Tribocorrosion behavior of plasma nitrided Hardox steels in NaCl solution

In this study, the effect of plasma nitriding treatment on structural, wear, corrosion and tribocorrosion properties of different type Hardox steels (400, 450 and 500 type) was investigated using X-ray diffraction, microhardness tester, scanning electron microscope, 3D profilometer and reciprocating wear tester coupled with electrochemical corrosion cell. The plasma nitriding treatments were performed in 50%N2-50%H2 gas mixture at 500 °C for 1 and 4 h. The tribological tests were carried out in dry and open circuit potential conditions at 10 N normal force in 3.5% wt. NaCl aqueous solution at room temperature. Nitriding changed the electrochemical degradation mechanism of surface to pitting corrosion. Plasma nitriding time of 1 h significantly improved the corrosion and wear resistance of the Hardox steels.