Modification of stainless steel and aluminium with pulsed energetic ion beams in the millisecond regime

In this contribution we are reporting about experimental results on the surface treatment of aluminium and stainless steel by pulsed energetic nitrogen and neon ion beam irradiation in the millisecond pulse range. The characterization of the modified near surface layers of stainless steel by GEMS and aluminium by XPS showed that phase transformations, iron nitride and aluminium nitride formation took place. Results of nitrogen depth-profiling by NRA and RES indicate that for stainless steel the diffusion process is depending on the pulse duration and the time between two pulses, and for aluminium on the energy density, respectively. Microscopic investigations of the pulse treated surfaces showed crater formation and in some cases surface melting for both materials. Cross-sectional investigations of irradiated aluminium and stainless steel show the modification of the substructure by subsurface melting and grain refining down to 50 mum and 200 mum below the surface, respectively. Microhardness measurements indicate a hardness increase for most of the treated samples in dependence on the irradiation parameters. (C) 2001 Elsevier Science B.V, All rights reserved.