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Journal of Nanomaterials
Volume 2017 (2017), Article ID 6273095, 14 pages
https://doi.org/10.1155/2017/6273095
Research Article

Effects of Milling pH and Hydrothermal Treatment on Formation of Nanostructured Boehmite Binder for Alumina Extrusion

1Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC, Av. dos Estados 5001, 09210-580 Santo André, SP, Brazil
2Centro Universitário da FEI, Department of Materials Engineering, Av. Humberto Alencar Castelo Branco 3972, 09850-901 São Bernardo do Campo, SP, Brazil

Correspondence should be addressed to Humberto Naoyuki Yoshimura; rb.ude.cbafu@arumihsoy.otrebmuh

Received 27 March 2017; Accepted 31 May 2017; Published 5 July 2017

Academic Editor: Victor M. Castaño

Copyright © 2017 Maurício Batista de Lima et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The in situ formation of nanostructured aluminum hydroxides on the surface of alumina particles, which can work as inorganic binder, was reported in this paper. The effect of the suspension pH during milling of alumina powder and subsequent hydrothermal treatment for the hydroxide formation and microstructure was depicted. Under acidic pH condition, the formation of hydroxides was not observed. When the pH of suspension changed from acidic to basic during milling, bayerite [Al(OH)3] nanoparticles were formed, but only a fraction of this hydroxide was converted to boehmite (AlOOH) during subsequent hydrothermal treatment. The aluminum hydroxide and oxyhydroxide formed in this condition improved the smoothness of extruded rods and the strength of presintered segments. For the powder milled under basic pH condition, the mechanochemically formed bayerite was completely converted into boehmite nanoparticles during the hydrothermal treatment. The presence of boehmite nanoparticles contributed to improving plasticity during extrusion, which allowed the reduction of organic binder and increased the strength of presintered alumina rods.