Surface modifications of ion implanted materials

304 stainless steel, nimonic-90 alloy and aluminium were implanted with 130 keV nitrogen, boron and argon ions at closes ranging from 1 x 10(21) to 2.5 x 10(21) ions m(-2). Strain induced and excess strain-free surfaces were studied following ion implantation The samples were implanted in a varian DF-3000 for 3h at 2 x 10(-6) torr with different ions. The characteristics of the implanted layer and depth profile were investigated by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy Relative Knoop indentations were analysed at different test loads. In all the samples a relative increase in micro-hardness of the near surface is observed ranging between 30% to 200% depending on the implanted ion and applied test load The possible correlation of increase in near surface hardness is attributed to the formation of nitride and boride precipitates and dislocation pinning. Similar findings have been reported by other workers for fluorine implanted 440C steel.