Aluminum is a typical metal with a quick and self-healing passivation course. The dense oxidation film effectively prevents aluminum from being continuously oxidized by oxygen or water vapor. In this study, we report a kind of aluminum alloy powders that shows popcorn-like shape transformation in the reaction with low-temperature water vapor, which demonstrates that circumventing the passivation of aluminum alloy through the self-sustaining shape changes in hydrolysis reaction can become a reality. In-situ experiments disclosed that the hydrogen-assisted cracking and the interfacial corrosion play important roles in facilitating aluminum reactivity and cause a popcorn-like shape transformation. Moreover, the amorphous hydrated layer may enhance water transportation through the oxidation layer by the ‘spongy’ behavior. This study reveals a special corrosion mechanism of aluminum and provides a promising perspective of using aluminum in the energy field.
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