Goh, Gregory K. L. and Lange, Fred F. and Haile, Sossina M. and Levi, Carlos G. (2003) Hydrothermal synthesis of KNbO_3 and NaNbO_3 powders. Journal of Materials Research, 18 (2). pp. 338-345. ISSN 0884-2914 http://resolver.caltech.edu/CaltechAUTHORS:20111005-135037470
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Orthorhombic KNbO_3 and NaNbO_3 powders were hydrothermally synthesized in KOH and NaOH solutions (6.7–15 M) at 150 and 200 °C. An intermediate hexaniobate species formed first before eventually converting to the perovskite phase. For synthesis in KOH solutions, the stability of the intermediate hexaniobate ion increased with decreasing KOH concentrations and temperatures. This led to significant variations in the induction periods and accounted for the large disparity in the mass of recovered powder for different processing parameters. It is also believed that protons were incorporated in the lattice of the as-synthesized KNbO_3 powders as water molecules and hydroxyl ions.
|Additional Information:||© 2003 Materials Research Society. Received 22 July 2002; accepted 28 October 2002. This work was supported by the Materials Research Laboratory program of the National Science Foundation under Award No. DMR00-80034. G.K.L. Goh acknowledges the Institute of Materials Research and Engineering (Singapore) for the provision of a research scholarship. Dr. Joon Hwan Choi is thanked for the TEM results while Dr. Sonjong Hwang of the California Institute of Technology is thanked for collecting the ^1H MAS NMR data.|
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|Deposited By:||Tony Diaz|
|Deposited On:||06 Oct 2011 15:51|
|Last Modified:||26 Dec 2012 14:01|
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