Structural states of Co(II) in β-eucryptite-based glass-ceramics nucleated with ZrO2

Autor: Kang, Uk, Dymshits, O.S., Zhilin, A.A., Chuvaeva, T.I., Petrovsky, G.T.
Zdroj: Journal of Non-Crystalline Solids; September 1996, Vol. 204 Issue: 2 p151-157, 7p
Abstrakt: The structure of a Co(II) ion lithium aluminosilicate glass and glass-ceramics nucleated with ZrO2was studied by optical spectra and X-ray diffraction analysis. Three types of Co(II) absorption spectra were revealed. A type I spectrum arises from the absorption of six-coordinated and four-coordinated Co(II) in an initial glass. A type II spectrum appears when, in the course of crystallization of β-eucryptite solid solution, Co(II) ions enter into microcrystals of this phase, mainly, in sixfold positions, isomorphously substituting for Li(I) ions. At crystallization temperature higher than 950°C, the ordering of microcrystals of β-eucryptite solid solution takes place, which leads to Co(II) coordination change to fourfold positions, which leads to a type III spectrum. The Co(II) structural change in β-eucryptite solid solution was confirmed by the temperature dependence of lattice parameters of the unit cell.
Databáze: Supplemental Index