Preparation Method of Submicrometer-Sized α-Alumina by Surface Modification of γ-Alumina with Alumina Sol

• Published in: Journal of the American Ceramic Society 2000-04, Vol.83 (4), p.750-754
• Main Authors: Han, Kyoung R., Lim, Chang Sup, Hong, Mee-Jeong, Jang, Jin Wook, Hong, Kug Sun
• Format: Article
• Language: English
• Subjects: alumina; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Powders; surface
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2000.tb01269.x

A method is introduced to prepare almost‐spherical submicrometer‐sized α‐alumina via surface modification of γ‐alumina with an alumina sol. Milled γ‐alumina, in the presence of 3 wt% of α‐alumina with a median particle size (d50) of 0.32 μm (AKP‐30), produced irregularly shaped α‐alumina with d50∼0.3 μm after heat treatment at 1100°C for 1 h. γ‐alumina that had been surface‐modified by milling in the presence of 3 wt% of the alumina sol resulted in almost‐monosized, spherical α‐alumina ∼0.3 μm in size after heat treatment at 1100°C for 1 h. Furthermore, almost‐spherical α‐alumina 0.1—0.2 μm in size was obtained by milling γ‐alumina with 3 wt% of AKP‐30 alumina in the presence of 3 wt% of the alumina sol, followed by heat treatment at 1100°C for 1 h. The alumina sol that has been introduced in this work seems to act as a dispersant, in addition to helping to form a spherical shape.