STUDY OF SUBSURFACE ZONES INDUCED BY FRICTION AND WEAR USING POSITRON-ANNIHILATION METHOD

The positron annihilation studies of defect profiles in well annealed gold and copper samples whose surfaces were exposed to the friction an d wear processes are presented. In the case of copper samples the defe ct profile was obtained by etching the layers and measuring the linesh ape parameter of annihilation radiation. The defect profile detected i n such a case exhibited the exponential decay dependence. For gold sam ples the concentration of defects in the near surface laying region we n obtained using the monoenergetic positrons. Close to the surface the defect concentration is an order 10(-4) and the type of the defects a s positron traps did not change with the depth.