A high temperature piezoelectric ceramic: (1-x)(Bi_0.9La_0.1)FeO_3-xPbTiO₃crystalline solutions

Abstract

(1-x)(Bi(0.9)La(0.1))FeO(3-x)PbTiO(3) (BLF-PT) crystalline solutions for x = 0.35, 0.37, 0.4, 0.43 and 0.45 have been prepared by the solid-state reaction method. The X-ray diffraction analysis shows that BLF-PT has a single perovskite phase with mixed tetragonal and rhombohedral phases between x = 0.4 and 0.43. The Curie temperature of BLF-PT for x = 0.4 attains 460 degrees C, which is about 80 degrees C higher than that of hard Pb(Zr,Ti)O(3) ceramics. The remnant polarization and piezoelectric constant of BLF-PT for x = 0.4 reach 38 microC/cm(2) and 112 pC/N, respectively. The planar coupling factor k(p) of BLF-PT for x = 0.4 remains stable at temperature increases of up to 360 degrees C. The impedance spectroscopy study reveals that the high temperature conduction of BLF-PT may be attributed to the motion of oxygen vacancies within the material. Our results indicate that BLF-PT is a promising candidate for high temperature applications.

Novel 0.50(Bi1-xLax)FeO3–0.35PbTiO3–0.15Bi(Zn1/2Ti1/2)O3Piezoelectric Ceramics for High Temperature High Frequency Filters

“…By the end, it is of interest to note that the previous experiments usually adopted heavy La substitution more than 5 at. % in order to obtain high piezoelectric response while the Curie temperature of the (Bi,La)FeO 3 -PbTiO 3 system decreases remarkably below 450 C. 32,41) In Table I, we summarized those obtained piezoelectric properties of 0.50BL x F-0.35PT-0.15BZT (x ¼ 0:05 and 0.08) ceramics with T C above 450 C, together with those of 0.95PT-0.05BZT, 3 wt % La doped 0.6BF-0.4PT, commercial MLT and PZT-6B ceramics. Compared with the 0.95PT-0.05BZT and 3 wt % La doped 0.6BF-0.4PT systems, the 0.50BL x F-0.35PT-0.15BZT (x ¼ 0:05{0:08) ceramics exhibit not only good high temperature piezoelectric properties but also better mechanical properties, which can be guaranteed by the features of structural phase boundary and the nearzero thermal expansion coefficient.…”