Thermal Evolution of Alumina Prepared by Sol-Gel Technique

GUILLERMINA URRETAVIZCAYA; CAVALIERI, A.L.; J.M. PORTO LÓPEZ; SOBRADOS, I; SANZ, J

JOURNAL OF MATERIALS SYNTHESIS AND PROCESSING

Springer

Lugar: New York; Año: 1998 vol. 6 p. 1 - 7

1064-7562

The thermal evolution of an alumina gel synthesized by hydrolysis of aluminium alkoxide (sol-gel technique) was studied by thermal analysis (DTA and TGA), X-ray diffraction, FTIR and NMR spectroscopies, and specific surface area measurements. Between 400 and 900°C, γ- and δ-aluminas were formed showing aluminium vacancies preferentially located in tetrahedral sites. The atomic rearrangements produced during α-alumina formation are oriented to the progressive elimination of tetrahedral aluminium in the ultimate phase. The evolution of the specific surface area during heating is explained by changes in structure and microstructure.