Physical and electrochemical properties of vanadium alloy oxide layers prepared by anodic passivation

Abstract

Abstract. Thin oxide layers of high purity metals are suitable as redox electrodes in aqueous solutions. Concentrations of hydrogen peroxide could be analyzed potentiometrically. In dependence on the pH-value Nerstian behaviour was observed in the range of 0.1-30 g/I (H202) approximately. It is assumed that this electrochemical behaviour of the oxide layer is mainly influenced by electronic and ionic defects. Alloys of vanadium and titanium are included in the investigation. In order to clarify the mechanism in detail, electrochemical measurements (voltammetry, EIS) and surface analytical investigations (XRD, AES, XPS) have been carried out.

Study of the structure of passivated vanadium-titanium alloys and their semiconductor properties

“…Because of the current the mass transfer increases and so does corrosion. These results are in accordance with electrochemical investigations [12] and also with the consideration that in the system n-type semiconductor/redox electrolyte electron transfer proceeds mostly via the conduction band (energy level of the redox system overlaps with the conduction band). According to Habermann [5] there is a correlation between the mean conductivity of the passive layer and its selectivity in electrochemical systems.…”

“…If this model is applied to anion adsorption the flat band potential would be shifted from -300 for Ti to 400 mV for V-20Ti, and the border potential for the starting of pitting corrosion is shifted into the anodic area. In contrast with the measurements of Bachmann et al [12] it must be recorded that corrosion increases as the amount of vanadium is increased, i.e. those investigations cannot be interpreted by use of this simple electrostatic model.…”