The effect of the structural parameters of multilayer ion-plasma PVD coatings on their strength and wear resistance

Abstract

This study presents a methodology for investigating the mechanical properties of multilayer ion-plasma coatings using scratch testing. The approach includes constructing contact pressure vs. load dependencies for a hemispherical diamond indenter, determining the maximum contact pressure, and identifying the critical failure loads. The results of microscopic analysis of the coatings and their failure modes are reported, along with measurements of microhardness (HV) and relative wear resistance under gas-abrasive wear conditions, performed in accordance with GOST 23.201-78.             Based on the experimental data, correlations were established between strength and wear resistance characteristics and the structural parameters of the coatings, material composition, thickness, and number of layers. A critical (minimum required) thickness of nitride layers was identified, at which the resistance of the coatings to brittle failure increases significantly, by up to 2.5 times.             It is proposed that multilayer ion-plasma coatings enhance wear resistance via two mechanisms: resistance to the formation of primary (nucleation) microcracks and suppression of their propagation at the interfaces between metallic and nitride layers.             The obtained results can be recommended for the design of multilayer coatings based on titanium, vanadium, and their nitrides, intended to reinforce titanium alloy components, compressor blades of stationary gas and steam turbines.