Impact of Al₂O₃, TiO₂ and ZnO addition on the crystallization of Yb³⁺ doped phosphate glass-ceramic

Abstract

<p>New Yb<sup>3+</sup>-doped phosphate glasses with a composition of (98.75-x) (90 NaPO<sub>3</sub> – 10 Na<sub>2</sub>O) – x (Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, or ZnO) – 1.25 Yb<sub>2</sub>O<sub>3</sub> (in mol-%), with x from 0 to 3, were prepared via conventional melting and quenching process. The thermal and physical properties were studied by differential thermal analysis (DTA) and density measurement, respectively. The glass structure was investigated using visible/infrared spectroscopy and the crystallization properties of the glasses using XRD. Changes in the glass composition were found to have an impact on the glass structure and more importantly on the crystallization process; the addition of Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub> and ZnO promotes the precipitation of the Na<sub>5</sub>P<sub>3</sub>O<sub>10</sub> crystalline phase at the expense of NaYb(P<sub>2</sub>O<sub>7</sub>) and NaPO<sub>3</sub> phases and more importantly, promotes surface crystallization at the expense of bulk crystallization.</p>