REFRACTORY COMPOUND SHAPED CRYSTALS PRODUCING METHOD Russian patent published in 2007 - IPC C30B15/34 

FIELD: production of shaped crystals of refractory compounds such as leucosapphire, ruby, aluminum-yttrium garnet and other by growing from melt according to Stepanoff method.

SUBSTANCE: method comprises steps of evacuating melting chamber and warming heat zone; adding to melting chamber at least one inert gas; providing temperature of heat zone till melting temperature of initial raw material in crucible while filing capillary system of shaper with melt; flashing seed crystal and growing it on end of shaper; drawing crystal; tearing off crystal and cooling it. During those steps applying to melting chamber mixture of inert gases containing, mainly argon and at least helium; setting in melting chamber pressure of mixture that is less than atmospheric pressure and after growing crystal up to its complete section melting off grown part of crystal just till seed and again realizing growing procedure. Then crystal is finally grown. After cooling ready crystal the last may subjected to annealing outside melting chamber for two stages, at first in reducing carbon-containing gas medium including inert gases and then in vacuum.

EFFECT: possibility for producing high optical quality crystals with improved uniformity of optical properties, less loss of yield, lowered cost price of produced crystals.

8 cl, 2 tbl