Modifying aluminum–water reaction to generate nano-sized aluminum hydroxide particles beside hydrogen

Al–water reaction is used to produce nanoparticles of aluminum hydroxide. Ball-milling of aluminum powder in water was examined for promoting this reaction. Scanning electron microscopy and X-ray diffraction assisted by Rietveld refinement were used to study the by-products of the reaction. Results showed that the activated Al powder completely reacted with water at room temperature. Hydrogen, gibbsite and bayerite were formed at the end of the reaction. A mechanism is proposed to explain how wet milling of Al powder can promote the reaction. The morphology of the by-products changed with the milling time. Notably the samples milled for 7 and 12 h had the shapes of nanospheres, nanospindles and nanorods. The calcination process made in conventional furnace and microwave oven changed the morphology of the produced alumina phases.