Insight into the reactivity of Al–Ga–In–Sn alloy with water

An Al alloy ribbon with finer Al grains was prepared using a rapid spinning technique, and then was annealed at different temperatures to modify its microstructures, such as: Al grain size, size and number of Ga–In–Sn phase. The microstructures and phase compositions of the as-prepared and those annealed ribbons were investigated by means of XRD and SEM/EDX. The reaction of Al and the grain boundary phase was measured using DSC. Based on DSC analysis and other experiments, the formation of Al–Ga–In–Sn eutectic was suggested the origin of the alloy being capable of splitting water. Kinetic measurements found that the H2 generation rate depends strongly on the microstructures of ribbons. An analytical expression was established to calculate the H2 generation rates of ribbons with the measured microstructure parameters, and the calculated results agreed well with measurements.

► Al grain size, and the size and number of Ga–In–Sn particles are key factors that influence the reaction rate of Al with water.
► A higher H2 generation rate can be obtained by modifying the microstructures of Al alloys.
► The reaction of Al and Ga–In–Sn to form quaternary eutectic should be the origin of Al alloy being capable of splitting water.