Ion plated carbon films and their tribological properties
The conventional ion plating technique is described and the physicalmechanism and energies involved in the technique reviewed. The triode(assisted discharge) ion plating is studied and it is shown to increasethe ionization several times.Ion plating with a hollow cathode discharge is studied. The characteristicsof the deposited film under these conditions are presentedincluding thickness, adhesion and structure, and a comparison is madewith ion plating in abnormal glow discharge.Carbon films have been deposited by both chemical vapour depositionand ion plating using methane cracking and arc and electron beam gunevaporation sources. Triode ion plating has also been used. It isfound that the best way for depositing thick carbon films is theelectron beam gun method. The optimum plating conditions are determined.The characteristics of the ion plated carbon films are studied. Diffractionstudies indicate that the deposited carbon films are graphitic.Full structural details including graphiticity index, lattice parameters,grain size measurements are presented. Triode ion plating produces amore dense structure for carbon films.A pin-on-disc friction and wear rig has been designed and constructed.The friction and wear characteristics of ion plated carbon films havebeen studied in normal atmosphere and at higher temperature. It isconcluded that the friction of ion plated carbon films is slightlyhigher than that reported for graphites, however, the film exhibitsgood-wear resistance. A numerical investigation of the relationship between surface topographyand friction of ion plated carbon films is presented.
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