Microstructure and Mechanical Properties of Hot-Pressed α-Al2O3-Seeded -Alumina Ceramics
Source: International Journal of Applied Ceramic Technology, Volume 4, Number 3, July 2007 , pp. 276-284(9)
Abstract:High-quality alumina ceramics were fabricated by a hot pressing with MgO and SiO2 as additives using α-Al2O3-seeded nanocrystalline -Al2O3 powders as the raw material. Densification behavior, microstructure evolution, and mechanical properties of alumina were investigated from 1250°C to 1450°C. The seeded -Al2O3 sintered to 98% relative density at 1300°C. Obvious grain growth was observed at 1400°C and plate-like grains formed at 1450°C. For the 1350°C hot-pressed alumina ceramics, the grain boundary regions were generally clean. Spinel and mullite formed in the triple-grain junction regions. The bending strength and fracture toughness were 565 MPa and 4.5 MPa·m1/2, respectively. For the 1300°C sintered alumina ceramics, the corresponding values were 492 MPa and 4.9 MPa·m1/2.
Document Type: Research Article
Affiliations: 1: State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China 2: Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
Publication date: July 1, 2007