Hydrothermal phase equilibria studies in Ln2O3---H2O systems and synthesis of cubic lanthanide oxides

Viswanathiaha, MN and Tareena, JAK and Kutty, TRN (1980) Hydrothermal phase equilibria studies in Ln2O3---H2O systems and synthesis of cubic lanthanide oxides. In: Materials Research Bulletin, 15, Is (7). pp. 855-859.

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Abstract

Phase diagrams for the systems Ln2O3---H2O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) studied at 5000 to 10,000 psi and temperature range of 200–900°C, show that Ln(OH)3 hexagonal and LnOOH monoclinic are the only stable phases from Nd to Ho. The cubic oxide phase (C---Ln2O3) is stable for systems of Er, Tm, Yb and Lu, with no evidence of its equilibrium in the systems of lighter lanthanides. Using strong acids, HNO3 and HCOOH, as mineralisers the cubic oxides could be stabilised from Eu down to Lu. Solid solution phases of CeO2---Y2O3 and Eu2O3---Y2O3 have also been synthesised with HNO3 as mineraliser, since these compounds have promising use as solid electrolyte and phosphor materials respectively.

Item Type:	Journal Article
Publication:	Materials Research Bulletin
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Publisher.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	12 Aug 2009 10:19
Last Modified:	19 Sep 2010 05:36
URI:	http://eprints.iisc.ac.in/id/eprint/21319

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