Physical and structural properties of calcium iron phosphate glass doped with rare earth

The physical and structural properties of calcium iron phosphate glasses with different Gd2O3 contents and various rare earth oxides (Y2O3, La2O3, Nd2O3, Sm2O3, Gd2O3) were systematically studied by investigating their density, Vickers-hardness and Raman spectra. The results show that the compositions which contain up to 10 mol% of rare earth oxides formed homogeneous glasses and no crystalline phases. The properties of density and molar volume were discussed with different Gd2O3 contents and various rare earth elements, and Y-doped glass is an exception in molar volume. Vickers-hardness increases with the increase of cationic field strength of the corresponding rare earth elements. These physical properties have relations with the rare earth glass structure. The shape of the Raman spectra is affected and a very strong depolymerization appears in studied phosphate glasses with the Gd2O3 addition. The relative area of (PO3)2 − bonds in Q1 units with different rare earth glasses increase with increasing cationic field strength of corresponding rare earth ions. The P-O distance and rare earth coordination numbers were discussed to understand further the glass structure.