عنوان مقاله English
نویسندگان English
In this paper, polycrystalline yttrium aluminum garnet (YAG) ceramic was fabricated by slip casting using an aqueous mixture of Al2O3 and Y2O3 nano-powders and subsequent pressureless sintering. In order to achieve the best optimized milling time for casting, the stoichiometric ratio of raw powders were mixed in water and ball milled in different time periods ranging from 1 to 20 hr. FE-SEM images and BET test in different durations milling times were performed. The results showed that the best optimized time for achieve de-agglomerated powder mixtures is 16 hours. An optimal amount of dispersant for the suspension was found by measuring viscosity as a function of dispersant concentration. Then the powders were co-dispersed using 0.5 wt. % Tetraethyl Orthosilicate (TEOS) and 1.5 wt. % Dolapix CE64 as sintering aid and dispersant additives, respectively. 70 percent solid loading YAG slurry was prepared in deionized water, milled for different time periods, casted on the alumina molding and sintered at 1710 ˚C for 12 hr. The effect of ball milling time on the relative raw and final density, phase composition and final microstructure of the samples was investigated. The results showed that the samples were prepared by 16 hrs. ball milling time suspensions exhibited higher relative raw and final density and had more uniform microstructure. X-ray patterns showed that all samples were pure YAG phase
کلیدواژهها English