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Sequential Combination of Constituent Oxides in the Synthesis of Pb(Fe 1/2 Nb 1/2 )O 3 by Mechanical Activation
Author(s) -
Gao Xingsen,
Xue Junmin,
Wang John,
Yu Ting,
Shen Ze Xiang
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00133.x
Subject(s) - columbite , pyrochlore , nanocrystalline material , materials science , crystallite , sintering , phase (matter) , perovskite (structure) , calcination , raman spectroscopy , oxide , mineralogy , chemical engineering , ceramic , crystallography , metallurgy , nanotechnology , chemistry , biochemistry , physics , organic chemistry , engineering , optics , catalysis
Pb(Fe 1/2 Nb 1/2 )O 3 (PFN) has been successfully synthesized via a novel mechanical activation of mixed oxides and columbite precursor consisting of lead oxide and FeNbO 4 . A nanocrystalline perovskite phase 5–15 nm in crystallite size was formed after 30 h of mechanical activation at room temperature for both types of starting materials. However, the nanocrystalline PFN phase derived from the mixed oxides of PbO, Fe 2 O 3 , and Nb 2 O 5 is unstable, and develops pyrochlore phases when calcined at 500°–900°C, while no pyrochlore phase is observed for the material derived from the columbite precursor consisting of PbO and FeNbO 5 . Different sintering behavior and dielectric properties were also observed between the two types of PFN. These differences are accounted for by the compositional inhomogeneity in the material derived from the mixed oxides, as was revealed by Raman spectroscopic studies. This suggests that mechanical activation is analogous to thermal activation, where the phase development is strongly dependent on the sequence of combining the constituent oxides.