Effect of TiO2 in Spinel Formation and Reactive Sintering of Magnesia-rich Ceramics
S. Ghanbarnezhad1, A. Nemati2, M. Bavand-Vandchali3, R. Naghizadeh4
1Solmaz Ghanbarnezhad, Her Department of Materials Engineering, Science & Research Branch, Islamic Azad University, Tehran, Iran.
2Ali Nemati, His Department of Materials Engineering, Science & Research Branch, Islamic Azad University, Tehran, Iran.
3Mohamad Bavand-Vandchali, His Department of Materials Engineering, Science & Research Branch, Islamic Azad University, Tehran, Iran.
4Rahim Naghizadeh, His Department of Metallurgy & Material Engineering, Iran University of Science & Technology (IUST), Tehran, Iran.
Manuscript received on January 20, 2013. | Revised Manuscript received on February 07, 2013. | Manuscript published on February 28, 2013. | PP: 85-87 | Volume-2 Issue-3, February 2013. | Retrieval Number: C1016022313 /2013©BEIESP
Open Access | Ethics and Policies | Cite
© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The solid solubility of magnesia in magnesium -aluminate spinel and magnesium-aluminate spinel in magnesia does not change with temperature thus not creating bonds over periclase grains in single stage sintering process. In the present study, magnesia and alumina powders along with tetravalent oxide (TiO2) additive was analyzed for its role in reactive densification of spinel in single stage firing process in order to achieve a better binding system for magnesia-based refractories. This tetravalent oxide on reaction with magnesia from spinel solid solution with MgAl2O4 as they have similar crystal structure. The spinel solid solution formed using oxide additive is expected to higher solubility in magnesia than magnesium-aluminate spinel, resulting in improvement of the bonding during sintering through increased in solid solubility at elevated temperatures, similar to the complex spinel in magnesia-chrome refractories. The formation of spinel during firing remains as a second phase that retards the grain growth of periclase.
Keywords: Densification, Periclase, Reaction sintering, Spinel Solid solution, tetravalent oxide.