Volatile impurities in the structure of Y3Al5O12 garnet synthesized in water fluidстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 29 апреля 2021 г.
Аннотация:The mechanism of synthesis of fine-crystalline yttrium aluminum garnet Y3Al5O12 (YAG) in sub- and supercritical conditions of water medium was studied. It was found that, under subcritical conditions, the initial oxides are hydroxylated to form yttrium hydroxide, boehmite, and agglomerates of nanoscale YAG crystals and, under supercritical conditions, the nanoscale crystals are recrystallized yielding micron YAG crystals with well-formed faces. Two-stage synthesis in sub- and supercritical water fluid allows obtaining cerium-doped YAG crystals with high photoluminescence intensity. The gas content, gas release, degassing kinetics, and water diffusion coefficients in YAG at high temperatures were determined using the method of kinetic thermodesorption mass spectrometry. Water, carbon-containing substances and oxygen play a significant role in degassing. It was concluded that the ordering of the crystal structure occurs due to the appearance of solid-phase mobility of the oxide structure and changes in the state of hydroxyl groups. Knowing the content of volatile impurities and the temperature dependence of the diffusion coefficient allows us to develop the technology of high-temperature sintering of YAG crystals in order to obtain high-quality transparent ceramics.