Oscillating sliding wear of mono- and multilayer ceramic coatings in air

Abstract

Structural characteristics and mechanical properties of TiN and (Ti,AI)N monolayers, and multilayered (superlattice) (Ti,AI)N/TiN coatings deposited on ASP 23 high-speed steel by different PVD techniques are compared. Coating characteristics such as morphology, composition, cross-sectional structure, hardness and elastic modulus were determined. The effect of TIN interlayers on the hardness and the elasticity of multilayered (Ti,Al)N/TiN coatings was investigated. The friction and wear of these coatings were investigated in unlubricated fretting tests (mode I) performed in air of different relative humidities. The relationship between wear volume and dissipated energy was derived for (Ti,Al)N-based coatings, and the dependence upon relative humidity was checked and compared to the one found earlier for TiN coatings. (Ti,Al)N-based coatings exhibit a lower wear rate (mu m(3) J(-1)) at increasing relative humidity, whereas TiN has a constant wear rate independently of the relative humidity. Multilayered (Ti,Al)N/TiN coatings show an improved fretting wear resistance in comparison to monolayer (Ti,AI)N coatings. (C) 1999 Elsevier Science S.A. All rights reserved.