Synthesis and characterization of monophase CaO-TiO2-SiO2 (sphene) based glass-ceramics

Abstract

Sphene based glass-ceramics (CaTiSiO 5), an excellent candidate for a host lattice of ceramic materials and for nuclear waste immobilization, has been prepared from a powder mixture of CaCO 3 , TiO 2 and SiO 2 using vibro-milling for homogenization. Starting powders were melted at 1400 °C for 2 h, cooled to room temperature, grounded again, then crystallized by thermal treatment yielding a sphene glass-ceramic. The evolution of the phase composition during thermal treatment was investigated by X-ray powder diffraction (XRPD), FT-IR, Raman and thermal analyses (TG-DTA). Pure synthetic single phase sphene was formed at 800 °C for 4 h, even it is very hard to obtain monophase powder at such low temperature. Powder morphology was analyzed by scanning electron microscopy (SEM).

The analysis of the nucleation process of the lithium germanium phosphate glass

“…Efforts were made to minimize impurity levels in the glass by careful choice of starting materials due to possible effects of the impurities on the nucleation rates [13]. The glass was prepared by melting a homogeneous mixture of reagent-grade (99.99 %) Li 2 CO 3 , Al 2 O 3 , GeO 2, and (NH 4 ) 2 HPO 4 in a covered platinum crucible.…”

The thermophysical properties of primary phase in lithium germanium phosphate glass

“…Lithium germanium phosphate glasses have recently emerged as multipurpose materials and have been given great attention because of their potential applications in various solid-state devices [4]. The synthesis of the parent glass is an important step in preparing the final glass-ceramic material because the precursors and their percentage in the glass composition manage the precipitation of the crystalline phases [5]. By crystallization of some glasses from the system Li 2 O-Al 2 O 3 -GeO 2 -P 2 O 5 , the LiGe 2 (PO 4 ) 3 phase which belongs to the solid solutions with the general formula of Li 1+x M x Ge 2-x (PO 4 ) 3 (M=Al, V or Cr) is formed.…”