Obiettivo Some coatings, such as conventional WC-Co systems, are capable of providing unexpected friction properties. The research deals with the study of this new family of coatings with improved friction properties. The objectives are: - Modelling their behaviour in order then to generalize their use with the maximum potential of success. - Studying the interaction between the friction properties and the operating conditions with a view to tracing all maximum permissible performance. - Checking the correct balance between the coating properties and their use on certain diesel engine components. Much of this work was devoted to basic research into the influence of different parameters on the tribological properties of tungsten carbide cobalt coatings and analysis of the friction mechanisms. This was done by taking into account the main parameters - such as plasma power, type and percentage of secondary gases, plasma gas flow, spraying distance, composition and manufacturing process of powders (sintered/agglomerated/coated), and studying tribological behaviour in various situations (mating materials, geometry of contact, lubrication, etc).The friction properties of the tungsten carbide cobalt coatings are closely dependent on the mode and degree of decomposition of the carbides on spraying. The coatings with improved friction properties show increased adhesive wear resistance.Feasibility trials were conducted using a diesel engine equipped with special components to which the new ceramic coatings had been applied. Improvements in oil consumption were demonstrated.IT IS PROPOSED TO INVESTIGATE A NEW COMPLEMENTARY APPROACH TO AN EARLY INVENTION OF HYDROMECANIQUE ET FROTTEMENT WHERE PLASMA SPRAYED CERAMIC COATINGS OF THE "CARBIDE & BINDING ELEMENT" TYPE , HAVE THE PROPERTY OF BEING AUTOLUBRICATING I.E. THEY GIVE A VERY SMALL VALUE OF THE FRICTION COEFFICIENT COMPARED TO THE ONE OBTAINED WITH THE BEST KNOWN CERAMIC MATERIALS. IT HAS BEEN SHOWN THAT, FOR A LUBRICATING LAYER TO APPEAR IT IS NECESSARY TO HAVE FREE CARBON IN THE CERAMIC COATING WHILE, AT THE SAME TIME PHYSICO-CHEMICAL TRANSFORMATIONS OF THE BINDING ELEMENT, DUE TO THE FRICTION, MAY BE INVOLVED. TO SUPPORT THE RESEARCH DETAILED METALLURGICAL INVESTIGATIONS, EXPERIMENTAL VIBROMETRY PROGRAMS AND FRICTION TESTS ON REAL ENGINES WILL BE CARRIED OUT. THE PRELIMINARY STUDIES HAVE LEAD TO AN INITIAL UNDERSTANDING OF THE FRICTION MECHANISM. AS SOON AS FRICTION COMMENCES, A LUBRICATING LAYER (TRANSFER LAYER) IS GENERATED. IN CASES OF REMOVAL DUE TO WEAR, IT CAN BE GENERATED AGAIN DURING THE FRICTION. IT IS QUITE REALISTIC TO THINK THAT, IF SUCCESSFUL, THIS RESEARCH WILL HAVE AN IMPORTANT INDUSTRIAL IMPACT IN AREAS LIKE CYLINDER LINERS, PISTONS, PISTON RINGS, VALVE ROCKERS, ETC. Campo scientifico engineering and technologymechanical engineeringtribologylubricationnatural scienceschemical sciencesinorganic chemistryinorganic compoundsnatural scienceschemical sciencesinorganic chemistrytransition metalsengineering and technologymaterials engineeringcoating and filmsengineering and technologymaterials engineeringceramics Programma(i) FP1-EURAM - Research programme (EEC) on materials (raw materials and advanced materials) - Advanced materials (EURAM) -, 1986-1989 Argomento(i) Data not available Invito a presentare proposte Data not available Meccanismo di finanziamento CSC - Cost-sharing contracts Coordinatore Hydromécanique et Frottement SA Contributo UE Nessun dato Indirizzo Rue Benoit Fourneyron Zone Industrielle Sud 42166 Andrézieux-Bouthéon Francia Mostra sulla mappa Costo totale Nessun dato Partecipanti (2) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto CORK REGIONAL TECHNICAL COLLEGE Irlanda Contributo UE Nessun dato Indirizzo Mostra sulla mappa Costo totale Nessun dato EMPRESA NACIONAL DE AUTOCAMIONES SA Spagna Contributo UE Nessun dato Indirizzo Mostra sulla mappa Costo totale Nessun dato
