Regeneration agent for carburization salt bath

US4509993A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Hans-Hermann Beyer · Munich, DE
• Ulrich Baudis · Hanau, DE
• Peter Biberbach · Rodenbach, DE

Key dates

• Filing date: Dec 29, 1983
• Grant date: Apr 9, 1985
• Expiry date: Dec 29, 2003

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C8/40
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

It is known to regenerate salt baths for nitriding parts of iron and steel with polymers of organic materials, which polymers, however, could not be used in carburizing salt baths since with them there only are formed slight amounts of carburizing active cyanide, the baths foam, and carbon residues are formed. An excellent regeneration agent for carburizing salt baths is obtained by using polymeric organic compounds of the overall composition [C.sub.6 H.sub.x N.sub.y ].sub.z where x is 3 to 5, y is 5 to 8, and z is 10 to 10,000. These compounds are obtained by reacting formaldehyde with cyanamide and/or dicyandiamide and/or melamine and pyrolytically decomposing the reaction product at 300.degree. to 600.degree. C.