Hits:

Indexed by:期刊论文

Date of Publication:2009-04-02

Journal:MATERIALS RESEARCH BULLETIN

Included Journals:SCIE、EI、Scopus

Volume:44

Issue:4

Page Number:785-788

ISSN No.:0025-5408

Key Words:Amorphous materials; Ceramics; Sol-gel chemistry; X-ray diffraction; Thermogravimetric analysis

Abstract:Spherical alpha-alumina powders were prepared by the controlled hydrolysis of aluminum isopropoxide in a hydrolysis system consisting of octanol and acetonitrile. Diverse solvents to dissolve reactant formed diverse hydrolysis systems and affected particle shape of alpha-alumina powders. The precursors crystallized to gamma-alumina at 1000 degrees C and converted to alpha-alumina at 1150 degrees C without intermediate phases. The particle morphology of precursor was retained after it crystallized to alpha-alumina. The heating rate influenced the particle shape and the state of agglomeration during calcination process. The thermal properties of the precursors were characterized by thermal gravimetric and differential thermal analysis. X-ray diffraction technique was used to confirm the conversion of crystalline phase of alumina powders from amorphous to alpha-phase. Transmission electron microscopy was used to investigate the morphologies and size of the precursors and products. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.