Seeding effect in the formation of Pb(Fe2/3W1/3)O-3 via mechanical activation of mixed oxides

Twenty hours of mechanical activation of PbO, Fe2O3 and WO3 at room tempera ture led to the occurrence of PbWO4 and PbFe2WO6.5, which are the common tr ansitional phases that are formed during the conventional solid state react ion at elevated temperatures. In addition, the perovskite Pb(Fe2/3W1/3)O-3 (PFW) phase cannot be synthesized when PbO is mechanically activated with p re-reacted Fe2WO6. In contrast, adding 0.4 mole of preformed PFW seeding to the constituent oxides resulted in the suppression of transitional PbWO4 a nd PbFe2WO6.5 phases during mechanical activation. The PFW seeding also has a strong effect on the types of transitional phases involved when the acti vated compositions are subjected to an increasing calcination temperature. (C) 2000 Elsevier Science B.V. All rights reserved.