Hydrothermal‐Electrochemical Formation of BaTiO, Films: Electrochemical Characterization of the Early Stages of Growth

Abstract

The formation mechanism of BaTiO, films produced by a hydrothermal‐electrochemical method was characterized using electrochemical techniques. Experiments were conducted in a three‐electrode electrochemical cell, with titanium foil as the working electrode and Ag/AgCl as the reference electrode, in a 0.25M Ba(OH)2 solution at 150°C. Hydrothermal‐electrochemical BaTiO, film formation is initially controlled by charge transfer related to the rate of electrochemical oxidation of titanium. The process later becomes mass transfer controlled, presumably related to the diffusion of Ba2+ ions across the built‐up BaTiO3 film. A relation between the mechanism of formation of BaTiO, films under both the hydrothermal‐electrochemical and the pure hydrothermal methods was established.