METHANE PLASMA SOURCE ION-IMPLANTATION (PSII) FOR IMPROVEMENT OF TRIBOLOGICAL AND CORROSION PROPERTIES

Although ion implantation of tools is now available on a regular basis, there are still many applications where the method is successful but is not being applied commercially, this generally being due to the cost of the process being significantly higher than the value of the tools to be treated. A new approach currently being tested is Plasma Source Ion Implantation (PSII), this process operating by filling the entire treatment chamber with implantation gas, creating a plasma and injecting the ions from the plasma directly into the workpiece. It eliminates line-of-sight restrictions and the need for sample manipulation, and the entire part to be treated is implanted simultaneously, making the process simpler and more efficient. An approach of this sort might well take ion implantation to the factory floor. In this study, methane Plasma Source Ion Implantation (PSII) was used to implant carbon into type 304 stainless-steel and Ti-6A1-4V. Implantation was carried out at a target bias of - 30 keV. The effects of high voltage repetition rates an implantation structure, wear and corrosion properties were investigated. It was found that the carbon depth profile, the structure and the resultant properties of 304 stainless-steel after implantation are sensitive to the implantation repetition rate. No dependence of either the structure or the extent of improvement of the properties of the Ti-6A1-4V alloy on the implantation repetition rate was observed.