Low Temperature Synthesis of α-Alumina with a Seeding Technique. (5th November 2013)

• Record Type: Journal Article
• Authors: Inoue, Kazuhiro; Hama, Masachika; Kobayashi, Yoshio; Yasuda, Yusuke; Morita, Toshiaki
• Other Names: Bing K. L. Academic Editor.; Jia D. Academic Editor.; Oh W.-C. Academic Editor.; Tuan W.-H. Academic Editor.
• Is Part Of: ISRN ceramics. Volume 2013(2013)
• Publication Date: 2013-11-05
• Subjects: Ceramics -- Periodicals; Ceramics; Electronic journals; Periodicals; 666
• DOI: 10.1155/2013/317830
• Languages: English
• ISSNs: 2090-7494

Abstract

Abstract : This paper reports a method for producing α -Al2 O3 at low temperature, which uses a seeding technique. White precipitate of aluminum hydroxide, which was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution, was peptized by using acetic acid at room temperature and then transformed to a transparent alumina sol. To the alumina sol α -Al2 O3 particles were added as a seed, and then the sol containing α -Al2 O3 particles was transformed to an α -Al2 O3 -seeded alumina gel by drying the sol at room temperature. The nonseeded alumina gel was amorphous or fine crystallites even after being annealed at 600°C and was crystallized to γ -Al2 O3 at 700°C. The α -Al2 O3 seeding promoted crystallization of alumina gel to α -Al2 O3 . The promotion of crystallization was made remarkable with a decrease in α -Al2 O3 particle size and an increase in α -Al2 O3 particle content in weight for the final seeded alumina gel. With an α -Al2 O3 particle size of 150 nm and an α -Al2 O3 particle content of 5%, the seeded alumina gel was partially crystallized to α -Al2 O3 by annealing at a temperature as low as 700°C and mostly at 900°C.