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Phase Homogeneity and Segregation in PZT Powders Prepared by Thermal Decomposition of Metal–EDTA Complexes Derived from Nitrate and Chloride Solutions
Author(s) -
Wang HongWen,
Hall David A.,
Sale Frank R.
Publication year - 1992
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.1151-2916.1992.tb05453.x
Subject(s) - lead zirconate titanate , calcination , materials science , ethylenediaminetetraacetic acid , chloride , thermal decomposition , tetragonal crystal system , differential thermal analysis , inorganic chemistry , phase (matter) , chemical engineering , mineralogy , chemistry , metallurgy , chelation , dielectric , ferroelectricity , organic chemistry , physics , optoelectronics , engineering , diffraction , optics , catalysis
Fine, homogeneous lead zirconate titanate (PZT) powders have been prepared by the thermal decompostion of metalorganic complexes derived from nitrate solutions using ethylenediaminetetraacetic acid (EDTA) as a complexing agent. It has been shown that nitrate ions accelerate the decomposition of the precursor and the crystallization of the PZT phase initiates at temperatures as low as 250°C. No intermediate phases, other than PbO, were found. The coexistence region of the rhombohedral and tetragonal phases in the sintered ceramic was found to be a little over 1 at.%. The chloride‐EDTA precursor did not form the desired PZT phase, even after calcination at 1000°C. The segregation and loss of lead was observed for this material, due to the formation and evaporation of PbCl 2 . DTA/TGA, SEM, and XRD were employed to characterize the powders. The use of TEM with nanoprobe energy dispersive X‐ray analysis (EDX), allowed the identification of the phase segregation in the chloride‐EDTA derived powder. A possible reaction mechanism for this phase segregation is suggested.