Influence of sintering temperature on the properties of high Tc bismuth layer structure ceramics

Bismuth layer structure Ca-0.82(NaCe)(0.09)Bi4Ti4O15 piezoelectric ceramics were prepared by the conventional ceramic technique. Sintering characteristic of Ca-0.82(NaCe)(0.09)Bi4Ti4O15 was discussed. The X-ray powder diffraction pattern showed a single phase of bismuth oxide layer structure having general formula (Bi2O2)(2+) (A(m) (-) 1BmO3m + (1))(2-) with m = 4. Scanning electron microscope (SEM) micrographs of the natural surface of ceramic samples indicated that the anisotropy of growth of grains becomes stronger with the increase in the sintering temperature. With the increase in the sintering temperature. the resistivity and piezoelectric constant d(33) increased to a maximum value and then decreased. but the dielectric constant epsilon(33)(T)/epsilon(0) decreased. The Curie temperature and the capacitance temperature stability of the ceramics were improved with the increase in the density. (C) 2002 Elsevier Science B.V. All rights reserved.