A new method for the preparation of compositionally homogeneous and pyrochlore-free solid solution of Pb(Mg1/3Ta2/3)O3-Pb(Yb1/2Ta1/2)O3 system

A new method was developed for the synthesis of solid solution of Pb(Mg1/3Ta2/3)O-3-Pb(Yb1/2Ta1/2)O-3 (PMYT) system having no compositional fluctuation. This method is a combination of wet and dry processes. At the first stage, the homogeneous mixture of MgO and Yb2O3 (MY-powder) was prepared through a wet process. Then the dry process was performed in a solid-state reaction among the MY-powder, PbO, and Ta2O5 to obtain PMYT. The powder X-ray diffraction analysis revealed that PMYT prepared by this wet-dry combination method had practically no compositional fluctuation; it was difficult to eliminate the compositional fluctuation through the conventional dry method. Another advantage of the wet-dry combination method is that pyrochlore-free PMYT can be obtained. This is due to the high reactivity of the MY-powder. In the combination method, the wet process has to be applied to only two species of the B-site cations. Thus, it can be used for the preparation of many A(a+)(BIxb+BIIc+ (1-x))(f(x))BIII1-f(x)d+O32- (f(x) = (6 - a - d)/{bx + c(1 - x) - d}, and b < c < 6 - a < d, or b > c > 6 - a > d)-type solid solutions effectively. (C) 2000 Elsevier Science Ltd.