Surface conductivity at the interface between ceramics and transformer oil

Abstract

It is expected that in liquid dielectrics a special layer with increasing conductivity can be formed close to the boundary with the solid. This behaviour has both chemical and physical origins. According to our computations one of the reasons could be enhanced dissociation of dissolved electrolytes near the solids with higher permittivity. We have performed experiments with transformer oil and ceramics. Instead of using the usual method for surface conductivity (SC) measurements, a new method based on foil electrodes of different thicknesses between two plane ceramic samples is developed. Experimental data show that the SC σs is proportional to the bulk conductivity raised to the power two-thirds . This corresponds neither to our theoretical treatment nor to the usual treatment taking into consideration the ζ-potential of the double electric layer.

Analysis of Loss Factor of Supercooled Pore Water at Frequencies of 60–140 GHz

“…The second addend in (3) may be related to the result of interaction between the molecules of water with the material of the pore surface. In [21,22] emergence of a conductive layer h ∼ 0.1 . .…”

“…As clusters emerge in the medium, its properties may be also affected by formation of ferroelectric ice 0 at the temperatures below −23 • C. The existence of this ice was discovered at computer simulation [18,19], and its influence on the microwave properties of porous media was experimentally established in [20]. During interaction with the matrix material, ice 0 forms a thin conductive layer at the boundary of the media due to the sharp difference in the values of static dielectric permittivity (ε s ) [21,22]. Hence, at occurrence of the phase transition of water into ice 0 at temperatures below −50 • C, for porous medium with the pore diameter 5 .…”

Ice 0: the experimental proof of its existence – the result of combining approaches used in radiophysics, geology and geography

“…Success of the new solution was that we took notice of a study of the Novosibirsk scientists who investigated the issues of electric breakdown in high-voltage transformers. It turned out that at the interface of ferroelectrics and dielectrics, a layer of high electric conductivity emerges [4]. This property allowed us to make an experiment on identifying formation of ice 0 in a porous dielectric medium [2], as it followed from the results [3] that this ice is a ferroelectric.…”

Dielectric Modulation of Ion Transport near Interfaces

“…The modulation of ion-ion interactions by polarizable surfaces [33] and the consequent changes in ionic atmosphere [18,34] near interfaces have been predicted before. Experimental support for the weakening of ion-ion interactions near a high-permittivity material is provided by the observation of enhanced dissociation of a weak electrolyte, leading to more free charge carriers and an increase in conductivity [35]. However, to the best of our knowledge, the modulation of ion mobilities by polarizable interfaces through changes in the ionic atmosphere has not been reported before.…”