Synthesis of corundum doped with cerium in supercritical water fluid

Autor: Danchevskaya Marina N, G. P. Murav’eva, A. V. Maryashkin, M. N. Kirikova, Yu. D. Ivakin
Rok vydání: 2011
Předmět:
Zdroj: Moscow University Chemistry Bulletin. 66:290-298
ISSN: 1935-0260
0027-1314
DOI: 10.3103/s0027131411050087
Popis: The properties of fine crystalline corundum doped with cerium (α-Al2O3: Ce3+) during synthesis in a supercritical fluid have been studied. The synthesis of corundum has been carried out by the thermal treatment of hydrargillite, Al(OH)3, at T = 415°C and {ie290-1} MPa in reaction media that contained from 0.001 to 0.25 wt % of cerium. Cerium ions are incorporated into the boehmite lattice during the transformation of hydrargillite into boehmite, which forms fine monocrystals of the doped corundum with a size from 20 to 50 μm. The size of the corundum crystals increases with increasing pressure and increasing concentration of cerium. The synthesized α-Al2O3: Ce3+ reveals a luminescent band in the UV region at 352 nm and a blue band at 421 nm. The intensity of the cerium ion luminescence in corundum increases with an increase in the water fluid pressure during synthesis. The follow-up annealing of α-Al2O3: Ce3+ at 1400°C in a vacuum leads to a decrease in the luminescence. It has been concluded that spectrally active complex structures that include cerium ions, oxygen vacancies, and hydroxyl groups are produced in the media of a supercritical water fluid upon the synthesis of boehmite and corundum. Exposure to high temperatures causes their transformation.
Databáze: OpenAIRE
Externí odkaz: