TRIBOLOGICAL PERFORMANCE ENHANCEMENT OF AMORPHOUS HARD CARBON-FILMS ON AISI-52100 BEARING STEEL

Hard carbon films synthesized on disks of hardened AISI 52100 steel by Ar+ beam sputtering were simultaneously bombarded by Ne+ at energy of 200 eV. Characteristics such as the surface morphology and structure, the film-substrate interface, and the hardness have been investigated. Transmission electron microscopy and Auger electron spectroscopy revealed that the films consisted of carbon atoms in an amorphous structure. Hard carbon films exhibited a smooth surface and a high microhardness of 1900 kgf mm(-2). Tribological experiments on the films were performed with a ball-on-disk tribometer without lubrication in a room-temperature atmosphere, except for the experiment at 107 degrees C. The curves of friction coefficient and the scanning electron microscopy pictures indicated that the hard carbon films had an excellent wear resistance. The wear coefficients and antiwear numbers confirmed that, as the wear load did not surpass 10 N, the wear of the films was mild, which showed a drastic reduction in the wear compared with AISI 52100 steel without hard carbon films.