Feature of morphotropic phase boundary of yBiGaO3-(1-x-y)BiScO3-xPbTiO3 high-temperature piezoelectric ceramics

yBiGaO(3)-(1-x-y)BiScO3-xPbTiO(3) (BGSPT) ternary piezoelectric ceramics were fabricated by using conventional mixed oxide ceramic processing. It was found that the introduction of BiGaO3 into BiScO3-PbTiO3 system would cause a shift of morphotropic phase boundaries (MPBs), from x=0.64, y=0 to x=0.56, y=0.155; and an increase of Curie temperature (T-C) near MPB, from 450 up to 494 degrees C, respectively. BGSPT ceramics possessed higher T-C (similar to 494 degrees C) and high piezoelectric coefficient (d(33)similar to 180 pC/N), and showed the different rule of the Curie temperature near MPB versus the end member tolerance factor (t). The mechanism of higher T-C in BGSPT system was also proposed. (C) 2008 American Institute of Physics.