Abstract
To obtain the excellent surface roughness in sinking electrical discharge machining The purpose of this research is the determination of the suitable machining conditions and the confirmation of the material structure at the most optimal amount of Al_2O_3 additive. As a result, ZrO_2-Y_2O_3 substances with or without added Al_2O_3 were obtained the excellent surface roughness in the lower electric current settings. In contrast, ZrO_2-Y_2O_3 with over 20wt% Al_2O_3 showed the negative performance for the surface roughness in higher electric current operation.
