Resistance-to-wear testing of metallic machine components by charged particle surface activation

Surface activation, commonly known as Thin Layer Activation (TLA), is an ion beam technique generally employed for wear and/or corrosion monitoring in industrial plants, especially related to applications in engine and machine construction industries. For an efficient industrial application of this technique, one must foresee some specific irradiation set-ups as well as the measuring method, having in mind the diversity of machine components which might be subjects of such studies and the tribological phenomena involved. Some of these aspects are mentioned the paper. In principle, the TLA-based measuring methods exploit the correlation between the loss of material owing to wear and the resulting changes in radioactivity. Two such measuring methods are derived; they will be reviewed briefly in the paper and illustrated by wear diagrams obtained for several parts of running machines such as piston-rings, linear cylinders and bearing crankshafts, together with a study of characteristics of different (unspecified) lubricant oils. An example where a TLA-based method has been successfully applied, for material couple characterisation on Timken testing stands, is also presented. The paper ends with a typical remnant measuring method application executed for the Romanian Railway Company.