Investigation of PNN-PZT Thick Films Fabricated by Electrophoretic Deposition

0.2Pb(Ni1/3Nb2/3)O3-(0.8−x)PbTiO3-xPbZrO3 (PNN-PZT) dense piezoelectric thick films with the thickness of about 50 μm were fabricated by electrophoretic deposition(EPD) on Pt wire. Effects of different dispersants to the Zeta potential of the suspension and the microstructures of the PNN-PZT thick films were evaluated. The results shows that suspension with polyethyleneglycol 10000 is more stable than the suspension with polyethyleneglycol 6000, and the thick films deposited from suspension with polyethyleneglycol 10000 is more denser. The effects of different dispersants on the stability of the suspension and the influences of different deposition methods on the microstructures of the thick films were discussed. The result shows that dense thick films can be fabricated by stepwise deposition. The effect of different sintering temperatures to the dielectric constant and the dielectric loss of PNN-PZT thick films at room temperature were investigated. The dielectric constant and the dielectric loss at room temperature of the PNN-PZT thick film sintered at 1180°C for 30 min are 988 and 3.7% respectively. The electric induced displacement (E-D) curve and hysteresis loop of the PNN-PZT thick films were measured. The effective piezoelectric constant and the residual polarization of the PNN-PZT films are 90 pm/V and 6.00 kV/cm, respectively.