High temperature “Hard” piezoelectric ceramics of BiScO3-PbTiO3-Pb(Nb, Mn)O3 with Fe2O3 addition

“Hard” piezoelectric materials of Fe modified 0.37BiScO
₃
-0.6PbTiO
₃
-0.03Pb(Mn
_1/3
Nb
_2/3
)O
₃
(BS-PT-PMN-Fe) ceramics were prepared by traditional solid state reaction method. X-ray diffraction (XRD) analysis revealed that BS-PT-PMN-Fe ceramics showed single perovskite structure with dominant tetragonal phase, and the c/a ratios was enlarged with Fe content. The grain size of BS-PT-PMN-Fe ceramics decreased obviously from 25 to 1 μm with the increase of Fe content from 0 to 3 mol%. The dielectric and piezoelectric properties of BS-PT-PMN-Fe ceramics with 2 mol% Fe addition are as follows: ε = 600, tanδ = 0.008, d
₃₃
= 240, Q
_m
= 500, and k
_p
= 0.38, which were comparable to those of PZT-4 traditional “hard” piezoelectric ceramics. Both piezoelectric and dielectric properties were stable from room temperature up to 400 °C, about 250 °C higher than those of conventional PZT piezoelectric ceramics. In addition, the temperature coefficient of resonance frequency (TCF) of ceramics with 3 mol% Fe addition was -21 ppm/°C, which is one tenth that of PZT ceramics.