*Member, The American Ceramic Society.
Formation of Ceramics from Metakaolin-Based Geopolymers. Part II: K-Based Geopolymer
Article first published online: 16 MAR 2009
© 2009 The University of Illinois at Urbana-Champaign
Journal of the American Ceramic Society
Volume 92, Issue 3, pages 607–615, March 2009
How to Cite
Bell, J. L., Driemeyer, P. E. and Kriven, W. M. (2009), Formation of Ceramics from Metakaolin-Based Geopolymers. Part II: K-Based Geopolymer. Journal of the American Ceramic Society, 92: 607–615. doi: 10.1111/j.1551-2916.2008.02922.x
C. Jantzen—contributing editor
This work was supported by Air Force Office of Scientific Research (AFOSR), USAF, under Nanoinitiative Grant No. FA9550-06-1-0221, through Dr. Joan Fuller.
- Issue published online: 16 MAR 2009
- Article first published online: 16 MAR 2009
- Manuscript No. 25058. Received July 31, 2008; approved December 3, 2008.
The structural evolution and crystallization of potassium-based geopolymer (K2O·Al2O3·4SiO2·11H2O) on heating was studied by a variety of techniques. On heating from 850–1100°C, potassium-geopolymer underwent significant shrinkage and surface area reduction due to viscous sintering. Small, 15–20 nm sized precipitates present in the unheated geopolymer coarsened substantially in samples heated between 900° and 1000°C. However, the microstructural surface texture was dependent on the calcination conditions. Leucite crystallized as the major phase after being heated to >1000°C, although a minor amount of kalsilite was also formed. Prolonged heating for 24 h at 1000°C led to the formation of ∼80 wt% of leucite, along with 20 wt% of remnant glassy phase. The surface of geopolymers heated to 1000°C attained a smooth, glassy texture, although closed porosity persisted until 1100°C. Thermal shrinkage was completed by 1100°C, and the material reached 99.7% of the theoretical density of tetragonal leucite.