Piezoelectric and pyroelectric properties of (K_0.5Na _0.5)_1-x (Nb_1-yTa_y)O₃ ceramics

A worldwide effort is underway to remove lead from many commercial products. Most ferroelectric ceramics contain lead, principally those based on lead-zirconate-titanate solid solutions. Recently a new non-lead containing composition series has been developed by Saito et al. These are alkaline niobate based materials with the composition (K 0.5 Na 0.5 ) 1 - x (Nb 1 - y Ta y )O 3 . The d 33 piezoelectric coefficient of these materials is comparable to that of PZT4. Measurements of many of the properties of these new materials are reported here for the first time. These include piezoelectric coefficients, permittivity and loss tangent, and coercive field and remanent polarization. Special emphasis is placed on the pyroelectric studies.