Ion Implantation into High-Speed Steel for Improved Tribology

Abstract

ABSTRACTIon implantation into steels with a martensitic microstracture is reviewed and discussed in terms of different implanted species and observed changes in the structure. Both single ion and dual ion implantation treatment are included. The disability of the nitrogen ion implantation to improve the tribological characteristics of steels with a martensitic microstructure can be overcome by dual implantation of titanium and carbon, for example. Results of tribological tests on samples in which titanium is replaced by chromium are more controversial, although changes in the sliding characteristics were observed. Dry sliding on the samples implanted up to 1018 ions/cm2 is totally different by nature and -based on the reported results- associated with the formation of carbon precipitates on the surface. The thermal stability of implanted nitrogen and carbon in MЗ high-speed steel was examined and nitrogen was shown to be less stable than carbon. Mechanical and tribological properties were further changed by heat treatment after ion implantation, which indicates that temperature is also a critical parameter during ion implantation.