Method for circulating electroless nickel plating solution
US6245389A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 26, 1998 |
| Grant date | Jun 12, 2001 |
| Priority date | — |
| Expiry date | Aug 26, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A20/131
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of circulating an electroless nickel plating solution is characterized in that the system comprises the following process steps effected in the following order: (A) a step of electrolessly plating nickel using a plating solution having nickel hypophosphite contained as a chief chemical material for supplying a plating metal ion Ni.sup.2+ and a hypophosphorous acid ion H.sub.2 PO.sub.2.sup.- acting as a reducing agent; (B) a step of removing HPO.sub.3.sup.2- from a plating solution that has aged in the step (A); (C) a step of desalting the mother liquor separated from the step (B); and (D) a step of adjusting the components of the treated plating solution and then circulating same back into the step (A) of electroless nickel plating. According to the present invention, the plating solution is free from the formation and accumulation of a sulfuric acid salt and hence a long service life is ensured and a great advantage in environmental protection is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.