Method for producing and oxide layer on metallic elements
US7115174B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 2002 |
| Grant date | Oct 3, 2006 |
| Priority date | — |
| Expiry date | Dec 24, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T50/60
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
In a known method for producing an oxide layer on metal parts, the metal parts are heat-treated in a treatment chamber during a carburization phase at temperatures below 1100° C. [2012° F.] in an atmosphere containing carbon monoxide and hydrogen and then, during an oxidation phase, they are oxidized at an oxidation temperature in the range from 750° C. to 950° C. [1382° F. to 1742° F.] in an atmosphere where a PH2O-to-PH2 ratio between 0.3 and 10 has been established by feeding an oxidant into the treatment chamber, a process in which an oxide layer is formed, whereby the oxygen partial pressure is determined by means of an oxygen probe and regulated at least during the oxidation phase. In order to improve the known method in terms of the reproducibility of the formation of corrosion-resistant coatings that cover and adhere well on metal parts containing iron and so as to improve the cost effectiveness of the process, it is proposed according to the invention that the oxygen partial pressure be regulated in such a way that the oxygen probe indicates a probe voltage in the range from 890 mV to 940 mV.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.