Surface hardness of articles by reactive phosphate treatment
US6074699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1994 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Apr 29, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2111/00482
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An article has at its surface a nonmetallic ceramic form of a cation reactive with phosphate ion to form a ceramic phosphate, such as an oxide of a cation selected from the group consisting of beryllium, aluminum, iron, magnesium, calcium, thorium, barium, zirconium, zinc, silicon, and mixtures thereof. A source of reactive phosphate ions, such as concentrated phosphoric acid or monoaluminum phosphate, is applied to the surface of the article. The surface of the article is thereafter heated to cause the nonmetallic ceramic form of the cation and the source of the reactive phosphate ions to react together, producing a phosphate-bonded hard layer at the surface of the article.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.