Temperature Dependence of the Main Piezoelectric Parameters of a Nb-Li Doped Pzt Ceramic

A study was made on the temperature behavior of the main piezoelectric parameters, namely the electromechanical coupling factor k _p, the mechanical quality factor Q_m, the dielectric permittivity (real and imaginary part), the loss tangent tg and the piezoelectric charge constants d₃₃ and d₃₁ of a soft type piezoelectric material. It was evidenced that temperatures under 150degC do not influence these parameters, which means that every transducer made from this type of material may be successfully used up to this temperature. Between 150degC and 250degC the piezoelectric properties undergo more or less important changes, mainly due to the depoling effect. After that, at temperatures over 250degC, they degrade very rapidly, tending to zero