. . . . . . . . . .    ANM 2010     3rd International Conference on Advanced Nano Materials     12-15 September 2010 - Agadir, Morocco Back    Abstract ANMM197 COMBUSTION SYNTHESIS OF MAGNESIUM ALUMINATE SPINEL POWDERS FOR IMPROVED DENSIFICATION Tiago Vieira da Silva, Augusto Barros Lopes, Ana Maria Segadães University of Aveiro, Dept. Ceramics and Glass Eng. (CICECO), 3810-193 Aveiro, Portugal . Magnesium aluminate (MgAl2O4) spinel is known for high mechanical strength and refractoriness associated with excellent ultraviolet to infrared light transmittance, which make the corresponding polycrystalline ceramics very attractive for transparent armor and visible-infrared windows. However, direct fabrication of dense magnesium aluminate spinel ceramics from mixtures of alumina and magnesia is rather difficult, due to the near 5% volume expansion that occurs during the spinel formation. To overcome this limitation, pre-reacted spinel powders are sintered, ususally at very high temperature, seeking full densification of the resulting ceramic. Given that both sintering conditions and densification degree strongly depend on the starting powders reactivity, alternative synthesis methods have been sought. This work presents results from an investigation on the combustion synthesis of magnesium aluminate spinel powders and shows the effect of synthesis temperature and reactants proportions on the characteristics of the resulting spinel powders. The experimental results obtained by X-ray diffraction, thermal analysis, particle size, particle morphology and crystallinity (SEM, TEM) showed the influence of the reaction parameters on the powder characteristics and how the latter affected the densification behaviour. . © nanoAC . . . . . . . . . .

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