Electric field induced softening of glass: What can it tell about the mechanism of flash sintering?
March 10-15, 2019
Electric field induced softening (EFIS) of glass is a recently discovered phenomenon, which was inspired by dramatic effects of electric field on sintering of ceramic powders. It represents the effect of DC or AC electric field on the softening of glass that is heated at a constant rate under fixed compressive load. As shown in Fig. 1(a), the application of applied voltage reduces the softening temperature, and the softening transition becomes significantly sharper when voltage is above a critical value. Remarkably, this behavior is similar to that reported for flash sintering, as seen in Fig. 1(b). In both types of experiments, emission of white light is observed when the sample is in the vicinity of sharp transition. The power density at the onset of EFIS and flash sintering is comparable at ~1W/cm2. Neither phenomena can be explained as Joule heating of a homogeneous solid. Notwithstanding these empirical similarities, we note that flash sintering of powders of varying properties is a far more complex phenomenon than heating of a clear, homogeneous, ion conducting silicate glass. As a result, EFIS is relatively well understood, while there are several diverging explanations of flash sintering that has been investigated much more extensively.
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Himanshu Jain, "Electric field induced softening of glass: What can it tell about the mechanism of flash sintering?" in "Electric Field Enhanced Processing of Advanced Materials II: Complexities and Opportunities", Rishi Raj, University of Colorado, USA Olivier Guillon, Forschungzentrum Jülich, Germany Hidehiro Yoshida, National Institute for Materials Science, Japan Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/efe_advancedmaterials_ii/67