Transparent Ceramics Research Center, SICCAS
Key Laboratory of Transparent Opto-fuctional Inorganic Materials, CAS
EFFECT OF POWDER ANNEALING ON EVOLUTION OF PHASE COMPOSITION AND MICROSTRUCTURE DURING SINTERING OF TRANSPARENT OXIDE CERAMICS
Dr. Roman Yavetskiy
Institute for Single Crystals, NAS of Ukraine
时间：6月12日 （星期二）10:45 AM
Yttrium aluminum garnet and yttria ceramics (Y3Al5O12 and Y2O3) are prospective model objects of the modern condensed matter physics to establish correlation of powder characteristics on densification and microstructure evolution during solid-state sintering. Besides, Y3Al5O12:Nd is one of the most useful material of modern quantum electronics and laser engineering. This work is devoted to study effect of the powder parameters, green body mesostructure on the evolution of phase composition and microstructure during sintering of transparent oxide ceramics.
Influence of the green bodies annealing on optical properties as well as on the laser performance of Y3Al5O12:Nd ceramics has been investigated. The mercury porometry, XRD, HRTEM, laser confocal scanning microscopy, optical spectroscopy have been used to study green bodies and sintered ceramics. It has been shown that phase transformations with positive volume change observed for green body annealed at 1000°C may effectively decrease the free energy of the powder system thus preventing achievement the “pore-free” state of ceramics. The optimal annealing temperature of green bodies has been determined. The laser characteristics of Y3Al5O12:Nd 1 at% ceramics depending the annealing temperature of green body have been determined under diode pumping. The highest slope efficiency of 67% has been obtained.
The effect of powder annealing on evolution of phase composition during sintering of transparent (Y1-x-yLaxYby)2O3 ceramics has been studied and discussed. The mechanism of (Y1-x-yLaxYby)2O3 solid solution formation has been proposed.
Roman Yavetskiy was born on April 13, 1977, in Kharkiv, Ukraine. He graduated from National Technical University “Kharkiv Polytechnic Institute”. In 2006 he defended Ph.D. Thesis in Physics and Mathematics at Institute for Single Crystals, NAS of Ukraine (specialty Solid State Physics). In 2014 he obtained the Fellowship for Young International Scientists of Chinese Academy of Sciences (Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS)). In 2017 he becomes Doctor of Sciences in Engineering (specialty Material Sciences), Institute for Single Crystals, NAS of Ukraine.
He works at Institute for Single Crystals, NAS of Ukraine, from 2000. Now he is Head of Department of Crystalline Materials of Complex Crystalline Compounds. Research activity of Roman Yavetskiy is devoted to optimization of the structure, morphology and optical properties of the transparent ceramics for photonics and laser technique; study of the densification processes and phase transitions occurring during consolidation of oxide nanopowders; identification the structural-phase state of oxide optical ceramics, (rare-earth doped Y2O3, Lu2O3, Y3Al5O12, etc.); consolidation of nanoceramics via transformation-assisted route.
He was Principal Investigator of a number of domestic Projects, as well as bilateral R&D Projects (Ukrainian-Russian, Ukrainian-Romanian, and Ukrainian-Chinese). He authored 75 papers published in International journals included in SCOPUS database.