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A. V. Maryashkin, Yu. D. Ivakin, M. N. Danchevskaya, G. P. Muravieva, M. N. Kirikova
Corundum doped with cerium
during synthesis in water fluid
Abstract
In paper the
properties of corundum, doped with cerium during synthesis in supercritical
water are investigated. The synthesis of fine crystalline corundum has
performed
in water fluid at T=415°C and P=21.6–31.6 MPa with cerium in interval 0.001 –
0.25 mass.% in reaction medium. Kinetics and mechanism of corundum (a-Al2O3) formation from
Al(OH)3 (hydrargillite), as
well as the incorporation of cerium ions into structure of corundum were
investigated. The hydrargillite was transformed into Ce-doped boehmite and then
into the powder of single crystals (20 – 50 mm) of doped corundum. The size of corundum crystals was growing with an increase of pressure and content of cerium
ions in reaction medium. The luminescent emission of cerium ions in corundum
(at 370 nm) is increased with the fluid pressure during synthesis. The heating
in vacuum at 1400°C leads to decrease of the luminescence intensity. It is
concluded that the cerium ions generate in the structures of boehmite and
corundum the optically active complex with hydroxyl groups and oxygen
vacancies.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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