A comparison of the properties of (1-x)PMN-xPT ceramics near the morphotropic phase boundary prepared by sol-gel and columbite precursor methods

Ceramic lead magnesium niobate-lead titanate ((1-x)PMN-xPT) of different compositions was prepared using sol-gel and columbite precursor methods. This study covers compositions ranging from 0.72PMN-0.28PT to 0.50PMN-0.50PT, focusing on (1-x)PMN-xPT compositions that exhibit piezoelectric behavior. X-ray diffraction is used to show that the (1-x)PMN-xPT system has a compositionally wide two-phase region and that 0.655PMN-0.345PT is the morphotropic phase boundary (MPB) composition. Microstructures of ceramics prepared by the two different methods are presented. Electromechanical property evaluation shows that the optimal piezoelectric properties (d/sub 33/=720 pC/N, K=5400, k/sub p/=62%, and k/sub t/=46%) are obtained at the MPB composition.