COMPARISON OF THE ELECTRICAL BREAKDOWN CHARACTERISTICS OF HYDROCARBON AND FLUOROCARBON LIQUIDS

Electric strength measurements are reported on a number of straight-chain and cyclic hydrocarbons, together with their fully fluorinated equivalents. The substitution of fluorine is seen to enhance the electric strength under uniform field conditions, although it produces and increase only for low molecular weight materials in divergent fields. A polarity effect is observed for non-uniform fields which is also influenced by the presence of fluorine in the molecular structure. Breakdown tests under conditions of ultrasonic irradiation have also been undertaken which would indicate the possible intervention of the gas phase in the breakdown mechanism even for uniform field conditions. The results are discussed in terms of the physical and chemical nature of the materials. © 1979.