NITROGEN PLASMA SOURCE ION-IMPLANTATION OF ALUMINUM

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