Hydroabrasive wear behaviour and damage mechanisms of different hard coatings

A broad range of different types of hard coatings were investigated under a brasive-erosive conditions. The slurry used in this investigation is compos ed of water and quartz sand (silica sand). Using different size distributio ns 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 ava ilable thermal, thermomechanical and diffusional coatings as well as coatin gs produced by physical vapour deposition (PVD) techniques, deposited on th ree different substrate materials, were investigated. A general result is t hat the wear behaviour of the different coatings seems to be governed prima rily by the microstructure rather than by the coating process. Particular t hermomechanical plasma- or detonation-sprayed coatings lead to a marked imp rovement of the wear resistance in comparison to the behaviour of the non-c oated substrate. The wear behaviour of selected coating/substrate systems w as ranked and discussed by taking into account the different microstructure s and damage mechanisms. (C) 1999 Elsevier Science S.A. All rights reserved .