FABRICATION OF FERROELECTRIC LEAD IRON TUNGSTATE CERAMICS VIA A 2-STAGE SOLID-STATE REACTION

Ferroelectric Pb(Fe2/3W1/3)O-3 was synthesized via a new two-stage solid-state reaction discussed in the present study. This method utilized Fe2WO6 prepared at the first-stage which subsequently reacted with a stoichiometric amount of PbO at the second stage. This process efficiently suppressed the formation of lead tungstates and liquid phases; in addition, pyrochlore phase was formed as the only intermediate compound. A substantial amount of pyrochlore phase was converted to Pb(Fe2/3W1/3)O-3 at around 710 degrees C associated with an endothermic reaction. On heating up to 750 degrees C over 99% perovskite Pb(Fe2/3W1/3)O-3 was formed, and this formation became complete at 840 degrees C. Compared with the conventional solid-state reaction, this process not only simplified the formation process, but also reduced the formation temperature of Pb(Fe-2/3W(1)/3)O-3. The crystal structure of Fe2WO6 did not significantly influence the formation mechanism; whereas, the morphology of Pb(Fe-2/3W(1)/3)O-3 was markedly affected by the grain size of Fe2WO6. By using this process, pure Pb(Fe-2/3W(1)/3)O-3 with a submicron microstructure was successfully fabricated.