Electrochemical preparation of oxide materials for electrochemistry and electronics

Electrochemical formation of barium tungstate (BaWO4) was studied as a model case of electrochemical formation of an advanced oxide material for electronics. BaWO4 is formed on the surface of tungsten electrode during oxidation in alkaline media (pH > 12) containing a corresponding cation. The analysis of electrochemical as well as electrochemical quartz crystal microbalance (EQCM) data taken during these experiments identifies at least three qualitatively different steps composing the electrode process. Effects of the potential, applied current density and alkaline earth metal cation concentration are demonstrated using cyclic voltammetry and galvanostatic experiments. Specific constraints of the ECC formalism for the electrochemical oxide deposition following from the galvanostatic data are discussed.