Slow Positron Beam Studies of the Stainless Steel Surface Exposed to Sandblasting

The paper presents slow positron beam studies of the stainless steel grade 304 AISI samples annealed in the flow $N_2$ atmosphere and sandblasted under different pressure from 1 to 7 bar. Heating of specimens caused formation of an additional layer on the surface which can be identified as oxides. Sandblasting reduces the thickness of the oxide layer and also defects concentration (vacancies as we suppose) decreases in dependence on pressure applied during blasting. Additionally, the atomic concentrations of oxygen have been obtained using nuclear methods (Rutherford backscattering and nuclear reactions) in the near surface layers of the studied samples.