DIELECTRIC-PROPERTIES OF PB(ZR,TI)O-3-DISPERSED MGO NANOCOMPOSITE

Ceramic nanocomposites with perovskite-type ferroelectric dispersoids have been studied in order to introduce ferroelectricity and piezoelec tricity into structural ceramics. First, MgO matrix/BaTiO3 dispersed c eramic nanocomposites were fabricated, but the piezoelectric coupling factor, k(p), of the nanocomposites was reduced to less than 5%. In th e present work, MgO matrix/Pb(Zr,Ti)O-3 (PZT) dispersed ceramic nanoco mposites were studied to realize ceramic nanocomposites with larger k( p) values than MgO/BaTiO3. MgO/PZT ceramic nanocomposites were success fully fabricated by a pressure-less sintering method. The MgO/PZT nano composites exhibited a D-E hysteresis loop, and the ferroelectricity o f the PZT dispersoid was confirmed. The tetragonality of the PZT dispe rsoid was decreased in comparison to that of monolithic PZT ceramics, however, the tetragonal-cubic phase transformation temperature of the PZT dispersoid was higher than that of the monolithic PZT. The decreas e in the tetragonality was correlated to the incorporation of Mg ions into the PZT dispersoid. The MgO/PZT nanocomposites exhibited piezoele ctricity after poling, and the k(p) value was about twice that of the MgO/BaTiO3 nanocomposites.