Structure-Dependent Tribological Investigation of Hierarchically ZrN-Coated Low-Carbon Steel for Automotive Applications.

Due to the growth of automotive industries, the requirement for engine and structural parts having longer lifetime has been also increased. Transition metal nitrides, especially thin films, attract attention due to their effective mechanical and tribological features. In this study, hierarchal nanostructural coatings (nanocauliflower, nanopyramids and nanoflakes) of zirconium nitride (ZrN) were deposited by reactive magnetron sputtering system on a low-carbon steel plate (LCSP) substrate. The fabricated nanoflake (ZrNNF) coating show promising properties such as higher elastic modulus (335.195 ± 16.75 GPa) and high hardness (33.173 ± 1.65 GPa). It has been assessed how the friction coefficient varies with cycle time. The surface chemistry, structure and hardness of the coatings covering the surface effect wear volume and friction levels. The dominant wear mechanisms were identified using FE-SEM, EDX and XPS analyses. During the process of wear, zirconium oxynitrides (O-Zr-N) were formed in the ZrNNF coating, which can have a positive effect on automotive applications. The wear volume of the ZrN nanoflake hard coating was lower compared to pristine samples. The nanostructures such as nanocauliflower, nanopyramids and nanoflakes can be a plausible explanation for the improved tribological performance. [ABSTRACT FROM AUTHOR]