Piezoelectric properties of tungsten doped PZT type materials

Piezoelectric properties of four tungsten doped samples of PZT type were determined as a function of composition. The samples were prepared by the usual ceramic technique from raw oxide of 99.9% purity. All compositions exhibited maximum values for the density at a sintering temperature of 1180 degrees C with a soaking time of 4h, so that the piezoelectric properties were determined on the samples sintered at this temperature only. The results showed that the piezoelectric properties were not drastically modified by the doping level, but dopings higher than 5% at. sightly alter the properties. The best values obtained for the piezoelectric parameters were: density rho= 7.7 g/cm(3); dielectric constants, epsilon(T)=1410; electromechanical coupling factors, k(p) = 0.63, and k(T) = 0.55; mechanical quality factor Q(m) approximate to 90; piezoelectric voltage constant d(33) = 470.10(-12) m/V; piezoelectric charge constant g33 = 25.10(-3) Vm/N. These values show that tungsten doped materials are piezoelectric soft type ceramics of high quality that can be successfully used for manufacturing ultrasonic transducers.