Fluidized bed method of forming a nitride or carbonitride layer
US4871401A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1987 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | Nov 13, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C12/02
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of forming a nitride or carbonitride layer on the surface of an iron or iron alloy article, which comprises the steps of: (a) disposing in a fluidized bed furnace a treating agent comprising a refractory powder, a metal powder of at least one selected from the group consisting of chromium, vanadium, titanium and a metal containing at least one of the chromium, vanadium and titanium, and a halide powder; (b) introducing a nitrogen-containing gas into the fluidizied bed furnace; (c) heating the fluidized bed furnace; and (d) disposing the article in the fluidized bed furnace during or after the steps (a) to (c). In this method, the article is preferably treated at a temperature not higher than 650.degree. C. The step (c) may precede the step (b). The halide powder may be supplied to the fluidized bed furnace from outside in the form of green compact or a gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.