IMPLANTATION OF BE-7 RADIOACTIVE-TRACER FOR WEAR MEASUREMENTS OF POLYMERS

A method of indirect activation is proposed to measure the wear resist ance of polymers. This method is based upon the principle of recoil io n implantation, applied to Be-7 radioactive ions generated by He-3 par ticle beams. The radioactive ions are implanted into the near surface (a few micrometres) without degradation of the chemical or mechanical properties of the material. Wear rate of the component is observed via the variation of its activity caused by the loss of material. The act ivity is measured by a gamma ray detector located at a distance from t he implanted sample. We have activated three kinds of polymers (Mylar, polyethylene and polypropylene) and for the first time, determined ra dioactive ion depth distribution. The measured sensitivity is a few hu ndred nanometres. (C) 1998 Elsevier Science B.V. All rights reserved.