Comparative study of hydrogen uptake and diffusion in ODS steels

In this work EUROFER 97, ODS-EUROFER, and PM2000 steels are studied in terms of their interaction with hydrogen at ambient temperature. Hydrogen uptake and effective activation energy of its diffusion and trapping are calculated from the thermal desorption spectra obtained for the studied steels in the temperature interval up to 1123 K after the electrochemical hydrogen charging. It was observed that hydrogen uptake in ODS-EUROFER and PM2000 is markedly higher than in EUROFER 97 steel. It is shown that hydrogen in ODS-EUROFER has the effective diffusion activation energy, which is 0.08 and 0.06 eV larger than that in EUROFER 97 and PM2000, respectively. The high-temperature components of the TDS peaks in the studied ODS steels are suggested to reflect hydrogen de-trapping from the oxide nanoparticles. The mean particle size, the size distribution and chemical composition are studied using SEM and TEM techniques.