Carbonitriding

From GAWDAwiki

Carbonitriding is a case hardening process in which a suitable ferrous material is heated above the lower transformation temperature in a gaseous atmosphere of such composition as to cause simultaneous absorption of carbon and nitrogen by the surface and, by diffusion, create a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the workpiece.^[1]

References

1. http://www.corrosionsource.com/handbook/glossary/c_glos.htm