METHOD FOR PREPARATION OF IDEAL CESIUM TRIBORATE CRYSTALS FROM MULTICOMPONENT SOLUTIONS-MELTS

摘要

FIELD: chemistry. ^ SUBSTANCE: invention refers to the method for preparation of cesium triborate monocrystals with non-linear optic properties which can be used in laser technique at producing of the laser radiation frequency converters. The crystals of CsB3O5 are grown from the melt containing boron B2O3 and cesium Cs2O oxides as well as third component being the transition metal oxide (e.g. vanadium or molybdenum oxide) forming the chemical compound with cesium oxide. The working mass is prepared from cesium carbonate, boron acid or boron oxide, vanadium or molybdenum oxides. The working mass with composition lying in the fusion diagram Cs2O-B2O3 - third component in the primary crystallisation area is prepared by one of two methods. The first of them lies in solid-phase synthesis from the components or compounds generating during their destruction the mixture components. The process of working mass preparation consists in single or multifold isothermic anneal, cooling and disintegrating of the product. In multifold process the anneal temperature at every following stage is higher than at previous stage. The second method consists in mixing of starting materials in glass vessels with following portion melting in platinum crucible in the furnace at temperature 800C. For melt homogenisation the mechanical stirring is used. The crystal growth is implemented using the seed crystal and temperature decrease with rate 0.1-2C/24 hrs. The solvent usage decreases the temperature of crystal growth at 150-270C in comparison with crystal growth from stoichiometric melt and reduces in the same time the melt viscosity. This allows to avoid the Cs2O evaporation and to stabilise the process of crystal growth and to prevent formation of parasite crystals on melt surface. ^ EFFECT: possibility of crystals obtaining with high optical properties without inclusions or with insignificant inclusions is provided. ^ 4 ex, 3 cl