Microstructural Characterization of Reactively Sintered Mullites |
| |
Authors: | Ferhat Kara Servet Turan John A. Little Kevin M. Knowles |
| |
Affiliation: | Department of Ceramic Engineering, Anadolu University, Iki Eylül Kampüsü, 26470 Eskişehir, Turkey;Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ, United Kingdom |
| |
Abstract: | Mullite ceramics have been produced by reaction sintering of powders prepared using pseudoboehmite–colloidal silica and aluminum sulfate–colloidal silica mixtures. The microstructural development of these mullites was studied by a number of transmission electron microscopy based techniques including diffuse dark field, Fresnel fringe defocus imaging, and high-resolution transmission electron microscopy. This characterization procedure showed that mullite ceramics free from glassy phases at triple junctions and grain boundaries could be produced from both mixtures using suitable sintering temperatures and alumina/silica ratios. The wetting of grain boundaries by glass, occurring in the mullite ceramics from either incomplete reaction between alumina and silica components or release of silica from the mullite structure with increasing temperature, was found to depend on the prior thermal history of the ceramics. |
| |
Keywords: | microstructure sintering mullite |
|
|