CRYSTAL GROWING METHOD FROM EVAPORATING SOLUTION-MELT Russian patent published in 2020 - IPC C30B9/06 C30B9/12 C30B29/22 C30B28/02 C01B35/12 G02F1/355 

FIELD: chemistry.

SUBSTANCE: invention relates to production of crystals from volatile melts. Crystal K₇CaNd₂(B₅O₁₀)₃ is grown from the evaporating solution-melt by controlling degree of solution-melt supersaturation, at that, first, polycrystalline sample K₇CaNd₂(B₅O₁₀)₃ is prepared, which is mixed with K₂CO₃, CaF₂ and H₃BO₃ in preparation of solution-melt, in molar ratio of 1:6:6:12, heated to 900 °C is further cooled to crystallisation beginning temperature, followed by controlling degree of supersaturation of solution-melt, increasing its temperature from initial crystallisation temperature with heating rate by 0.2–2 °C/h during crystal growth. Variation of rate of increase of temperature makes it possible to effectively control supersaturation and, consequently, rate of crystallisation, which provides obtaining of optical quality from high-temperature evaporating solution-melts of crystals of optical quality.

EFFECT: as a result, a crystal of rare-earth potassium-calcium borate K₇CaNd₂(B₅O₁₀)₃ with weight of 12_2 g of size 30 × 30 × 10 mm with transparent area 5 × 5 × 5 mm, sufficient for investigation of physical properties and practical use.

1 cl, 3 dwg, 3 ex