Dielectric measurements for the examination of electrostatic charging of powders

Abstract

The electrostatic charge accumulation of extremely pure substances usually makes the manufacturing technology more difficult. The electrostatic behaviour of the materials can be examined by the measurement of charge decay time, but the conductivity of pure materials is very low, therefore they show very long charge decaying times. Hence, this quantity is not applicable for reliable electrostatic characterisation of pure powders. In this investigation, dielectric and charge accumulation measurements were executed on extremely pure powders. The results of leakage current and voltage response methods show significant difference between the powders according to their electrostatic behaviour. The result of dielectric measurements is confirmed by the charge accumulation measurement. The findings reveal the importance of the investigation of slow polarisation mechanisms in the charge accumulation processes of powders.