
| Expiry date | Oct 26, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/0361
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of stripping nickel from a printed wiring board comprises providing a printed wiring board with a nickel deposit on a surface and contacting the nickel deposit with phosphate ions and an oxidizer. An aqueous solution comprises ammonium ions, phosphate ions and an oxidizing agent present in amounts effective to strip nickel. An aqueous solution comprises about 1% to about 10% by weight hydrogen peroxide and about 5% to about 30% by weight of an ammonium phosphate. A method of pre-treating a copper substrate comprises providing a printed wiring board having a copper substrate and contacting the copper substrate with phosphate ions, and an oxidizer. A method of neutralizing permanganate on a printed wiring board comprises providing a printed wiring board with a permanganate residue on the printed wiring board and contacting the permanganate residue with phosphate ions, and an oxidizer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.