Effect of rare-earth oxides on structure and chemical resistance of calcium aluminophosphate glasses

In this paper, the structure and chemical durability of calcium aluminophosphate glasses, containing rare earth oxides (La2O3 and CeO2), was investigated. The glasses were prepared and melted an electric furnace at temperatures ranging from 1350 to 1370 °C for 2-3 h; the produced glasses were examined by XRD, FTIR and SEM. Results from FTIR demonstrated that with more rare-earth oxides doped, the glass network depolymerized and the chains of phosphate in Q2 units depolymerized to the other kinds of phosphate groups, Q1 and Q0. XRD analysis confirmed that the surfaces of all the glass specimens after corrosion were amorphous. Densities of all glass specimens displayed an increased tendency with larger concentration of La2O3 or CeO2. As for the chemical durability, more and more cracks emerged on the glass surfaces after the alkali corrosion, and the La-doped glass specimens were more susceptible to corrosion than that of Ce-doped. The weight loss of different glasses in water and alkali solutions was measured. Comparing with the two groups, Ce-doped glass, which the weight loss rate was 9.36% when the amount of cerium oxide doped was 2.5 mol%, had a significant impact on water and alkali resistance than La-doped.