Danko O. Scientific and technological principles of the process of obtaining leucosapphire in protective gas media.

Object of investigation. Physico-chemical processes which form the basis for the obtaining of optical sapphire from alumina in reducing gaseous media by the method of horizontal oriented crystallization. Goal of investigation. Development of scientific and technological foundations for economically viable obtaining of sapphire in protective gaseous media. Methods of investigation and apparatuses. Optical and mass-spectrometry methods. Modern apparatuses, non-standard and industrial equipment for the growth of sapphire. Theoretical and practical results, novelty. Developed are scientific foundations for the growth of sapphire in reducing gaseous media. In terms of structural and optical characteristics, this material is on a par with the sapphire grown by the standard technology in high vacuum. The conditions of thermo-chemical purification of alumina in reducing medium are established and optimized, the scientific foundations of the new technological process of the obtaining of high-purity raw materialare substantiated. Established are the annealing conditions which allow to obtain pre-determined values of optical transparency and resistance of the crystals to UV-radiation. Reduction to practice. The new technologies of the obtaining of sapphire are reduced to pilot industrial production at STC "Institute for Single Crystals". Application field. Modern branches of optics and optoelectronics.