STRONG WEAR REDUCTION OF HIGH-DOSE CARBON-IMPLANTED AISI-52100 STEEL

AISI 52100 steel was implanted at 100 keV with doses in the range 4 X 10(17)-3 X 10(18) C+/cm2. Tribological tests were carried out on an oscillating ball-on-disk tester. The friction coefficient of the steel implanted with a dose of 3 X 10(18)/cm2 was reduced by a factor of 3 for far more than 6 h. The wear behaviour of the steel shows normal wear up to a depth of 0.15-mu-m, being the range of the implanted carbon ions. Thereafter, a very low wear rate is obtained for more than 6 h (1.5 X 10(5) cycles). The ball shows also no wear during this period. The steel was also studied by Mossbauer spectroscopy for various doses. At the lowest dose, epsilon-carbide is formed. For the higher doses the amount of epsilon-carbide increases, and the composition approaches that of epsilon-Fe2.2C. The epsilon-carbide was also found by glancing-angle X-ray diffraction. Fe and C profiles were obtained from the Rutherford backscattering spectra. It was found that besides the epsilon-carbide a large amount of pure carbon is present in the implanted layer.