Method for chemical precipitation of metallic silver powder via a two solution technique
US6110254A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1999 |
| Grant date | Aug 29, 2000 |
| Priority date | — |
| Expiry date | Feb 24, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S75/955
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for the chemical precipitation of metallic silver powder employs a two solution technique in which a solution of a tin salt and a solution a silver salt are mixed in the presence of an inorganic or organic acid, alumina, an anionic surfactant, and a colloid to form a precipitation solution at a temperature and pH suitable to effect the chemical precipitation of silver. Almost 80% by weight of the precipitated powder agglomerate is less than 25 .mu.m in diameter, and the individual powder particles which compose the agglomerate range in size from 0.2 to 2.0 .mu.m. In addition to the favorable size distribution, silver particles precipitated in the presence of a gelatin colloid can be used with a minimal amount of sieving so that little work hardening is imparted to the particles. The powder can be annealed at a temperature of up to 750.degree. C. for two hours in air with minimal sintering, and the acid-assisted hand consolidation of powder produced according to the present technique is capable of producing silver compacts which are nearly 80% dense. Advantageously, a hand consolidated silver compact which comprises the powder of the present invention equals or exceeds the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.