METHOD FOR GROWING SILVER HALIDE SINGLE CRYSTALS BASED ON SOLID SOLUTIONS OF AgBrI - AgCl SYSTEM (VARIANTS) Russian patent published in 2023 - IPC C30B11/02 C30B29/12 C30B33/02 

FIELD: optical materials.

SUBSTANCE: invention can be used in the manufacture of optical materials that are resistant to ionizing radiation, which are plastic, non-toxic, non-hygroscopic and highly transparent at the level of theoretical values in the visible, infrared and terahertz ranges, intended for laser technology, medicine, IR fiber and terahertz optics, optoelectronics and photonics. First, using the basic hydrochemical method of thermozone crystallization, a mixture is obtained based on salts of single-phase solid solutions with a purity of cationic impurities of 99.9999 wt.%. The mixture is then loaded into a Pyrex glass ampoule with a hole in the conical part and placed above the ampoule for growing single crystals. Both ampoules are placed in the upper part of the installation, which implements the vertical Bridgman method, where the charge is melted, the melt is dripped into the ampoule for growing single crystals, kept for an hour and the ampoule is moved to the lower zone with a reduced temperature at a speed of 0.5–1.0 mm/h for the formation of single crystals based on a single-phase solid solution. To form a perfect structure of a single crystal based on a single-phase solid solution of the cubic system of structural type NaCl, annealing is carried out in the installation at 100°C for 20 hours. The method of growing silver halide single crystals based on solid solutions of the AgBr_0.7I_0.3 – AgCl system is carried out in two variants. According to the first option, a high-purity dispersed single-phase charge is obtained based on a solid solution of AgBr_0.7I_0.3, additionally containing a solid solution of AgCl_0.18Br_0.58I_0.24, at the ratio, mol.%: AgBr_0.7I_0.3 98.0–82.0; AgCl_0.18Br_0.58I_0.24 2.0–18.0, melted at 410–430°C, and movement at the above speed is carried out to the lower zone of the installation, which has a temperature of 290–310°C. According to the second option, a high-purity dispersed single-phase charge is obtained based on a solid solution of AgCl, additionally containing a solid solution of AgCl_0.73Br_0.19I_0.08, at the ratio, mol.%: AgCl 98.0–73.0; AgCl_0.73Br_0.19I_0.08 2.0–27.0, melted at 430–490°C, and movement at the above speed is carried out to the lower zone of the installation, which has a temperature of 290–350°C. The phase diagram of the AgBr_0.7I_0.3 - AgCl system was studied for the first time.

EFFECT: resulting silver halide single crystals are resistant to ionizing radiation and transparent in the spectral range from 0.4 to 50.0 microns without absorption windows due to the content of crystals of heavy molecular weight silver iodide in their composition, they have high plasticity and resistance to moisture; products based on them are non-toxic.

2 cl, 1 dwg, 3 ex