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The mullite-zirconia composites were prepared by reaction-sintering of alumina and zircon powder. Besides, the slip casting method was employed for fabrication of these composites. Then, the effect of nano-TiO2 addition on the properties of these composites was investigated and the results were compared with micro-sized TiO2. Hence, the physical properties, phase composition, flexural strength and microstructure of these composites after firing at 1600°C were studied. The results showed that the flexural strength of composite tends to increase with the addition of 0.5 wt.% nano-TiO2. It is attributed to the formation of larger size rod-like ZrO2 and enhanced ceramic bonding between them

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In this paper, the effect of MgCl2 addition on the sintering behavior of MgAl2O4 spinel produced via oxide mixture method was investigated. For this reason, the stoichiometric mixture of magnesite and calcined alumina as raw materials was calcined at 1100?C. The calcined mixture was milled, pressed and then, fired at 1300 and 1500?C after addition of various amounts of MgCl2. Besides, the physical properties, phase composition and microstructure of fired samples were investigated. The results showed that MgCl2 addition has great effect on the densification and particle size of spinel. Besides, MgCl2 addition increases the amount of spinel phase at all firing temperatures. Due to the decomposition of MgCl2 and then formation of ultra-fine MgO particles, the nano-sized spinel is formed on the surface of the larger spinel particles.