HVOF thermal sprayed coatings on aluminium alloys and aluminium matrix composites

This project is concerned with the investigation of the capability of HVOF thermal spraying to improve the tribological and mechanical properties of aluminium alloys and aluminium matrix composites (AMCs). The present study describes and compares the mechanical and tribological properties of CCr–NiCr and WC–CoCr thermal sprayed HVOF coatings deposited on three different substrates: steel, aluminium alloy and aluminium matrix composite. The coating microstructures were characterised by SEM and optical microscopy. Differences in roughness have been determined by profilometry. The ultra-microindentation technique was applied to measure the hardness and the elasto-plastic properties of the coatings. Experiments using a tribometer (pin on disc configuration) under lubricated and dry conditions have been performed in order to evaluate the friction and wear properties of the different systems. The morphology of the wear tracks after pin on disc tests was characterised using SEM microscopy and profilometry with the aim of studying the wear mechanism.