A STUDY OF ADSORPTION AND DIFFUSION OF HYDROGEN IN THE AUSTBNITIC STAINLESS STEEL BY AP-FIM

Hydrogen adsorption and diffusion on the surface of austenitic stainless steel are studied with atom probe field ion microscope (AP-FIM). Hydrogen is noticeably adsorbed on the surface at low temperature (85K) and diffuses into the bulk to a depth of about 40 atom layers . The diffusion activation energy is calculated to be 0.22eV ( or 21.2KJ/mol). It is also found that the microstructure of a specimen charged with hydrogen is changed, and the distribution of hydrogen fluctuates with the depth.