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.Theeffect 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 fromacidic 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, themechanochemically 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.
