Nitrogen ion implantation for improvement of the mechanical surface properties of aluminum

The results of the surface treatment of commercial aluminum by nitrogen ion implantation at 120 keV and implanted fluences ranging from 3×l017 to 1.1×1018 ions/cm2 are reported. The treatment was found to lead to the formation of the hexagonal phase AIN, a decrease in strain and an increase of crystallite sizes. The modification of the surface layer so produced was thought to be a cause of a measured increase in surface microhardness and corresponding decrease in friction coefficient and wear measured in pure methanol. Oxygen found in the surface layers was also thought to play a significant role in determining tribological performance.