Theoretical and phenomenological analogies between flash sintering and dielectric breakdown in α-alumina

alpha-alumina pre-sintered samples were subjected to flash sintering at 1200 degrees C under differing electric field strengths. The analysis of the relation between the incubation time and pre-sintering temperature clearly shows that the presence of pores and surfaces within the sample plays a central role in field-assisted sintering behavior of the material. The observed behavior is accounted for by the strong non-linear electrical conductivity shown by porous alumina at high field strength. The observed non-ohmic conductivity can also be related to the pre-breakdown behavior previously described by Frenkel. Literature results suggest that the field involved in flash sintering of alumina is comparable with the dielectric strength at high temperature. We can also state that dielectric breakdown and flash sintering in alumina are associated with similar physical phenomena. Published by AIP Publishing.