Treatment of refractory metals by high temperature plasma based ion implantation

Full text: High temperature plasma based ion implantation (HTPBII) has been successfully used to treat metals and metal alloys in the plasma laboratory at INPE. The heating, performed with electron bombardment during the off time of the high negative voltage pulse, allow a precise control of the temperature of the substrate during nitrogen ion implantation and is a key point to achieve thick modified layers on the surface of the treated specimens. The latest results concerning significant improvements of mechanical and tribological properties of Nb, Mo, Ta and W, will be presented. In addition, a complete set of characterization will performed by X-Ray diffraction, Scanning Electron Microscopy and Glow Discharge Optical Emission Spectroscopy, in order to identify the new phases produced after treatment, as well as the changes of the morphology of the surfaces and the elemental depth profiles, respectively. (author)