Fabrication of Ferroelectric Lead Iron Tungstate Ceramics Via a Two-Stage Solid-State Reaction

摘要

Ferroelectric Pb(Fe_(2/3)W_(1/3))O_3 was synthesized via a new two-stage solid-state reaction discussed in the present study. This method utilized Fe_2WO_6 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(Fe_(2/3)W_(1/3))O_3 at around 710℃ associated with an endothermic reaction. On heating up to 750℃ over 99% perovskite Pb(Fe_(2/3)W_(1/3))O_3 was formed, and this formation became complete at 840℃. Compared with the conventional solid-state reaction, this process not only simplified the formation process, but also reduced the formation temperature of Pb(Fe_(2/3)W_(1/3))O_3. The crystal structure of Fe_2WO_6 did not significantly influence the formation mechanism; whereas, the morphology of Pb(Fe_(2/3)W_(1/3))O_3 was markedly affected by the grain size of Fe_2WO_6. By using this process, pure Pb(Fe_(2/3)W_(1/3))O_3 with a submicron microstructure was successfully fabricated.