Fracture behavior of graphite coated with titanium compounds by chemical vapor deposition

TiC, TiN, TiB2, and TiCN coatings were deposited on graphite by high-temperature chemical vapor deposition. Pin-pull tests were used to investigate the adhesion of the coatings to the graphite. Interfacial adhesion was excellent and failure occurred in the graphite itself. The distribution of failure stresses was analyzed by Weibull statistical analysis, which showed a good fit to the Weibull expression; failure stresses for the coated graphite were approximately one-half that of the uncoated graphite, although the Weibull moduli were comparable.