The effect of particle size on the erosion of a ductile material at the low particle size limit

The intrinsic particle size dependence of erosion rate was investigated in the absence of aerodynamic effects. An apparatus was designed to impact sma ll particles on metallic substrates at normal incidence in vacuum. Two type s of target materials, Cu-30% Zn and pure Ti, were impacted with SiO2 parti cles with average diameters of 2, 5 and 25 mu m. The velocity of impact was 12 m/s. Damage processes induced by single particles were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). This latter technique allowed for the measurement of impact profiles, both of t he cut surfaces and the associated displaced material pile-ups. The impacts produced were in many cases asymmetrical, and the asymmetries appeared to be related to the orientation of the impacted surface. The appearance of th e damage was essentially the same for all three sizes of the erodent, and f or two different substrate materials having different crystal structures. ( C) 1999 Elsevier Science S.A. All rights reserved.