Activation Energy for the Corrosion of Aluminum Powders in Water

摘要

The self passivation of aluminum in water generally prevents the generation of hydrogen from an aluminum-water reaction, in conditions preferred for portable systems. However, the potential for corroding aluminum to produce quantities of hydrogen at a lower total system mass compared to compressed storage tanks is spurring research into accelerating aluminum corrosion by ball milling, and mixing with other powders. This allows commercially useful amounts of hydrogen to be generated at moderate temperatures and neutral pH regions. To further study the mechanism behind the increased rate, the activation energies were calculated for hydrogen evolution from pure aluminum, aluminum that had been ball milled, and aluminum mixed with alumina powder. Overall, aluminum that is in contact with higher amounts of aluminum hydroxide, either grown or added, showed a drop in activation energy from approximately 80 kJ/mole down to 24 kJ/mole.