Surface topography and physicochemistry of silver containing titanium nitride nanocomposite coatings

Abstract

Titanium nitride (TiN) is a hard, wear-resistant coating material, which is widely applied to components operating in an abrasive wear environment. When codeposited with silver, the coating forms a nanocomposite structure consisting of nanoparticles of silver embedded in a TiN matrix. TiN/Ag coatings were deposited by cosputtering onto bright annealed stainless steel substrates. By control of the target powers, the silver content of the films was varied in the range of 0–16.7 at. %. The films were characterized using scanning electron microscopy (structure), energy dispersive x-ray spectroscopy (chemical composition), white light profilometry (roughness), atomic force microscopy (topography), and physicochemistry (ΔGiwi, γs, γsLW, γsAB, γs+, and γs−). Silver was heterogeneously distributed throughout the TiN matrix, and increasing the silver content in the TiN surfaces resulted in changes in surface nanotopographies with respect to surface features, grain sizes, and physicochemistry. In particular, a silver concentration of 16.7 at. % resulted in a distinct change in surface nanotopography and features, which were qualitatively demonstrated using visual images, linear profiles, and quantitatively using Rp, Rpm, Rz, and Rt roughness parameters. There were also some changes in γs− with increased silver content. When producing novel surfaces, changes in surface chemistry affect other surface parameters. A thorough analysis of surface parameters is essential since changes may affect the potential end use of the product.