Nucleation and inhibition control during the hydrothermal-electrochemical growth of barium titanate films

The control of the microstructure of BaTiO3 films grown on titanium by the hydrothermal-electrochemical method was investigated. Experiments were cond ucted in a three-electrode high-pressure electrochemical cell in a 0.1M Ba( OH)(2) electrolyte at 150 degreesC. Results showed that the spontaneous ini tial nucleation linked to pure hydrothermal BaTiO3 formation can be inhibit ed by cathodically protecting the titanium electrode from the moment it is immersed in the electrolyte. The application of initial nucleation pulses o f varying cathodic potentials affected the grain size of the deposit. It is suggested that the formation of a titanium oxide layer is a necessary step previous to the nucleation of BaTiO3.