Effects of ion implantation on nitriding metal by the plasma source nitriding

The effects of ion implantation and the subsequent surface nitriding treatment on the formation of hardened surface-layers in aluminum have been investigated. As the pre-treatment, ion implantation was carried out with D2+0, N2+, Ti+, Cr+, Ni+ and ions at 25 keV in the ion dose range from 7 x 1014 to 8 x 1019 ions cm-2. Subsequently, nitriding treatment by means of 'plasma source nitriding' was performed at a temperature of 3250C for 4 h. As the result, the hardened layers were formed successfully on the surface of aluminum. The maximum ratio of increased hardness in modified aluminum to raw aluminum was about three by the pre-implantation of N2+, Ti+ or Mo+ ions. The thickness of the hardened layers varied with the ion species and the ion doses. The maximum thickness reached was about 1mm (or more) with Mo+ ions at a dose of 3 x 1015 ions cm-2. (author)