PREPARATION, PROPERTIES AND STRUCTURE OF METAL CONTAINING AMORPHOUS HYDROGENATED CARBON FILMS

Abstract

Amorphous hydrogenated carbon (a-C:H) films and hydrocarbon films containing transition metals (Me-C:H) were prepared by glow discharge and reactive sputtering techniques at relatively low substrate temperatures (100 - 200°C). The tribological properties of both these types of coating materials will be compared. For steel counterparts Me-C:H films show very low friction coefficients (0·15 > μ > 0·05), depending on the used metal as well as on the metal content. The a-C:H films are more wear resistant but their friction coefficients are slightly higher. Measurements of microhardness and elastic modulus by a nanometer-indentation technique could not reveal a comprehensive understanding of the excellent tribological properties of the Me-C:H films.The experimental results of analytical investigations by photoelectron spectroscopy and X-ray diffraction can be explained by a structure model consisting of a homogeneous mixture of amorphous carbon (a-C:H) and metal carbides. A shell of modified a-C:H material around the carbide crystallites seem to affect the physical properties of the films