Electrochemical and Optical Behavior of ZrN-Ag Coatings Deposited by Means of DC Reactive Magnetron Sputtering Technique

Abstract

The formation of nanostructured transition metal nitride coatings by introducing a small amount of silver (Ag) content has been proven to be a good strategy for enhancing the physical properties of these materials. In this investigation, ZrN coatings with different Ag contents were deposited on an AISI 316L substrate using the DC reactive magnetron sputtering technique. The influence of the silver on the chemical composition, morphology, and microstructure was investigated using energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The functional properties, specifically the corrosion resistance and the optical reflectance of the deposited coatings, were investigated using electrochemical impedance spectroscopy (EIS) and UV-Visible-NIR, respectively. The results showed the formation of two nanocrystalline phases, fcc-ZrN and metallic fcc-Ag. On the surface of the deposited coatings, homogeneously distributed silver nanoparticles were observed, and they increased with the Ag atomic content. The chemical composition on the surface showed evidence of the formation of oxides, such as Zr-O and Zr-O-N, before and after the corrosion tests. The corrosion resistance of the AISI 316L substrate and the coatings was improved with the incorporation of Ag, and the optical reflectance increased with increasing the Ag content. Finally, this work investigated the effect of the incorporation of silver into a ZrN matrix for potential use as optical protective coatings.