The effect of cracks and alloy phase conditions on the hydrolysis characteristics of Al-10Bi alloy powder (composites)

The Al-water reaction has attracted many attentions as it's a convenient method for on-demand hydrogen generation. Although a variety of additives have been demonstrated to promote the activity of Al, the most likely mechanism is simply the inference made from surface conditions and reaction characteristics. In this study, the activation of two kinds of active Al-10Bi alloys powders was prepared by both melting alloy and mechanical alloy methods. The activity of the as obtained powders was analyzed through various methods including XRD, SEM. 3D characterization of active Al powders was conducted using synchrotron X-ray tomography to reveal the inner structure of ball milled active Al alloy powders. Results show that ball milling could effectively introduce a large number of cracks both on the surface and the inner of powders. The number of cracks increased further after adding salt during ball milling. The relation between the inner structure of the Al alloys and their hydrolysis reaction products was also discussed. The specific surface area, the number and distribution of cracks alloy phase are all important factors that influence the hydrolysis reaction of the active alloy powder.