The structure of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides measured with X-ray diffraction method

The structure of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides was measured by XRD. The polycrystalline strontium–borate, SrB4O7 was synthesized via a solid state reaction route that involved heating stoichiometric mixtures of analytical grade SrCO3 and H3BO3 at 1073 K for 12 hours. Next, samples of a composition of x(2Bi2O3-V2O5)-(100-x)SrB4O7,where x=5 and 50 (in %mol) were prepared from reagent-grade Bi2O3, V2O5 and preprepared SrB4O7.While SBO glass samples (x = 0) were prepared from reagent-grade SrCO3 and H3BO3. Samples of glass were prepared by the conventional melt quenching technique. The melting was conducted in alumina crucibles at 1373 K for 2 hours. The melt was poured onto a preheated (573 K) brass plate and pressed by another plate to obtain flat circular disks of 1–2 mm thickness and 20–30 mm in diameter. The presence of crystalline phases and their phase composition were studied using an X-ray diffraction (XRD) method using a Philips X'Pert Pro MPD system with CuKα radiation. The XRD measurements were conducted at room temperature. Two types of samples were studied: as-quenched and heat-treated (SrB4O7, 5(2Bi2O3-V2O5)-95SrB4O7, 50(2Bi2O3-V2O5)-50SrB4O7). Sample names were simplified to SBO, as-quenched and heat-treated 5BiV-95SBO, as-quenched, partially crystallized, and fully crystallized 50BiV-50SBO. Heat-treated 5BiV-95SBO samples were obtained after a full cycle of high-temperature electrical measurements (3 days heating up to 813 K). Partially crystallized 50BiV-50SBO samples were obtained by heat treating in air at a temperature of 693 K for 3 hours and then kept the samples in the furnace to cool to room temperature. The crystallization temperature was determined on the basis of the DSC spectrum. During hightemperature electrical measurements of partially crystallized 50BiV-50SBO samples, further crystallization process took place. Samples after this process were described as fully crystallized. Detailed information can be found in: http://dx.doi.org/10.1016/j.ssi.2015.09.021