NITROGEN PLASMA SOURCE ION-IMPLANTATION OF ALUMINUM

Nitrogen plasma source ion implantation has been applied to pure aluminum and aluminum alloy 7075 (Al-Cu-Mg-Zn). Nitrogen implantation modified the surface properties through transformation of the surface to aluminum-nitride (AlN). A uniformly thick (approximately 0.15 mum), polycrystalline (approximately 30 nm grain size) and continuous AlN layer was formed on both pure aluminum and 7075. Knoop microhardness tests showed an increase in surface hardness at low loads. Pin-on-disk wear tests showed nitrogen implantation decreased the wear rates by a factor of approximately 10 for alloy 7075. This study demonstrates significant modification of the tribological properties of an aluminum surface can be accomplished using nitrogen plasma source ion implantation.