Abstract
Contact charging is one of the fundamental phenomena in powder handling, and various applications based on this phenomenon have been developed. However, there are still many unsolved problems in the charging and the reported experimental results are inconsistent with one another. In the present review, the basic concepts of contact charging are summarized particularly focusing on the contact potential difference based on the work functions. Furthermore, the particle charging caused by repeated impacts is described theoretically. In addition, useful methods for measuring particle charge distribution and evaluating important electrostatic properties are introduced with the examples.
