Preparation and characterization of phosphate glass system A₂MnMP₂O₁₀ (A = Li, Na, K) and (M = W, Mo)

¹ Laboratoire de Physico-Chimie des Matériaux Inorganiques, Faculté des Sciences Aïn Chock, Casablanca, Morocco
² Univérsité Mohammed V Agdal, Laboratoire de Physico-Chimie des Matériaux, ENS Avenue Mohamed Bel Hassan El Ouazzani, BP. 5118, Takaddoum - Rabat, Maroc

Abstract

New materials based glassy phosphates and transition elements A₂MnMP₂O₁₀ (A = Li, Na, K) and (M = Mo, W) were prepared by direct fusion of the mixture of the reactants followed by quenching in the air. Analysis by X-ray diffraction showed that the obtained materials are amorphous. Differential scanning calorimetry DSC was used to determine the glass transition (Tg) and crystallization (Tc) temperatures. The thermal stability of tungsten glasses is higher than that of molybdenum ones. Tungsten plays, certainly, a role of cross-linking polyphosphate groups by creating more covalent new bonds P-O-W and W-O-W. Moreover, it has been shown that lithium glasses are more stable than sodium and potassium, probably due to the potassium hygroscopy. Raman analysis confirms that the studied glasses have similar structures and the predominant structural units are PO₄, P₂O₇ and MO₆ polyhedra (M = W, Mo, Mn).