Feature of morphotropic phase boundary of (1-x)Bi Ga,Sc)O3-xPbTiO3 high temperature piezoelectric ceramics

(1-x)Bi(Ga,Sc)O3-xPbTiO3 (BGSPT) 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 (MPB), from x=0.64, y=0 to x=0.58, y=0.115; and an increasing of Curie temperature (Tc) near MPB, from 450¨_C up to 482¨_C, respectively. BGSPT ceramics, possessing the high Tc (over 480 ¨_C) and high piezoelectric coefficient (d33=274 pC/N), showed the different rule of the Curie temperature near MPB versus the end member tolerance factor (t). The mechanism of higher Tc in BGSPT system was also proposed.