THIN-LAYER ACTIVATION-BASED EVALUATION OF TRIBOLOGICAL BEHAVIOR OF LIGHT ION-IMPLANTED METALLIC SAMPLES

In our Cyclotron Laboratory wear and/or corrosion studies of metallic machine parts are performed on a routine basis by using the Charged Pa rticle Surface Activation method, also commonly known as the Thin Laye r Activation (TLA) technique. In principle, this method consists of an ion beam irradiation of the surface of interest (typically using prot on and deuteron beams), followed by in-situ radioactivity monitoring, on a testing bench or in normal running conditions. The observed chang es in radioactivity are then transformed in mass losses, by using a sp ecific calibration procedure. In spite of the high reliability of the method, which allows fast and accurate determinations under real opera ting conditions, the issue of possible influence of ion bombardment up on the tribologic properties of irradiated components had yet to be cl arified. To do that, a dedicated set-up was designed so as to ensure a simultaneous irradiation of the disk-shaped samples at various incide nt beam energies and doses. Since the expected structural modification s were associated not only to ion-induced damages, but also to the loc al heating, we tried to outline the contribution of each of the two ab ove-mentioned effects. Consequently, the microstructure effects have b een investigated by both electronic and metallography microscopy. The Vickers micro-hardness test has been taken before and after irradiatio n of each sample. Two main outcomes can be reported: the use of radioa ctive labelling for wear and corrosion control using MeV beams with do ses below 10(17) ions/cm(2) of light particles such as protons and deu terons does not lead to significant changes of the tribologic properti es of the studied machine part; and besides, wear diagrams (wear level s vs, running time) for Carbon Steel Alloy (OL-45 in Romanian standard , 0.45% carbon) and Cu-63/Zn-37 brass irradiated at different doses (1 0(17)-10(18) ions/cm(2)) have been obtained.