Modelling particulate erosion-corrosion in aqueous slurries: some views on the construction of erosion maps for a range of pure metals

In studies of erosion-corrosion by solid particles in aqueous conditions, there have been various attempts in recent years to model the process. In particular, predictive models have been developed for steels to chart transitions between erosion-corrosion regimes. Such regimes identify whether the erosion-corrosion process is affected by active dissolution or passivation processes in the aqueous environment. A very important development in the study of aqueous corrosion of pure metals has been the concept of the corrosion map, developed by Pourbaix in the last century. Such maps identify regimes of corrosion, ranging from immunity to active dissolution and to passivation, as a function of pH and electrochemical potential. The position of the boundaries, as a function of the latter variables, may differ significantly for various pure metals. This paper models the erosion-corrosion behaviour for a range of pure metals, i.e. Ni, Al, and Cu (metals which have not been addressed to date using such an approach) and compares the results with a reference metal, Fe. Erosion-corrosion mechanism and wastage maps are constructed based on the results. In addition, materials selection maps are developed based on the results, showing how erosion-corrosion resistance for the materials may be optimised in such conditions