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MAGNESIUM, TITANIUM, RARE METALS, SEMICONDUCTORS
ArticleName Producing Nb2O5:Zn alloys for lithium niobate crystal growth
ArticleAuthor Masloboeva S. M., Kalinnikov V. T., Zalkind O. A., Kadyrova G. I., Kuznetsov V. Ya.
ArticleAuthorData

I. V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Centre of RAS (ICHTREMS KSC RAS)

S. M. Masloboeva, Senior Researcher, e-mail: sofia_masloboeva@mail.ru

V. T. Kalinnikov, Director

O. A. Zalkind, Researcher

G. I. Kadyrova, Researcher

V. Ya. Kuznetsov, Researcher

Abstract

Lithium niobate crystals are widely applied in integral optics, acoustic electronics and other fields. The crucial factor to be considered here is enhancing the LiNbO3 optic homogeneity and laser damage resistance. This work has focused on developing the synthesis methods for high-purity niobium (V) oxide containing trace amounts of Zn2+ ions with intended concentrations, and on studying the phase composition of products synthesized. To obtain a Nb2O5:Zn alloy, two methods of introducing the photovoltage-inactive Zn2+ cations have been investigated. By the first method, zinc oxide was added to a highly pure niobium-containing solution (re-extract) during the solvent extraction of lithium niobate, or rare-metal, processing wastes. The method can be applied in concentrating Zn2+ in Nb2O5 ~1.7 w/o. The other method involves mixing a high-purity niobium hydroxide with a nitric-acid zinc solution, with a zinc concentration sufficient to produce Nb2O5:Zn2+ of a target composition at a certain Т:Vs ratio. A flow sheet has been developed for alloying highly pure niobium hydroxide with Zn2+ ions, applicable within the entire range of studied concentrations (Nb2O5:0.3÷4.87 w/o ZnО). Optimal conditions for individual process stages have been determined. The phase composition of the Nb2O5:Zn alloys synthesized have been analyzed using IR spectroscopy and X-ray phase analysis. At Zn2+ contents in Nb2O5 of 1.9% upwards, another phase (in addition to the basic Nb2O5), having the ZnNb2O6 composition, was noted to emerge, its share increasing with growing Zn2+ concentration. There have been prepared experimental samples of niobium pentoxide for synthesizing a lithium niobate charge and growing LiNbO3 crystals with improved optic characteristics and a low photorefraction effect.

keywords Lithium niobate, niobium (V) oxide, zinc impurity, phase composition
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