RESUMO
V2O5-P2O5-TeO2, a low-temperature vanadate-based glass sealant, was doped with metal oxides (MO = Ag2O, BaO, or CuO), which generate Ag, Ba, and Cu ions, respectively, to strengthen the glass structure and improve its water resistance. These ions reduce the number of nonbridging oxygen atoms in the glass structure by forming V-O-M or P-O-M crosslinks in the V2O5-P2O5 glass system. Structural analysis using Fourier-transform infrared spectroscopy indicated that the numbers of P-O-P, VâO, and V-O-V bonds decreased with increasing metal oxide content. Thermal property analyses revealed that the glass transition temperatures increased by approximately 2-30 °C and that the coefficients of thermal expansion only varied within approximately ±10×10-7 K-1 among all the glass samples. The contact angles were measured to quantify the wetting properties of the doped glasses. The contact angle increased from 11 to 36° with increasing metal oxide content at 410 °C. As an indication of the water resistances of the doped glasses, the dissolution rates of the 9 mol% Ag2O-doped and pure glasses were 0.078 and 0.523 g cm-2, respectively.
