AISI 304 nitrocarburized at low temperature: Mechanical and tribological properties

In the present work, the effects of 300 °C glow discharge nitrocarburizing process on structural, mechanical and tribological properties of AISI 304 stainless steel are reported. The carbon amount (CH4) in the nitriding atmosphere (N2) was 2% and the working times were from 0.5 to 4 h. Surface mechanical and tribological behaviors in the modified surfaces were studied by using instrumented indentation and reciprocating sliding techniques. At the employed nitrocarburizing atmosphere and for all of the processing times two types of expanded austenite (γC and γN) were formed. High hardness such as 10–11 GPa in comparison to the low matrix hardness (2.5 GPa) was obtained in a shallow plateau-like shape. The surface hardening increases the wear resistance by a factor of five in respect to untreated steel. These improvements were obtained at all nitrocarburizing times.