Control of hydrolytic reaction of aluminum particles for aluminum oxide nanofibers

Al2O3 (alumina) nanofibers have been synthesized by ex situ simple two-step processes consisting of the hydrolysis and dehydration of spherical Al nanoparticles (80–120 nm). The monohydroxide, bohemite AlO(OH) was produced as an end product of hydrolysis and upon subsequent dehydrations, the low temperature phase of bohemite AlO(OH) below 300 °C was completely transformed into the crystalline γ-Al2O3 phase above 420 °C after passing the transition regions of about 350 °C. The produced γ-Al2O3 as well as bohemite AlO(OH) was clearly nano fibrous and co-mingled with the typical diameters of 2–5 nm. A strong dependence of the structural properties of the final Al2O3 on the hydrolytic precipitates is observed, which is explained in terms of the morphological properties interrelated strongly with the phase structure of the end product of hydrolytic reaction.