0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 thick films prepared by electrophoretic deposition from an ethanol-based suspension

We have investigated the processing of 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (denoted PMN-PT) thick films using an electrophoretic deposition process (denoted EPD), with the PMN-PT particles suspended in an ethanol-based suspension. The zeta-potential and the viscosity were measured to identify the conditions for the preparation of a stable suspension suitable for the EPD. The applied voltage, the deposition time, the chemical composition of the suspension and the concentration of the powder were investigated in order to obtain a high-quality PMN-PT deposit with a target thickness of about 50 μm. The PMN-PT thick films prepared from stoichiometric and PbO-excess suspensions by sintering at 950 and 1100 °C were examined by X-ray powder-diffraction analysis and scanning electron microscopy. The highest functional response was obtained for a homogeneous, dense, crack-free PMN-PT thick film prepared from a PMN-PT suspension with excess PbO. The film was deposited at a constant voltage of 10 V and for a time of 120 s, followed by sintering at 1100 °C in a PbO-rich atmosphere. The film's properties were as follows: a dielectric permittivity ɛ of 20,250 at a Tm of 172 °C, a remanent polarization of 17 μC/cm2 and a coercive field of 5 kV/cm.