Effect of Nitrogen Partial Pressure on Structure, Mechanical Property, and Corrosion Behavior of ZrNx Films Prepared by Reactive DC Magnetron Sputtering

Abstract

ZrNx films were deposited by DC magnetron sputtering with pure Zr target in different nitrogen partial pressure atmospheres ( $r={\text{N}}_2/\left[\text{Ar}+{\text{N}}_2\right]$ ). The structure and composition of the thin films were characterized as a function of $r$ using scanning electron microscope, glancing angle X-ray diffraction, and X-ray photoelectron spectroscopy. The hardness, adhesive strength, and corrosion behavior of the coatings were measured by nanoindentation, microscratch, and potentiodynamic measurements in 3.5 wt% NaCl solution. The results show that the structure of the ZrNx films changes from a nearly stoichiometric ZrN with a typical columnar structure to mixed phases composited of ZrN and α-ZrNx with a dense glass structure as $r$ increases from 12% to 50%. The mechanical properties including hardness, elastic modulus, and adhesion decrease with increasing $r$ due to nonstoichiometric compound and glass phase structure of the coatings, while the dense glass structure significantly improves the corrosion inhibition.