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Alkali Alkaline Earth Niobates of the Type AA'NbO(4)

IP.com Disclosure Number: IPCOM000090718D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Burns, G: AUTHOR [+3]

Abstract

Alkali-Alkaline Earth Niobates of the type AA'NbO(4), where A is an alkali cation such as K, Na, Rb or Li and A' is an alkaline earth cation such as Ba, Sr or Ca, or another divalent cation such as Pb are prepared as single-phase materials. This is effected by heating mixtures of alkali and alkaline earth oxides, nitrates, oxalates or carbonates with niobium pentoxide in air at temperatures between 800-1600 degrees C. For example, NaBaNbO(4) is prepared by reacting Na(2)CO(3) and Nb(2)O(5) in a molar ratio of 1:2:1 in air at 900 degrees C. The mixture is cooled to room temperature, reground and refired under the above conditions to insure complete reaction of the starting materials.

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Alkali Alkaline Earth Niobates of the Type AA'NbO(4)

Alkali-Alkaline Earth Niobates of the type AA'NbO(4), where A is an alkali cation such as K, Na, Rb or Li and A' is an alkaline earth cation such as Ba, Sr or Ca, or another divalent cation such as Pb are prepared as single-phase materials. This is effected by heating mixtures of alkali and alkaline earth oxides, nitrates, oxalates or carbonates with niobium pentoxide in air at temperatures between 800-1600 degrees C. For example, NaBaNbO(4) is prepared by reacting Na(2)CO(3) and Nb(2)O(5) in a molar ratio of 1:2:1 in air at 900 degrees
C. The mixture is cooled to room temperature, reground and refired under the above conditions to insure complete reaction of the starting materials.

Another method of preparation consists of reacting an alkali metal niobate ANbO(3) with an alkaline earth oxide or carbonate, i.e., A'O or A'CO(3), in the molar ratio 1:1 under the above conditions. Single crystals of the above compositions can be grown from stoichiometric melts or melts within the primary ternary phase field. The solid compositions obtained by solid-state reaction or crystallization from the liquid can be varied over small ranges from the stoichiometric A(2)O:A'O:Nb(2)O(5) ratio of 1:2:1.

These compositions can be suitable for dielectric ceramic applications, electro-optic devices, or as laser hosts or luminescent materials when suitably doped.

Composition Dielectric Constant at 25 degrees C Form NaCaNbO(4) 36 sint...