Eur. Phys. J. AP 4, 107-116 (1998)
https://doi.org/10.1051/epjap:1998249

Surface-potential decay due to surface conduction

¹ Schneider Electric SA, Direction de Recherche de Matériaux, rue H. Tarze, 38050 Grenoble Cedex 9, France
² Laboratoire d'Électrostatique et de Matériaux Diélectriques (UMR 5517), Université J. Fourier, CNRS, BP 166, 38042 Grenoble Cedex 9, France

Corresponding author: gosse@labs.polycnrs-gre.fr

Received: 10 October 1997
Revised: 6 April 1998
Accepted: 4 June 1998
Published online: 15 October 1998

Abstract

The time dependence of the surface potential of an insulating material is theoretically investigated in the case of simultaneous surface and volume ohmic conduction. When the material presents a constant surface conductivity, the first part of the decrease with time of the surface potential is strongly influenced by the initial distribution of charges and cannot be used to determine the surface conductivity. On the other hand, at rather long times after the surface has been charged, the potential of the surface follows an exponential variation with time, the expression of the corresponding time constant is given in different cases. This model is found in good agreement with experiments performed with photo-oxidized epoxy resins placed in a humid atmosphere.