Experimental analysis of corrosion and erosion phenomena on metal surfaces by nanofluids

In the present work an analysis of experimental data obtained exposing metallic targets to the flow of a number of nanofluids has been carried out. The investigated suspensions were composed of typical nanometer-sized solid particles, such as TiO2, Al2O3, SiC, and ZrO2 at different concentrations, suspended in different base fluids. The effects of the flow of these nano-materials on three reference targets made of commercial metals (aluminum, copper, and stainless steel) have been assessed. An accurate analysis of the results showed that, where present, the observed damages are caused by chemical corrosion rather than by mechanical erosion, the pH of the suspension being the most important parameter. Conversely, no influence of the particles' nature and content was found, even at high concentrations of nanoparticles (up to 20% by weight). This is believed to be a useful information about the practical feasibility of advanced systems, like in heat transfer applications, based on the use of these relatively new fluids. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.