Electrochemical characterization and surface analysis of bulk amorphous alloys in aqueous solutions at different pH

Abstract

Bulk amorphous alloys are a new class of materials with a variety of characteristics that make them useful for applications in aqueous environments. While some bulk amorphous metals show increased corrosion resistance, there is still a lack of fundamental electrochemical studies of these materials. Two different compositions of BeCuNiTiZr bulk amorphous alloys have been studied at pH 5, 7, and 10 using cyclic voltammetry (CV), x-ray photoelectron spectroscopy (XPS), depth profiling methods, and optical microscopy. While XPS is used to determine the composition of the resulting oxide films, the CV curves and optical micrographs are compared to pinpoint differences in the corrosion resistance of the amorphous multicomponent alloys. The effect of the amorphicity, multicomponent structure and the presence of elements with widely varying interfacial reactivities on the oxidation process and on the corrosion resistance of the alloys, are discussed with the desire to provide some electrochemical background for the expected wide spread use of bulk amorphous alloys.