Abstract

A formation of aluminum hydroxide by hydrolysis reaction in the water has been studied by using nano aluminum powder fabricated by pulsed wire evaporation(PWE) method. The hydroxide type and morphology depending on temperature and pH were examined by structural analysis. The Boehmite(Al_2O_3.H_2O or AIO(OH)) was predominantly formed in high temperature region over 40°C, while the Bayerite(Al_2O_3.H_2O or Al(OH)_3) below 30°C of hydrolysis temperature. The Boehmite formation was preferred to the Bayerite in acidic solution in the same hydrolysis temperature. The slowly formed Bayerite phase showed facet crystalline structure, while the fast formed Boehmite was fine fiber with a large aspect ratio of several nm in diameter and several hundred nm in length, and with much larger specific surface area(SSA) than that of Bayerite. The highest SSA was about 420m2/g.

• Keywords: Bayerite;beta-Al(OH)_3, Boehmite;gamma-AlOOH;