  Present work was aimed to investigate the effect of nitriding time; 1, 1.5,
2.5 & 3.5 h, on surface characteristics & mechanical properties (surface
nano-hardness, hardness Vickers, and adhesion) of AISI M2 tool steel.
Mechanically effective compound (4 to 17.6 um) and diffusion layers (50.8 to
82.4 um) were obtained. Plasma nitriding considerably improved Surface
engineering has been recognized as a family of technologies used to modify or
improve the surface properties of a substrate. Nano-hardness, E-moduli and
resistance to scratch of AISI M2 steel. Surface properties enhancement was
associated to two harmonious effects at the nano-scale resulted by (a) stable
nitride phases formation such as: gamma-Fe4N, epsilon-Fe2,3N, and (b) no
brittle nitride networks and no critical decarburization of the steel upon
nitriding. Thermodynamic calculations are in agreement with the experimental
findings.

Materials Science