METHOD OF PRODUCING MIXTURE OF LITHIUM NIOBATE FOR GROWING MONOCRYSTALS

摘要

FIELD: chemistry.SUBSTANCE: invention relates to production of boron-doped lithium niobate mixture, which can be used for growing optically homogeneous lithium niobate monocrystals, as well as non-porous piezoelectric ceramics. Niobium hydroxide is precipitated from a fluoride niobium-containing solution using ammonia solution, niobium hydroxide precipitate is separated, washed with deionised water and dried to residual moisture content of 60-70 %. Boron dopant in form of a solution of boric acid is mixed with dried niobium hydroxide precipitate to form a suspension. Content of boron in boric acid is adjusted to ensuring its content in mixture of 0.05-1.5 wt%. Boric acid solution is mixed with niobium hydroxide precipitate according to proposed ratio. Obtained suspension is evaporated to dryness at temperature of 110-140 °C. Formed precipitate of boron-containing niobium hydroxide is calcined at temperature of 950-1000 °C. Obtained boron-doped powdered niobium pentoxide is mixed with lithium carbonate and subjected to thermal treatment at temperature 1100-1200 °C to produce a mixture of lithium niobate.EFFECT: invention enables to obtain a mixture of lithium niobate with a stable composition in a given range (0 5/100-1 5/10 wt%) of concentration of boron dopant with simultaneous reduction of boron losses.4 cl, 4 ex