Wetting and surface tension of bismate glass melt

Lead oxide glass frits are used widely in the electronics industry for low-temperature firing. On the other hand, one of the low-sintering and low-melting lead-free glass systems available, the bismate glass system, is considered to be an alternative to lead oxide glass. In order to extend the applications of Bi2O3 glasses, this study examined the thermophysical properties of low-melting Bi2O3–B2O3–ZnO–BaO–Al2O3–SiO2 glass frits with various ZnO/B2O3 ratios. The fundamental thermal properties, such as glass transition temperature and softening point, were examined by differential thermal analysis and a glass softening point determination system. The wetting angles, viscosities and surface tension of the various bismate glasses on an alumina substrate were measured using hot-stage microscopy and the sessile drop method. These thermophysical properties will be helpful in understanding the work of adhesion and the liquid spread kinetics of glass frits.