Mechanical properties of TiNx/Cr1−xN thin films on plasma nitriding-assisted AISI H13 steel

In this paper, the effects of duplex treatment consisting of plasma nitriding and PVD hard coating on the surface properties of hot working tool steel were investigated. Three different coatings (TiN, CrN single layer coating and TiN/CrN multi-layer coating) were deposited on pre-plasma nitrided AISI H13 steel using unbalanced magnetron sputtering method and their oxidation and mechanical properties such as hardness, adhesion and impact resistance were comparatively examined. The duplex TiN/CrN coating showed the hardness value of 36 GPa (TiN: 26 GPa and CrN: 22 GPa) and much superior adhesion property (Lc=43 N) to other specimens. From the impact test results, all specimens displayed almost identical impact characteristics at room temperature, but it was noted that the duplex TiN/CrN coating showed comparatively less cohesive and adhesive failures than other specimens at 550 °C, suggesting that the duplex TiN/CrN coating seemed to be the most suitable coating method among all those tested.