Relaxation phenomenon in composite materials

Laboratoires Arc Électrique et Plasmas Thermiques (CNRS UPESA 6069), 24 avenue des Landais, 63177 Aubière Cedex, France

Corresponding author: spectro@laept.univ-bpclermont.fr

Received: 27 October 1997
Revised: 28 April 1998
Accepted: 29 April 1998
Published online: 15 August 1998

Abstract

Dielectric measurement characteristics such as the dissipation factor, relative permittivity and conductivity as a function of temperature and frequency have been achieved on composite materials based on different epoxy resins filled with alumina inclusions. The analysis of the results show the presence of porosity and inhomogeneity in these materials. The study of the dissipation factor, as a function of temperature at high frequencies, has shown an unexpected absorption phenomenon in materials designed to be utilized as electrical insulators. The identification of the entities responsible for this relaxation shows that the entities result from one of the components of the material. These results can also confirm the inhomogeneity of the materials.