Revista de ciencias e ingeniería de materiales

State of the Art and Recent Advances in Electrical Conductive Coatings by Sol-Gel Process

Abstract

Clement Genet, Hiba Azougaghe, Marie Gressier, Florence Ansart, Olivier Gavard, Marie-Joelle Menu*

With the development of smart materials and the requirement of multifunctional systems, coatings were developed with the aim to improve and optimize many properties and especially in the electrical field (resistivity, conductivity, permittivity,..) Relative to the electrical conductivity, the need is growing in many activity areas with the recent tendencies (green technology and energy). Recently, the sol-gel route to process coatings was investigated for its ability to develop innovative multifunctional coatings. Because the sol-gel matrix is known to be completely insulating, the conductivity can be brought by the development of a composite material, with the incorporation of conductive fillers into the insulating network. The aim of this paper is to present an overview of the sol-gel coatings, dedicated to the electrical conduction, started in the 2000’s. A rapid introduction will set the context including many “standard” applications of sol-gel coatings. Then, studies are gathered according to the fillers incorporated in the sol-gel formulation (Tables 1-3). Each coating is described in detailed. Correlations and tendencies are identified and discussed. The lowest surface electrical resistance is obtained using metallic fillers (145 mΩâ?¡), but the carbon fillers are very promising taking benefit of their various form factors. After an exhaustive presentation of the state of the art in this field, some new quantitative examples of coatings recently developed are presented. Various systems and architectures are detailed with associated applications. The major results show a surface electrical resistance comparable to the best values listed in the literature (around 130 mΩâ?¡), but with carbon fillers against metallic fillers. Furthermore, the combination of carbon fillers and the capability to develop a sol-gel multi-layer is demonstrated. Finally, a key point is relative to the application of these conductive sol-gel coatings on a complex shape substrate.