Effects of Li/sub 2/CO/sub 3/ and Bi/sub 2/O/sub 3/ additives on sintering temperature and piezoelectric properties of PNIN-PCW-PZT ceramics for multilayer piezoelectric transformer

In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, PCW-PMN-PZT ceramics doped with Li/sub 2/CO/sub 3/, Bi/sub 2/O/sub 3/ and CuO as sintering aids were manufactured, and their microstructural, dielectric and piezoelectric properties were investigated. When the only CuO was added, specimens could not be sintered below 980/spl deg/C. However, when Li/sub 2/CO/sub 3/ and Bi/sub 2/O/sub 3/ were added, specimens could be sintered below 980/spl deg/C. Li/sub 2/CO/sub 3/ and Bi/sub 2/O/sub 3/ addition were proved to lower sintering temperature of piezoelectric ceramics due to the effect of Li/sub 2/O-Bi/sub 2/O/sub 3/ liquid phase. Li/sub 2/CO/sub 3/ and Bi/sub 2/O/sub 3/ added specimens showed higher piezoelectric properties than those of the only CuO added specimens. At 0.2wt% Li/sub 2/CO/sub 3/ and 0.3wt% Bi/sub 2/O/sub 3/ added specimen sintered at 920/spl deg/C, the dielectric constant (/spl epsi//sub r/) of 1457, electromechanical coupling factor (k/sub p/) of 0.56 and mechanical quality factor (Q/sub m/) of 1000 were shown, respectively. These values are suitable for multilayer piezoelectric transformer application.