Electrophoretic Deposition and the Electrical Properties of the PNN-PZT Thick Films

0.3Pb(Ni1/3Nb2/3)O3-0.7Pb(Zr,Ti)O3 (PNN-PZT) thick films (10-40| ) were prepared by electrophoretic deposition method on Al2O3/Pt plates and Pt metallic foils. The effect of pH value on the stability of PNN-PZT suspensions was studied by measuring the zeta potential. The relationship among the deposition voltage, time and the quality of PNN-PZT films were investigated. When the pH value is in the range of 3.5-5.5, the suspension with the 2wt% PEG is stable. When the deposited voltage and time are 21V and 5min, respectively, the PNN-PZT thick films deposited on the Pt foil are uniform and free of crack. After sintering at 1200 or 30min, the PNN-PZT films with high density are obtained. The PNNa2PZT thick films show the high ferroelectric and dielectric properties with the remnant polarization of 20.8| /cm2 and the loss tangent of about 3.2% at 1 kHz. And the frequency dependences of the dielectric spectra of the PNN-PZT thick films show the relaxor property. The piezoelectric constant calculated from the Sa2V curve tested using the SPM is 67pm/V.