Flux growth of sodium beta" alumina

Abstract

A method for growing crystals of sodium beta" alumina is described. The crystals are grown by Czochralski type processes or analogous methods wherein single crystals are formed from a flux or melt. The melt is a eutectic type liquid primarily containing Na or K, (Li, Mg or other divalent element, e.g. Ni.sup.2+, Co.sup.2+, Cr.sup.2+, Fe.sup.2+, etc.) Al, in proportions to produce beta" alumina. To lower the melt temperature to where e.g. Na.sub.2 MgAl.sub.10 O.sub.17 beta" or Na.sub.2 Li.sub.1/2 Al.sub.11/2.degree.17 beta" can crystallize in its stability region (approximately less than 1700.degree. C. for the Mg version and approximately less than 1600.degree. C. for the Li version) high valent ions, which do not enter the structure, particularly V.sup.5+, Nb.sup.5+, Ta.sup.5+, Zr.sup.4+ and/or Hf.sup.4+ are added to the melt. The method has allowed the growth of single crystals of the Li-stabilized sodium and potassium varieties for the first time.

Dependencies are inferred from the claim text.