Hydrogen and hydride detection in metallic glasses

Different methods for the detection of hydrogen dissolved in the structure of metallic glasses and the detection of hydrides eventually present in these materials are presented and discussed. It includes a conventional procedure, the electrochemical hydrogen permeation test and two alternative ones: a new method herein named proton elastic recoil track analysis (p-ERTA) and another one based on Hall Effect measurements. These methods were applied in samples of Fe40 Ni38Mo4B18 and Ni81P19 metallic glasses. The electrochemical hydrogen permeation tests were described and discussed based on results of the two metallic glasses used so as to support the results obtained with the new methodologies. The p-ERTA technique was proposed as a combination of two well known and established techniques, namely the elastic recoil detection analysis and the solid state nuclear track detection. It permitted the observation that the spatial localization of hydrogen in the structure of the metallic glass possesses a heterogeneous distribution. The easy-to-perform Hall Effect measurements were useful to detect hydride formation in the structure of a metallic glass and the variation of the hydrogen diffusion coefficient over a wide range of hydrogen concentrations, even in regions where hydrogen-hydrogen interactions are likely to occur.