TRANSFORMATION EVOLUTION AND INFRARED ABSORPTION SPECTRA OF AMORPHOUS AND CRYSTALLINE NANO-Al2O3 POWDERS

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

141 Scopus Citations
View graph of relations

Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)605-610
Journal / PublicationNanostructured Materials
Volume8
Issue number5
Publication statusPublished - Aug 1997

Abstract

Amorphous and crystalline nano-Al2O3 powders were prepared by direct oxidation and hydrolysis of pure aluminum, respectively. The results by XRD and DTA measurements revealed that after annealing at 1370 K, the evolution in the amorphous nano-Al2O3 powder involved a low temperature relaxation followed by a simple γ- to α- Al2O3 transition. On the other hand, the γ- to θ- to α-Al2O3 transitions occurred in crystalline nano-Al2O3 powder. The infrared absorption spectra (IR) for both nano-powders after annealing at different temperatures were measured. The IR spectrum of the amorphous nano-Al2O3 powder exhibited a very broad and smooth band, without any fine structure in the wave-number range from 400 to 1000 cm-1. This is in contrast to that of crystalline nano-Al2O3 powder. The results mentioned above are discussed with reference to the structure relaxation of amorphous nano-Al2O3 powder and the concept of lattice distortion.