Phase Homogeneity and Segregation in PZT Powders Prepared by Thermal Decomposition of Metal–EDTA Complexes Derived from Nitrate and Chloride Solutions |
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Authors: | Hong-Wen Wang David A Hall Frank R Sale |
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Affiliation: | Materials Science Centre, University of Manchester and UMIST, Manchester, M1 7HS, United Kingdom |
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Abstract: | 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 PbCl2. 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. |
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Keywords: | lead zirconate titanate synthesis EDTA thermal decomposition nitrates |
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