CORROSION AND MECHANICAL-BEHAVIOR OF ION-IMPLANTED BEARING STEELS FORIMPROVED FRETTING BEHAVIOR

Ion implantation of AISI 52100 and 1070 steels was conducted in order to improve the corrosion, wear and ultimately the fretting behavior of the steels. Implantations consisted of 1 X 10(17) Ta+ cm-2, 3 x 10(17 ) Ti+ cm-2+1.5 x 10(17) C+ cm-2, and 3.1 x 10(17) Ti+ cm-2 + 1.55 x 10 (17) N2+ cm-2. All implantations were successful in improving the corr osion resistance. On average, the peak anodic current was reduced by o ver 300 mV, the passivation potential was reduced, and the pitting pot ential was increased by over 1000 mV in 0.01 M NaCl. Ti + C and Ti + N implantations increased the load-carrying capacity in lubricated scuf fing tests by 60% and 40% respectively. Ta produced no improvement in scuffing resistance. Ti + N implantation increased the hardness by 25% over the unimplanted steel and both Ti + C and Ta implantation reduce d the surface hardness. Fretting wear was reduced only slightly in the Ta implanted sample and increased in both the Ti + C and Ti + N impla nted samples with the latter showing 4-5 times the weight loss as the unimplanted sample. The correlation between fretting and hardness supp orts a mechanism in which the hard surface layer breaks into fine part icles which act as an abrasive under the intense load of the balls.