Synthesis and Characterization of PZN-PT Materials

Abstract

Compositions near the morphotropic boundary in the Pb(Zn1/3Nb2/3)03-PbTiO3 system were synthesized from the melt and analyzed. Up to four mol% variation in the PbTi03 component was found in meltsynthesized crystals, and both rhombohedral and tetragonal phases coexist in the region n ear the morphotropic boundary defined by earlier researchers. Powders made from the melt-synthesized crystals were used to make ceramics. Compositions of individual grains in the ceramics are the same as those of the starting powders, and up to 85% of the perovskite phase remains after firing. Individual grains of ZnO appear at grain boundaries, w ith or without a lead-rich phase, depending on the synthesis conditions. A pyrochlore phase forms that is not generally a ssociated with PbO or ZnO phases and is more concentrated n ear the outer surfaces of the ceramic pellets. Electrical properties are presented and possible approaches to increasing the amount of perovskite are discussed. INTRODUCT ION