Effect of air contamination on ball milling and cold rolling of magnesium hydride

In this letter we address the problem of air contamination in high energy milling and cold rolling of magnesium hydride. We found that for short milling time (30 min) milling under argon or air leads to the same crystal structure and same hydrogen sorption behaviour. In the case of the cold rolled sample, the hydrogen sorption behaviour is similar but the crystal structure shows some differences with ball milled samples. As expected, prolonged milling time in air leads to formation of magnesium oxide and degradation of hydrogen sorption capacities. However, kinetics do not seems to show degradation. This investigation shows that, for short milling time, air contamination is not as detrimental as was expected.