Electrical conductivity measurements of oxides from molten state to glassy state

This article describes an experimental setup designed to measure the electrical conductivity of molten and viscous oxides from 1200 to 400 degreesC. The 4-electrode method was adapted to perform impedance measurements over wide temperature and frequency ranges. High-frequency electrode effects were calculated and eliminated. Low-frequency electrode polarization was avoided with the 4-electrode configuration. The ac impedance was measured at one immersion depth. Calibration and complex impedance analysis were necessary to obtain the electrical conductivity of the melt. The results of this technique for a borosilicate melt are presented and compared with those of high-temperature calibration-free solid-state measurements, and their accuracy is evaluated. (C) 2003 American Institute of Physics.