Showing 3 results for Slip Casting
M. Rahmani, K. Janghorban , S. Otroj,
Volume 33, Issue 1 (7-2014)
Abstract
In this study, the effect of different amounts of Y2O3 on the properties of mullite-zirconia composites was investigated. For this purpose, these composites were fabricated by reaction-sintering of alumina and zircon as raw materials. Besides, the slip casting method was used for forming these composites, and sintering process was carried out at 1600 °C. Then, the physical and mechanical properties, phase composition and the microstructure of these composites were investigated. The results showed that yittria addition up to 0.5 wt.% has no effect on the properties of these composites. Besides, addition of more than 0.5 wt.% yittria formed solid solution with zirconia grains and led to stabilization of tetragonal zirconia phase and increasing of its amount. Hence, yittria addition increases the hardness and bending strength of composite by stabilizing tetragonal zirconia phase and then, decreasing the micro-crack formation during zirconia phase transformation. As results show, addition of 0.75 wt.% yittria leads to a considerable increase in the bending strength.
M. Rahmani, K.janghorban, S. Otroj,
Volume 33, Issue 2 (3-2015)
Abstract
In this study, the effect of different amounts of Y2O3 on the properties of mullite-zirconia composites was
investigated. For this purpose, these composites were fabricated by reaction-sintering of alumina and zircon as raw materials.
Besides, the slip casting method was used for forming these composites, and sintering process was carried out at 1600 °C. Then,
the physical and mechanical properties, phase composition and the microstructure of these composites were investigated. The
results showed that yittria addition up to 0.5 wt.% has no effect on the properties of these composites. Besides, addition of more
than 0.5 wt.% yittria formed solid solution with zirconia grains and led to stabilization of tetragonal zirconia phase and
increasing of its amount. Hence, yittria addition increases the hardness and bending strength of composite by stabilizing
tetragonal zirconia phase and then, decreasing the micro-crack formation during zirconia phase transformation. As results show,
addition of 0.75 wt.% yittria leads to a considerable increase in the bending strength
G. Kafili, B. Movahedi, M. Milani,
Volume 36, Issue 3 (11-2017)
Abstract
In this study, Spark Plasma Sintering (SPS) of both slip casted and powder specimens of alumina/ yttria core-shell nanocomposite were utilized for fabricating transparent Yttrium Aluminum Garnet (YAG) ceramics. Phase evolution, optical transmittance and the microstructure of sintered samples were compared. In slip casting process, Dolapix CE64 was used as a dispersant for preparing the stable aqueous slurry of this nanocomposite powder. The effect of Dolapix concentration and pH value on the stability of the suspension was described, and the viscosity diagrams were investigated at different pH value and different weight percents of Dolapix. The rheological behavior of the nanocomposite powder slipped at 60-70 wt% solid loading was studied by measuring their viscosity and shear stress as a function of shear rate of the slurry. The results showed that, the suspension has a minimum viscosity at pH of 10 by addition of 2.5 wt% Dolapix. Also, the slurry with solid loading of 60 wt% showed the Newtonian behavior and this rheological behavior was preserved even above this solid loading values. Slip casting technique caused the uniform size and pores distribution as well as eliminating large pores in the green body. Consequently, transparent YAG ceramic with 60% optical transmittance was achieved after SPS process of slip casted green body which was much higher than that of nanocomposite powder, i.e. about 30% at the same sintering conditions.
