SYNTHESIS AND CHARACTERIZATION OF CARBON NITRIDE FILMS FOR TRIBOLOGICAL APPLICATIONS

IT HAS BEEN SUGGESTED THAT A HYPOTHETICAL CRYSTALLINE MATERIAL, BETA-C3N4, MAY BE HARDER THAN DIAMOND, PROVIDE EXCEPTIONAL WEAR AND CORROSION RESISTANCE, AND EXHIBIT AN EXTREMELY LOW COEFFICIENT OF FRICTION. NO ONE YET HAS SUCCESSFULLY SYNTHESIZED CONTINUOUS FILMS OF CRYSTALLINE CARBON NITRIDE. SUCH AN ACHIEVEMENT WOULD REPRESENT A TECHNICAL MILESTONE. THE AVAILABILITY OF SUPERHARD BETA-C3N4 IN THE FORM OF AN ADHERENT, SOLID LUBRICANT COATING WOULD PERMIT SIGNIFICANT ADVANCES TO BE MADE IN TRIBOLOGY. THE INNOVATION IN THIS PROJECT IS THE SYNTHESIS OF METASTABLE, CRYSTALLINE CARBON NITRIDE FILMS BY DUAL ION BEAM ASSISTED DEPOSITION (DIBAD). THE DIBAD PROCESS HAS BEEN USED SUCCESSFULLY TO SYNTHESIZE METASTABLE MATERIALS SUCH AS CUBIC BORON NITRIDE. IT ALSO OFFERS CONSIDERABLE PROMISE FOR SUCCESSFULLY GROWING FILMS OF BETA-C3N4. THE KEY TO SUCCESSFUL SYNTHESIS IS MOMENTUM TRANSFER INTO THE FILMS PER ARRIVING ATOM. DIBAD PROVIDES A WIDER WINDOW OF OPERATION THAN DOES A SINGLE ION BEAM EVAPORATION PROCESS. RESEARCHERS ARE DEMONSTRATING THE FEASIBILITY OF GROWING CONTINUOUS FILMS OF STOICHIOMETRIC AND NEAR-STOICHIOMETRIC BETA-C3N4 BY THE DIBAD PROCESS. DEPOSITION CONDITIONS ARE BEING DEFINED AND THE FILMS CHARACTERIZED IN TERMS OF THEIR COMPOSITION, MORPHOLOGY, DENSITY, STRUCTURE, THERMAL STABILITY, ADHESION, AND TRIBOLOGICAL PROPERTIES.