METHOD FOR PRODUCING CRYSTALS OF ALLOYS OF FLUORITE SOLID SOLUTIONS М1-X М'XF2, WHERE M = CA, SR, BA; M' = PB, CdD, X IS MOLE FRACTION OF VOLATILE COMPONENT M'F2 (VARIANTS) Russian patent published in 2021 - IPC C30B11/04 C30B28/06 C30B29/12 C30B29/52 C22C1/02 G02B1/02 

FIELD: chemical engineering.

SUBSTANCE: invention relates to technology of producing fluoride crystals which are widely used in optics, photonics, high-energy physics. One of the variants is the method for producing crystals of fluoride solid solutions М_1-xM'_xF₂ where М=Са, Sr, Ва; М'=Pb, Cd where 0<х<1 and is a mole fraction of volatile component М'F₂ including vertical directed crystallization of components in a fluorinating atmosphere. wherein components MF₂ and М'F₂ are pre-melted in a fluorinating atmosphere, said components are ground, then the quantity (1-x) of MF₂ component, determined by the stoichiometry of the grown solid solution M_1-xM'_xF_2, is placed in melting pot 3 in the body 1 of growth furnace containing a heat unit 2 and the necessary quantity of М'F₂ component, determined by its mole fraction x, is placed in the form of granules in a dosing device 5 which is vacuumed on the top flange of the furnace’s growth chamber, the furnace is then vacuumed to a residual pressure level of 5⋅10^-4-10^-5 mm hg, filled with He and CF₄ gas mixturein a quantity of 5-10 vol %, heated to a temperature above the melting point of MF₂ by 20-50°, hold the melt 4 for 60-120 min for fluoration and homogenization and then, once or as a portion thereof, the granules of the component or mixture of components of MF₂ are introduced into the melt 4 via a metering device, and then the melting pot 3 with melt 4 is moved into the cold zone of the furnace at a rate of 2-5 mm/h, the melting pot is cooled after crystallization of the melt at a rate of 100-200°C/h to room temperature and the crystal of the fluoride solid solution М_1-xM'_xF₂ is extracted. Another variant is a method for producing fluoride solutions М_1-xM'_xF₂ in the form of alloys where М=Са, Sr, Ва; М'=Pb, Cd where 0<х<1 and is a mole fraction of volatile component М'F₂ which consists in pre-melting in a fluorating atmosphere of MF₂ and М'F₂ components, said components are ground, the quantity (1-x) of MF₂ component, determined by the stoichiometry of the grown solid solution М_1-xM'_xF₂ is then placed in melting pot 3 in a growing furnace and the necessary quantity of the М'F₂ component determined by its mole fractions x is placed in a form of granules in a dosing device 5 which is vacuumed on the top flange of the furnace’s growth chamber, whereupon the furnace is vacuumed to a residual pressure level of 5⋅10^-4-10^-5 mm hg, the furnace is filled with a mixture of gases He and CF₄ in quantities of 5-10 vol%, is heated to a temperature above the melting point of MF₂ by 20-50°, the melt 4 is held for 60-120 min for fluorination and homogenization and then , once or as a portion thereof, the granules of the component or mixture of components of M'F₂ are introduced into the melt 4 via a metering device until the М'F₂ component is fully consumed in the metering device the temperature in the furnace is reduced by 100-150° below the melting point of the solid solution М_1-xM'_xF₂, thermostating the melt for 30-60 minutes, then cooling at a rate of 100-200°C/h to room temperature and extracting the homogeneous polycrystalline alloy М_1-xM'_xF₂.

EFFECT: invention enables producing high-quality volumetric fluoride crystals with a uniform or specified gradient distribution of the volatile component along the length of the crystals.

6 cl, 4 dwg, 2 ex