Nanocomposite thin films for surface protection in electrical contact applications

Increased demands on reliability, operations in harsh environments and miniaturisation of electrical contacts, justify research on totally innovating coatings. Such films require many specific properties such as proper conduction and mechanical behaviour. The approach reported here is based on the idea of associating a polymer matrix and a conducting charge. The polymer matrix was chosen to resist mechanical degradation while the charge allows good conductivity. The first results obtained by associating a carbon nanotube (CNT) network to a fluorinated polymer thin layer are presented here. Several characterisation techniques such as XPS, FT-IR and Raman spectroscopy have allowed the control of the various steps of the elaboration process. Films were deposited on cuprous coupons with a nickel underlayer and an electrodeposited gold final layer. Several matrixes were studied. The properties of these thin films were investigated in a ball plane contact configuration: first electrical and mechanical characterisations show low values of contact resistance and friction coefficient. The CNT network influence is investigated both at a macroscopic scale and at a microscopic one.