Evaluation of Mechanochemical and Hydrothermal Transformations in a Wet-Milled Alumina by Transmission Electron Microscopy and Thermal Analysis

Abstract:

Milling and hydrothermal treatment of alumina powders in aqueous medium can result in surface transformations generating aluminum hydroxides. The aim of this work was to advance the understanding on these transformations. A α-alumina powder was ball milled in water at different pHs for 10 h, and then autoclaved (150 °C, 3 atm, 3 h). The powders were analyzed by transmission electron microscopy, differential scanning calorimetry simultaneously with thermogravimetry, X-ray diffraction, and infrared spectroscopy. It was observed that milling in basic medium caused the formation of doyleite [Al (OH₃)] nanoparticles, which were fully converted to boehmite (AlOOH) by hydrothermal treatment. The boehmite fraction determined by thermal analysis was 1.7 wt%. The powder milled in acid medium had no mechanochemical and hydrothermal transformations.

• Periodical: Materials Science Forum (Volume 881)
• Pages: 46-51
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.881.46
• Online since: November 2016
• Authors: Humberto Naoyuki Yoshimura, Maurício Batista de Lima, Sydney Ferreira Santos, Fernando dos Santos Ortega
• Keywords: Alumina, Hydrothermal Treatment, Mechanochemical Transformation, Milling

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