A study of corona and breakdown voltages for glass beads or for polytetrafluorethylene (TFE) particulates fluidized by SF/sub 6/ is described. The effects of gap distance, pressure, field uniformity, fluidizing gas velocity and electrode orientation were evaluated. Finally, the data were compared with those for pure SF/sub 6/ without particulates under the same conditions. Glass beads (epsilon' = 7) often caused over 50% decrease from the corresponding SF/sub 6/-empty cell value. TFE (epsilon' = 2) in a non-uniform field can give an 80% gain over the SF/sub 6/-empty cell value. In a uniform field, the TFE was equivalent to or only about 20% less than the SF/sub 6/-empty cell value. By a correlation of Reynolds number versus Nusselt number for fluidized beds, an estimate was made of the heat transfer coefficient of glass beads and of TFE particulates. The TFE showed a value 60% of the glass bead heat transfer coefficient and both were comparable to or better than oil. The work of fluidizing the experimental system was computed. The pumping power estimated for fluidization and the consequent loss of transformer efficiency is so high that the fluidized bed heat transfer approach can only be considered for the large power transformer size. It was concluded that, due to decreased electrical properties, use of fluidized glass beads would be unsatisfactory in transformers. TFE particulatesshowed promise and are worthy of further evaluation.