Dielectric Materials for Electrical Engineering

Chapter 5

Electrification 1

5.1. Introduction

It is now well known that setting a charged body in motion (in the case of solid particles in a flowing gas) creates currents and electric potentials which can sometimes reach significant values.

All the research already undertaken confirms the important role played by the nature and surface state of the materials involved in the transfer and accumulation of charges. In the next section, we shall attempt to analyze the processes which cause these phenomena.

5.2. Electrification of solid bodies by separation/contact

The generation of charges between two bodies which have been in contact is the fruit of the process known as electrification, i.e. the separation of charges with an opposite sign, combined by displacement or transport. Next, we shall examine the electrification process.

Three types of electrification exist, contact/separation electrification, electrification by influence, electrification by corona effect.

5.2.1. The process

The goal of this section is to recall the process of electrification of two solids during their contact, then their separation and to understand the mechanisms which come into play in order to take all the necessary precautions from a practical point of view to obtain reproducible results.

The contact electrification process always appears at an interface. It is due to the different nature of the two constituents. In all cases, a transfer of ions, due to their physico-chemical difference, or a transfer ...