Properties of SiO2-Bi2O3-Na2O Glass
1970 Volume 78 Issue 897 Pages 165-171
Details
1970 Volume 78 Issue 897 Pages 165-171
Ternary glasses of the system SiO2-Bi2O3-Na2O were prepared by fusion in porcelain crucibles. The range of glass formation in the system was also studied.
Thermal, optical, electrical properties for the glass prepared were investigated, and the results were obtained as follows:
Thermal expansion coefficient and alkali soluble quantity of these glasses were increased with the increase of Na2O contents, and also specific gravity and refractive index were increased with increasing Bi2O3 contents.
Electrical resistivity of these glasses were 101-105(Ωcm) at 350°C, and dielectric constant and dissipation factor were ε=12.7-15.8, tan δ=0.001-0.007 respectively at room temperature.
By infrared absorption spectra, absorption bands that can be ascribed to OH-, CO32- ion and Si-O vibration were observed.
Results of X-ray diffraction, a halo that appeared at an angle of about 30°(2 θ) was shifted toward a low diffraction angle as decreasing Na2O contents.
A. E. Owen reported as follows:
In glass systems where the electric current is thought to be carried by alkali ions there is an approximately linear relationship between resistivity and activation energy over a very wide range of alkali concentration. In this work, however, several samples appeared out of accordance with the linear relationship.
Bi2O3 behaves as both of network-former and network-modifier oxide in the glass, and besides, Bi element is classed with semiconductor-metals in periodic table. By these results, it was regarded that the mechanism of electric conduction in these glasses was not only ionic conduction but also more complex mechanism including electronic conduction.
