Piezoelectric properties of pure and (Nb5+ + Fe3+) doped PZT ceramics

This work evaluates the effect caused by the addition of Fe3+ and Nb5+ ions on the piezoelectric properties of lead zirconate titanate. Three compounds were obtained using the conventional method of mixture of oxides. The oxides were calcined at 850 °C and after that submitted to a uniaxial pressure of 70 MPa and an isostatic pressure of 200 MPa. Subsequently, the samples were sintered at 1200 and 1250 °C for 3.5 h. The surfaces were metalized and polarized in order to determine the piezoelectric properties. High concentration of dopants in lead zirconate titanate yielded high values of dielectric constant (K33T) and specific mass. Moreover, there was an increase of the factor of electromechanical coupling (Kp) when compared to the pure PZT ceramics, associated with a decrease in the mechanic quality factor.