A study of tribo-electrification by means of a ballistic probe

Charge exchange processes have been studied occurring between small metal pellets and a teflon tube. A small lead pellet was propelled by compressed carbon dioxide at different speeds through a teflon tube. The charges incurred by the pellets and the tube were compared with the charges observed on copper spheres rolled through the tube, driven by gravity. In all the experiments, the charge on the pellets propelled by CO2 was measured using the ballistic method, and the charge incurred by the teflon tube was determined by a static Faraday cup. The experiments determined the effect of the frictional speed on the magnitude of the charges accumulated on the pellet and on the teflon tube. It was observed that the charge also depended on the work functions of the materials involved (lead, copper, teflon). The pellets' charges were found to range from +0.5 x 10(-8) to +3.0 x 10(-8) C, for the pellet speeds from 10 to 80 m . s(-1). A degree of systematic drift of the charge magnitude was encountered in the experiments, and a degree of charge imbalance incurred.