Dielectric breakdown test of monolithic ceramic: Effects of electrode and sample thickness.

To comprehend the mechanism of dielectric breakdown (DB) is fundamental for the work on improving the dielectric breakdown strength (DBS). Changing DB test in order to find the difference in DBS and DB channels is always one of the most important methods of studying mechanism of DB. In this paper, 6 different electrode set-ups were applied to the DB test of alumina ceramics with various sample thicknesses, and the effects of electrode and sample thickness were analyzed from the statistical characteristics of DBS data. Some phenomena were found: DBS first increased and then decreased with the increase of electrode size, and this could be attributed to the effect of electric field concentration and the area effect, and Weibull scaling law could be applied to analyze the area effect; the thickness-dependence of DBS was found in every electrode set-up, and none of the proposed mechanisms of DB could fully explain it; multi-layer series improved the high voltage resistance of alumina ceramic sheets, and the improvement factor was smaller than the predicted value on the base that the voltage-distribution ratio is equal in each layer. [ABSTRACT FROM AUTHOR]