Thermic stability and microstructure of rare earth doped boronaluminasilicate glass

The thermic stability of rare earth doped BaO-Al₂O₃-B₂O₃- SiO₂ glasses is tested, and the phases separation and devitrification course of the M series glass heat-treated at different conditions are investigated by XRD and TEM/EDS. It is shown that with the rare earth content increasing gradually, the glass thermic stability increases firstly and lowers finally. The opacity of glass is due to the phases separation initially, and the rare earth ions concentrate into the boronalumina phase can result in the formation of devitrification of M glass at higher temperature for a long time. In addition, the XRD spectrum shows that the crystal maybe SmAl_2.07(B₄O₁₀)O_0.6, and the MAS NMR spectra show that aluminous polyhedrons have much stability than boric polyhedrons during the course of heat-treatment.