Passive oxide films on austenite steels (with chromia being major component) render generally high corrosion resistance of these materials in atmospheric air, steam and some acids. At a microscopic level, this resistance depends on the quality of the layers, their tightness, brittleness and recovery processes and to a large degree is influenced by microstructure of the substrate.
The paper presents the results obtained on nanocrystalline austenitic stainless steel processed by High Pressure Torsion (HPT). The aim of the project was to investigate properties of the oxide layers formed on the material subjected to Severe Plastic Deformation (SPD) in comparison to standard micro-metre grain size specimens. To this end AFM investigations have been carried of the surface of specimens subjected to HPT and subsequent annealing. TEM studies of the substrate and measurements of trybological properties have also been made. The results of all these experiments are discussed in terms of the characteristics of nanocrystalline austenitic stainless steels.