METHOD OF GROWING MONOCRYSTALS 57FEBO3 OF HIGH STRUCTURAL PERFECTION Russian patent published in 2021 - IPC C30B9/04 C30B9/12 C30B29/22 C30B29/64 

FIELD: chemistry.

SUBSTANCE: invention relates to production of monocrystals ⁵⁷FeBO₃ of high structural perfection for use as monochromators during experiments on nuclear resonance scattering using synchrotron radiation. Method is carried out as following. Charge containing ⁵⁷Fe₂O₃ - 4.9 wt. %, B₂O₃ - 58.3 wt. %, PbO - 25.0 wt. %, PbF₂ - 11.8 wt. %, is deposited in a platinum crucible at 870°Then crucible with melt is successively covered with perforated platinum foil and crucible-cover. Crucibles are packed in refractory brick container and placed in gradientless area of shaft resistance furnace. Temperature is raised to 900-950°C for 6 hours to melt component and held for 20-25 hours. Then cyclically (2-3 cycles) is cooled down to 800-830°C for 20-30 minutes, maintained at this temperature for 4-6 hours, again heated to 900-950°C for 20-30 minutes and held for 10-12 hours after which temperature is sharply reduced for 15 minutes to 810-820°C and then smoothly cooled at rate of 0.1-0.2°C/h to temperature 760-790°C, after which container is removed from furnace, smoothly turned around horizontal axis and returned back, providing drainage of solution-melt into crucible-cover. Furnace is cooled to 500°C for 4-6 hours, and then switched off, allowing to cool to room temperature. Crucibles are extracted and opened. Crystals, in the form of hexagonal plates, are found on perforated foil and walls of the main crucible.

EFFECT: technical result consists in enabling production of well-developed monocrystalline ⁵⁷FeBO₃ plates of high structural perfection, wherein no side crystalline phases are formed (Fe₃BO₆ and α-Fe₂O₃).

1 cl, 2 dwg, 3 ex