Effect of Co Ion Implantation on Friction and Wear Behavior of Stainless Steel

1Cr18Ni9Ti stainless steel was ion implanted with Co using metal vapor vacuum arc ion source (Mevva), at an accelerating voltage of 40 kV, implantation doses of 3×1017/cm2 and 5×1017/cm2, and ion current densities of 13 μA/cm2, 22 μA/cm2 and 32 μA/cm2. The friction and wear behavior of the Coion implanted stainless steel sliding against SAE52100 steel was investigated on a 2002I vacuum friction and wear tester, in a ballondisc contact configuration. The worn surface morphologies of the unimplanted and various implanted stainless steel specimens were observed with a scanning electron microscope. The results showed that the Coimplanted stainless steel specimens had much higher hardness and better wearresistance than the unimplanted one, while the hardness and wearresistance of the implanted specimens were dependent on the ionimplantation parameters. The friction coefficient decreased from 0.74 to 0.20 after Co implantation and the wear volume reduced by 25%~45% as compared to the unimplanted specimen. Coion implantation of the stainless steel also led to differences in the worn surface morphologies of the stainless steel specimens, which accounted for their different friction and wear behaviors to some extent. The stainless steel specimen implanted at a current density of 22 μA/cm2 and a dose of 5×1017/cm2 shoed the best frictionreducing and antiwear ability.