半化学法制备PMW-PNN-PT粉体的反应机理研究

Reaction Mechanism of Perovskite PMW-PNN-PT Phase Prepared by Semichemical Method

The mechanism of perovskite 0.1Pb(Mg1/2W1/2)O3-0.6Pb(Ni1/3Nb2/3)O3-0.3PbTiO3 (abbreviated PMW-PNN-PT) phase formation by Semichemical Method has been studied. The precursors were prepared by adding aqueous solution of Mg(Ac)2 and Ni(AC)2 rather than solid MgO and NiO to the alcoholic slurry of PbO, WO3, Nb2O5 and TiO2. The TG-DTG and DSC of the precursors and XRD analysis of the powders at various calcination temperature showed that the mechanism of this method was different from that of the conventional mixed oxide method. The aqueous Mg(Ac)2 and Ni(Ac)2 reacted with PbO to form basic lead acetate, basic magnesium acetate and basic nickel acetate and so on. With the increase of calcination temperature these basic salt decomposed to form nascent PbO, MgO and NiO, which improved the reactivity and distribution of PbO, MgO and NiO. In addition, the formation of PbWO4 and pyrochlore phase Pb3Nb2O8 in the process was in favor of the pervoskite PMW-PNN-PT phase formation. At the calcining temperature of 850 ℃, the perovskite phase reached 98%.

The mechanism of perovskite 0.1Pb(Mg1/2W1/2)O-3-0.6Pb(Ni1/3Nb2/3)O-3-0.3PbTiO(3) (abbreviated PMW-PNN-PT) phase formation by Semichemical Method has been studied. The precursors were prepared by adding aqueous solution of Mg(Ac)(2) and Ni(AC)(2) rather than solid MgO and NiO to the alcoholic slurry of PbO, WO3, Nb2O5 and TiO2. The TG-DTG and DSC of the precursors and XRD analysis of the powders at various calcination temperature showed that the mechanism of this method was different from that of the conventional mixed oxide method. The aqueous Mg(Ac)(2) and Ni(Ac)(2) reacted with PbO to form basic lead acetate, basic magnesium acetate and basic nickel acetate and so on. With the increase of calcination temperature these basic salt decomposed to form nascent PbO, MgO and NIO, which improved the reactivity and distribution of PbO, MgO and NiO. In addition, the formation of PbWO4 and pyrochlore phase Pb3Nb2O8 in the process was in favor of the pervoskite PMW-PNN-PT phase formation. At the calcining temperature of 850 degrees C, the perovskite phase reached 98%.