Ti+N ion dual-implantation and co-implantation are used to improve the working surface of 9Crl8
bearing steel by plasma immersion ion implantation(PIII) processes. Untreated and PIII treated samples were evaluated
by the microhardness and vacuum fiction coefficient tests. Wear morphology of surfaces were also evaluated. It has
been found that the microhardness of treated samples increases substantially, and the maximum microhardness increases
68. 7%,the vacuum friction coefficient decreases from 0. 15 to 0. 08, the wear scar diameter and roughness are reduced
54. 4% and 37. 4% respectively. Comparison of the comprehensive properties of different PIII process, dualimplantation
process is better than co-implantation process under the same condition.