Method for the treatment of alloy steels and refractory metals

US5372655A · kind A · utility

Assignee

• Leybold Durferrit GmbH · DE

Inventors

• Friedrich Preisser · Heitersheim, DE
• Peter Minarski · Rodenbach, DE
• Albrecht Melber · Darmstadt, DE
• Klaus Zimmerman · Alzenau, DE

Key dates

• Filing date: Apr 14, 1992
• Grant date: Dec 13, 1994
• Expiry date: Apr 14, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C8/80
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Method for the treatment of alloy steels and refractory metals such as Ti, Zr and Nb, especially for depassivation and subsequent thermochemical surface treatment in a process chamber (1, 2) under the action of pressure and temperature, wherein, in a first process step, a first gas or gas mixture from the group N.sub.2, H.sub.2 or NH.sub.3 is admitted for the depassivation into a process chamber (1), a pressure greater than 1 bar a and a temperature between 100.degree. C. and 1,000.degree. C. is established in the chamber (1), and in a second process step a second gas or gas mixture from the group of N-, C- or B-containing gases is admitted into a process chamber (1, 2) for the thermochemical surface treatment, and a temperature between 100.degree. C. and 1,000.degree. C. at a pressure greater than or equal to 1 bar a is established.