Method of plasma nitriding of metals via nitrogen charging
US7556699B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Jun 17, 2004 |
| Grant date | Jul 7, 2009 |
| Priority date | — |
| Expiry date | Apr 20, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12458
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of nitriding a metal includes transforming a surface region of a generally nitrogen-free metal into a nitrogen-containing solid solution surface region. A first heating process heats the surface region at a first temperature in the presence of a nitrogen gas partial pressure to form a nitrogen-charged surface portion on the surface region. A second heating process heats the surface region and nitrogen-charged surface portion at a second temperature for a predetermined time to interstitially diffuse nitrogen from the nitrogen-charged surface portion a depth into the surface region. Coincident with the second heating process, an ionized inert or reducing gas removes the nitrogen-charged surface portion. The resulting nitrogen-containing solid solution surface region has a gradual transition in nitrogen concentration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.