Effect of molybdenum oxide addition on the durability and structure of iron phosphate glasses

Abstract

Molybdenum oxide (MoO3)-containing iron phosphate (FeP) glasses with an analyzed Fe/P molar ratio of 0.410.43 and 043 mol % MoO3 were prepared via a conventional melt-quenching method. The X-ray diffraction analysis revealed that all prepared samples had an X-ray non-crystalline state with a halo pattern. The dependency of the MoO3 concentration on the glass transition temperature and water durability were evaluated. The water durability was examined in terms of glass plates with dimensions of 10 © 10 © 3 mm3 via a static leaching test at 120 °C for 72 h using ultrapure water. Raman spectroscopy was used for the analysis of the PO4 Qn structures (n = 0, 1, 2) and the Mo5+/Mo6+ species. The FeP glasses containing 817 mol % MoO3 consisted mainly of PO4 Q1 structural units as well as both Mo5+O6 distorted octahedra and Mo6+O6 octahedra and a Fe-related polyhedra with a minimization of POP and MoOMo bonds. These structural features were qualitatively related to the improved properties of both thermal stability against crystallization and water durability for the MoO3-containing FeP glasses.