Piezoelectric properties of tungsten doped PZT type materials

Piezoelectric properties of four tungsten doped samples of PZT type were de termined as a function of composition. The samples were prepared by the usu al ceramic technique from raw oxide of 99.9% purity. All compositions exhib ited maximum values for the density at a sintering temperature of 1180 degr ees C with a soaking time of 4h, so that the piezoelectric properties were determined on the samples sintered at this temperature only. The results sh owed 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 rh o= 7.7 g/cm(3); dielectric constants, epsilon(T)=1410; electromechanical co upling 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 tha t tungsten doped materials are piezoelectric soft type ceramics of high qua lity that can be successfully used for manufacturing ultrasonic transducers .