Parametric study of the mechanical properties of nanocrystalline TiN/CrN multilayer coatings with a special focus on the effect of coating thickness and substrate roughness

In a plot to improve the performance of steel mechanical parts subject to aggressive friction solicitations, three batches of deposits of TiN and CrN layers on steel substrates with two different roughnesses have been obtained using reactive DC magnetron sputtering. The present study was conducted to determine the effect of varying TiN/CrN multilayer coatings thickness (varying modulated period. and interlayer thickness), on their mechanical and tribological properties. The morphological and the structural properties were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The nanoindentation measurements displayed improvement in hardness (> 40 GPa) and Young's modulus (> 600 GPa) for the coating with Lambda similar or equal to 12 nm (TiN Lambda/2 congruent to 7.5 nm + CrN Lambda/2 congruent to 4.5 nm) thickness and the higher number (300) of interfaces, deposited on the rougher substrate. Its low coating damage under the scratch test, associated with its estimated adhesion work (Wad), indicated a good cohesive/adhesive strength and improved structural and mechanical properties.

Automated summary

The study focused on improving the performance of steel mechanical parts subject to aggressive friction solicitations by depositing TiN and CrN layers. It was found that multi-layer coatings with a certain thickness and a higher number of interfaces showed excellent hardness and Young's modulus, as well as good cohesive/adhesive strength and improved structural and mechanical properties.