The effect of steel substrate pre-hardening on structural, mechanical, and tribological properties of magnetron sputtered TiN and TiAlN coatings

• The nitrocarburization enables to increase the microhardness by 7 times.
• The thermochemical treatment enables to increase the wear resistance up to 2.3 times.
• A new method for determining wear resistance of the deposited coatings is proposed.
• The non-additive effect of nitrocarburization and PVD coating deposition was discovered.

The effect of pre-hardening of steel substrate on mechanical and tribological properties of TiN and TiAlN coating–steel substrate composites was studied for various treatment conditions. We have found that prior nitrocarburization of the steel substrate increases the microhardness by 7 times, the wear resistance of the working surface of the composite up to 2.3 times, the resilience of the composite by 4.5 times. It is thus feasible to produce thinner coatings in composite layered systems with no drawbacks regarding performance. We also suggest a method to determine wear resistance of the deposited coatings, as well as to estimate the influence of the hardness gradient and contribution of all layers to overall durability of such layered systems.