Observation of sintering behavior and grain growth in gel-cast method for near net shape

The sintering shrinkage behavior of gel-cast body was studied to be clarify what has influence to the green property, and causes the deformation in sintering, beside the slurry property in gel-casting method. The alumina sintered body was fabricated by gel-cast method. The two type mold, Flat-mold and Vertical-mold, were used for investigating the difference between the outside, central, upper and bottom of the sintered body. The measurement of sintering shrinkage shows that sintering shrinkage occurred toward the center. And, from the observation of cross-section SEM in sintered body, there were long grains along the mold wall in Flat-mold, and the grain size was larger in bottom of the body in Vertical-mold. It is suggested that the effect of interaction from the mold-wall, and effect of sedimentation causes the deformation of sintered body.