Objectif The aim is to improve surfaces of electrical contacts, in order to achieve better reliability against corrosion, aging, wear and vibration, and to decrease production cost through noble metal saving or improvements of plating. This will be done by better control of undesired film formation, selection of surface additives (such as lubricants thin film deposition procedures set up). The research investigated methods for improving the surfaces of electrical contacts, in order to achieve better reliability against corrosion, ageing, wear and vibration, and to decrease production cost through noble metal saving or improvements of plating. The control of undesired film formation, the selection of surface additives (such as lubricants) and thin film deposition procedures were studied in particular.Research has been carried out in order to improve electrical contact surfaces involved in data processing, telecommunication, automotive and consumer applications. Research focused on replacing gold by an organic film, either liquid or solid film and screening different types of existing metallic plating together with new or existing lubricants in order to optimize the coupling between both. With respect to the organic film, 2 ways were investigated to protect the nickel used to cover the substrate. The first was to realize a thin film of liquid perfluorinated polyether (PFPE) on the metal. The second way was to electropolymerize polyacrylonitrile (PAN) on the metal, the polymer layer being heat treated in a second phase to ensure conductivity. The PAN coating was chosen to realize a connector. However results on connector has been disappointing: contact resistance reached acceptable value only after a few sliding cycles and the friction coefficient was often too high. A wide range of contact metallurgies used in automotive applications was surveyed and a representative test matrix selected. These included various tin, gold and silver alloys as well as less traditional finishes such as nickel and clad inlay materials. The types of protective greases available were also surveyed and an initial screening process conducted. The test procedures were derived from a survey of accelerated environmental tests for automotive electronics and connectors and in addition to these tests a large number samples of the test plates were exposed to various real automotive environments for up to 2 years. The results of the test gave the following conclusions. Care should be taken to avoid contact degradation due to copper diffusion through tin and silver at elevated temperatures. Gold and silver surfaces are unlikely to suffer from fretting corrosion in automotive environments. Also, contacts with thin layer of gold are less corrosion resistant than tinned finishes in under bonnet environments. Finally, it was shown that lubricants do improve contact reliability but only if the product is properly formulated and specific to the applicationInfluence of film thickness, in the range of 1 to 100 mm, will be studied for various layers such as lubricants, oxidation or conversion products, grafted polymers. An original procedure based upon electropolymerisation, presently at the research stage, will be developed. Degradation mechanisms in an aggressive automotive environment will be studied on a quantitative basis; test methods will be developed; effect of applied voltage and current will be taken into account. Champ scientifique engineering and technologymechanical engineeringtribologylubricationnatural scienceschemical sciencesinorganic chemistrytransition metalsnatural scienceschemical sciencesinorganic chemistrypost-transition metalsengineering and technologymaterials engineeringcoating and filmsengineering and technologymaterials engineeringmetallurgy Programme(s) FP2-BRITE/EURAM 1 - Specific research and technological development programme (EEC) in the fields of industrial manufacturing technologies and advanced materials applications (BRITE/EURAM), 1989-1992 Thème(s) Data not available Appel à propositions Data not available Régime de financement Data not available Coordinateur Souriau et Cie SA Contribution de l’UE Aucune donnée Adresse 145 rue Yves le Coz 78035 Versailles France Voir sur la carte Coût total Aucune donnée Participants (5) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire Centre for Renewable Energy Systems Technology Royaume-Uni Contribution de l’UE Aucune donnée Adresse Leicestershire LE11 3TU Loughborough Voir sur la carte Liens Site web Opens in new window Coût total Aucune donnée Commissariat à l'Energie Atomique (CEA) France Contribution de l’UE Aucune donnée Adresse Voir sur la carte Coût total Aucune donnée Laboratoire de Genie Electrique de Paris France Contribution de l’UE Aucune donnée Adresse Voir sur la carte Coût total Aucune donnée Lucas Automotive Ltd Royaume-Uni Contribution de l’UE Aucune donnée Adresse Brueton House New Road B91 3TX Solihull Voir sur la carte Coût total Aucune donnée Morgan Rocol Royaume-Uni Contribution de l’UE Aucune donnée Adresse Rocol House Swillington LS26 8BS Leeds Voir sur la carte Coût total Aucune donnée
