Wear and cavitation effect in an epoxy filled with boron and silicon nanocarbides

Abstract

Cavitation is a complex process that includes the steps of nucleation, growth, coalescence, collapse and successive rebound of bubbles and/or clusters of vapour and/or gas in a liquid when varying its thermodynamic and hydrodynamic conditions during short periods of time. When cavitation occurs close to the surface of a solid, it causes localized damage due to the high impact pressures that exceed the yield strength of the material and/or as a consequence of the fluctuating stresses that promote surface fatigue. In many systems like hydraulic equipment, fluid pump impellers, ship propellers and steam turbines, etc. mechanical erosion can be a great problem. For this reason, a growing interest in polymer coatings for tribological applications has emerged in the last years, being epoxy resins are good candidates. This work focused on the analysis of surface damage of nanocomposites as epoxy-based coating. The epoxy resin used was a commercial resin, the fillers were boron and silicon carbides with particle size of 60 and 100 nm respectively, and they were used in two percentage (6 and 12 wt.%). Pin on disk test were carried out to evaluate wear. Cavitation test were performed on aluminium specimens coated with the nanoparticles/epoxy composites, to evaluate their effectiveness as wear-resistance coating. Wear tracks and cavitation samples were studied by Scanning Electron Microscopy (SEM). The results showed higher wear resistance of nanocomposites than clear epoxy resin, and also better cavitation resistance.