Hydroabrasive wear behaviour and damage mechanisms of different hard coatings

Abstract

A broad range of different types of hard coatings were investigated under abrasive–erosive conditions. The slurry used in this investigation is composed of water and quartz sand (silica sand). Using different size distributions of the silica-sand particles, two-body and three-body abrasive wear were simulated. Supplementary microstructural investigations were performed to reveal the main damage mechanisms. In this work, different commercially available thermal, thermomechanical and diffusional coatings as well as coatings produced by physical vapour deposition (PVD) techniques, deposited on three different substrate materials, were investigated. A general result is that the wear behaviour of the different coatings seems to be governed primarily by the microstructure rather than by the coating process. Particular thermomechanical plasma- or detonation-sprayed coatings lead to a marked improvement of the wear resistance in comparison to the behaviour of the non-coated substrate. The wear behaviour of selected coating/substrate systems was ranked and discussed by taking into account the different microstructures and damage mechanisms.