Hydrogen in Bulk Metallic Glasses: Storage Potential and Effects on Structure

摘要

Several new ferrous and no-ferrous compositions that are capable of forming metallic glasses in bulk form have been examined for their potential to reversibly ingest hydrogen and discharge it. Hydrogen charging was done both by gas charging at pressure and temperature and by the electrochemical route. Results from both approaches were in good agreement and showed that the Fe-based and Y-based glasses were not capable of ingesting hydrogen whereas the Zr-based and Cu-based glasses could take in an appreciable amount of hydrogen but were incapable of discharging it. The hydrogen in the latter alloys interfered with the crystallization process upon heating. The residual hydrogen in the material however served as a qualitative probe for determining possible structural variations in the glass from the inside to the outside. Specifically, calorimetric scans of hydrogen-charged specimens extracted from the center of the ingot were visibly different from those obtained from the edge, suggesting that the structure was more relaxed in the central portion of the ingot. Calorimetric scans of the Zr-based glass at various rates from 0.1 degrees Celsius/min-100 degrees Celsius/min confirmed a strong heating rate dependence of the glass transition temperature and the crystallization response, the effect being more dramatic in the 0.1 degrees Celsius/min-10 degrees Celsius/min regime.