Abstract: In order to improve the tribological properties of 9Cr18Mo stainless bearing steel,the titanium was sputtering deposited onto quenched 9Cr18Mo specimens by argon ions and the deposited layers were simultaneously bombarded by argon,nitrogen or carbon ions respectively.The elemental depth profiles in the deposited layers were measured by Auger electron spectroscopy;The new phases formed in the deposited layers were analyzed by using glancing angle X ray diffraction;The tribological properties of the surfaces including the microhardness,the friction factor and the wear were characterized.It showed that,due to the ion beam enhanced depositions,the surface microhardness of the specimens was increased .The friction factor and the wear of the specimens against the hardened GCr15 steel balls were also improved.Combining the structural and the elemental characterization results, the hard phases formed in the deposited layers,like Fe 2Ti or CrN,are responsible for the observed tribological improvements.The co existence of oxygen and titanium in the deposited layers and the carbon contamination on the surfaces also have certain minor contributions to this improvements.The above results suggest that the ion beam enhanced deposition is an effective way in improving the tribological properties of the 9Cr18Mo stainless bearing steel.