| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 236410 | Powder Technology | 2013 | 8 Pages |
•Reaction of Al with water can be promoted by wet milling of Al powder•The produced aluminum hydroxide includes nanorods with aspect ratio of up to 100, nanoparticles and spindles•Calcination of aluminum hydroxide by either conventional or microwave furnace results in production of nano alumina powder.
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.
Graphical abstractHydrogen and nano-sized aluminum hydroxide were produced by wet milling of an aluminum powder in water. Rietveld refinement of X-ray diffraction patterns shows the presence of gibbsite and byerite phases. Microwave calcination transforms the produced hydroxide phases to alpha and gamma alumina phases. A longer ball milling time results in a faster kinetics of the reactions and finer by products.Figure optionsDownload full-size imageDownload as PowerPoint slide
