Wetting transition phenomenon in rapidly solidified Al – In alloys

Abstract

This work presents a continuation of the research carried out on RS Al-In alloys and is aimed to reveal how surface chemistry affects wetting properties of alloys. The Rutherford backscattering spectroscopy (RBS) was used for elemental depth profile analisys of RS Al-In alloys containing from 0.02 up to 5.5 at % In to study the chemical composition in the outermost layers of the surface. It was found that In concentration at the thin surface layer (0,02 μm) of RS foils exceeds manyfold its concentration in the bulk. Revealed degree of In enrichment in the near-surface region is maximal at low concentrations of In in alloys. In addition, the concentration effect of alloying element on the surface contact angle (CA) of distilled water was also investigated. Pronounced wetting transition from the homogeneous Wenzel state to the heterogeneous Cassie-Baxter state is discussed in terms of the penetration of water into the micro/nanostructures of foil surfaces.