The 9Cr18 bearing steel surface was modified with metal
plasma immersion ion implantation(PIII).After titanium,mo lybdenum
and tungsten ions were implanted into the surface consecutively with a modified cathodic arc plasma source,nitrogen ions were im planted by PIII to grow a super hard,wear resist surfaces.The tribological properties of the modified 9Cr18 surfaces were then studied.Our re sults show that PIII may considerably improve the microhardness and wear properties of the steel surfaces.Moreover,the samples implanted with(Ti+N) and (Mo+N) have the best results.As compared with the samples treated only with nitrogen PIII,the metal ions implanted samples,after nitrogen PIII,have much higher
wear resistance.We may conclude that metal PIII is an effective technique to improve the tribological pro perties of 9Cr18 bearing steel.The X ray photoemission spectroscopy(XPS) results reveal that some nitride phases have been formed in the sur face layers.We suggest that these nitride phases play a key role in the improvement of surface properties of 9Cr18 steel.