Browse Prior Art Database

New Perovskite and Pyrochlore Phases

IP.com Disclosure Number: IPCOM000074246D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Burns, G: AUTHOR [+2]

Abstract

New perovskite and pyrochlore phases of the type Pb(2)MSbO(6), where M= Al, Ga, In, Cr, Fe, Sc, and Y are prepared by heating mixtures of PbO, Sb(2)O(4), and the corresponding compound M2O3 in an oxygen flow at temperatures between 700-1200 degrees C. Alternatively, Sb(2)O(3) or Sb(2)O(5) may be used with the above components or any of their decomposable salts. For example, Pb(2)ScSbO(6) has been produced from the reaction: 4PbO+Sb(2)O(4)+Sc(2)O(3)+1/2 O(2) --> 2Pb(2)ScSbO(6) at 900 degrees C, followed by further homogenation and reaction at 700 degrees C and 1100 degrees C with intermediate grinding of the reaction mixture.

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New Perovskite and Pyrochlore Phases

New perovskite and pyrochlore phases of the type

Pb(2)MSbO(6), where M= Al, Ga, In, Cr, Fe, Sc, and Y are prepared by heating mixtures of PbO, Sb(2)O(4), and the corresponding compound M2O3 in an oxygen flow at temperatures between 700-1200 degrees C. Alternatively, Sb(2)O(3) or Sb(2)O(5) may be used with the above components or any of their decomposable salts. For example, Pb(2)ScSbO(6) has been produced from the reaction: 4PbO+Sb(2)O(4)+Sc(2)O(3)+1/2 O(2) --> 2Pb(2)ScSbO(6) at 900 degrees C, followed by further homogenation and reaction at 700 degrees C and 1100 degrees C with intermediate grinding of the reaction mixture.

Single crystals of these materials can be produced from the melt or with a suitable flux. A convenient method of growing these materials consists of self-fluxed growth using melt compositions containing: 70-95 mole % PbO

15-2.5 mole % Sb(2)O(4)

15-2.5 mole % M(2)O(3) and cooling the melts, contained in Pt crucibles, in air or oxygen from 1250 degrees C to 900 degrees C. The resulting crystals can be removed from the frozen melt by treatment with 10-20% HNO(3).

The table below summarizes the compounds which have been obtained and some of their properties. The stability and dielectric behavior of the Pb(2)MSbO(6) phases suggest possible uses as luminescent materials when suitably doped with activators and also as temperature insensitive, high dielectric constant bodies.

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