Phase developments in Pb(Mg1/2W1/2)O3 and Pb(Zn1/2W1/2)O3 via B-site precursor route
2008
Lee, Woo-Joon | Kim, Nam-Kyoung
Phase formation stages of MgWO₄ and ZnWO₄ (precursor compositions for following steps) were investigated by monitoring the reactions of oxide chemicals at various temperatures. Developed phases were examined by using X-ray diffraction (XRD). Successive attempts were also conducted for Pb(Mg₁/₂W₁/₂)O₃ (PMW) and Pb(Zn₁/₂W₁/₂)O₃ (PZW) by reacting PbO with the precursor compounds. Stages of phase development in the two compositions were also analyzed. The results are compared with those of another tungsten-containing perovskite Pb(Fe₂/₃W₁/₃)O₃ (PFW) and its B-site precursor Fe₂WO₆. After PbO addition to the precursor powders, a perovskite phase formed directly (i.e., without any intermediate phases) in the case of PMW. For PbO + ½ZnWO₄, in contrast, the decomposition of ZnWO₄ and preferential reaction with PbO resulted in Pb₂WO₅ and ZnO, instead of the perovskite PZW.
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