Ceramics-Silikáty 47 (2) 63-79 (2003)

CRYSTALLIZATION CHARACTERISTICS OF ALKALI-IRON GERMANATE CONTAINING SILICATE GLASSES

S.M. SALMAN, S.N. SALAMA, H. DARWISH

The crystallization characteristics of the glasses based on stoichiometric composition of diopside (CaMgSi₂O₆)-lithium iron germanate (LiFeGe₂O₆) have been investigated. The effect of the compositional variation of the two pyroxene members CaMgSi₂O₆-LiFeGe₂O₆ on the thermal history of the glasses and type of the solid solution phases formed as well as the resulting microstructure formed by crystallization are traced by differential thermal analysis, X-ray diffraction analysis and scanning electron microscopy. In most cases intense uniform volume crystallization of fine-grained microstructure are achieved by increasing the LiFeGe₂O₆ content at the expense of CaMgSi₂O₆ in the glasses. Varieties of pyroxene ss of the two components are mostly detected by XRD from the high CaO, MgO-containing glasses, however, both LiFeGe₂O₆ and diopside are crystallized in the high iron-GeO₂-containing variety. The object of the present work was to understand the role of the glass oxide constituents in determining the type of the solid solution phases formed and the microstructure of the resulting material.

Keywords: Glass-ceramics, Diopside, Lithium iron germanate, Pyroxene members.