Method of blackening surfaces of steel parts with wet nitrogen
US4448612A · kind A · utility
6Cited by
4References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 3, 1983 |
| Grant date | May 15, 1984 |
| Priority date | — |
| Expiry date | May 3, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C8/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A gaseous mixture of nitrogen and water vapor (dew point of about -8.degree. to 32.degree. C.), heated to 550.degree. to 750.degree. C., contacts the surfaces of a steel part for a sufficient time to produce adherent, deep-black layers on the part. Steel aperture masks and support frames for color television picture tubes may be blackened by the novel method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.