Structure and crystallization behavior of 50CuO-xTiO2-(50-x)P2O5 (x=5-20) glasses

Glass samples with molar compositions of 50CuO-xTiO(2)-(50-x)P2O5 (x = 5, 10, 15, 20) were prepared. The crystalline phases, characteristic thermal temperature as well as crystallization kinetic parameters were investigated using X-ray diffraction (XRD) and differential thermal analysis (DTA) under non-isothermal conditions. The Fourier transformed infrared spectre scopy (FTIR) results show that the glass network depolymerizes with the increase of TiO2. However, TiO2 has an aggregation effect on the glass network. As a result of the depolymerization and aggregation effects, the glass transition temperature first increases and then decreases with TiO2. In the meantime, the glass is easier to crystallize. The XRD measurements indicate that when the content of TiO2 is more than 10 mol%, desired CuTi2(PO4)(3) phase appears in the heat-treated samples. The crystallization kinetics of the samples was studied using the Kissinger and Augis-Bennett models. It is evidenced that the crystallization activation energy increases with TiO2, while surface and bulk crystallization mechanisms dominate in the sample with 5 mol and 10-20 mol% TiO2, respectively.