A study of the electret properties of Carnauba Wax

Carnauba wax electrets were made by electrification with high fields below the melting point of the wax. Measurements were made of the discharge current of an electret and the torque on an electret in an electric field. A torsion balance was constructed to measure the torque. Experiments were conducted both with natural wax and with wax that had been treated to remove impurities.It was found that for an electret of natural wax the discharge current fell off with time after removal of the forming field; the magnitude of the current being approximately inversely proportional to the time since the field was removed.The torque on such an electret rises from zero with time, the magnitude being given by T = c(1 - i/t) where c is a constant and t is the time since the forming field was removed. Removal of occluded water changes the functions for the decay of discharge current and rise in torque to exponentials. Thorough filtering and an attempt at removal of ionic impurities increased the final value of the torque.The results are in agreement with the theory proposed by B. Gross.