Influence of chromium on the chemical composition and surface properties of rapidly solidified Al–Cr alloys

Abstract

The microstructure and physicochemical properties of the surface of rapidly solidified Al–Cr alloys containing 1 and 3 at % of chromium are studied by means of photoelectron microscopy using synchrotron radiation, scanning probe microscopy, and the sessile-drop technique. We find that the surface oxidehydroxide layer of foils has a heterogeneous structure with highly dispersed chromium inclusions (possibly clusters). Chromium and aluminum are predominantly in a metallic state in chromium-enriched regions of the foil surface. We find that the equilibrium contact angle of wetting of the samples with water depends on their morphology and the concentration of chromium in the alloys. The wettability is mainly determined by the chemical composition of the surface of foils and to a lesser extent its roughness. A decrease from poor to low water wettability of rapidly solidified Al–Cr alloys with an increase in the chromium concentration up to 3 at % is due to the aggregation of chromium inclusions.