Slip-casting is widely used as one of the shaping methods of ceramics. Gypsum molds used for slip-casting are expendables, and industrial wastes after use. In this work, we attempted to develop alumina mold, which are used as substitute for the gypsum molds. Alumina mold also have heat resistance, therefore, it is applicable for a new manufacturing process, where alumina mold and slip-casted green body are fired together without de-molding. Here, we introduce ceramic mold and sintered alumina bodies made by using the mold.

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The starting materials were mixture of Kaolin, Silica and Oak tree ash and Fe₂O₃ were used as coloring agent. In this study Talc was employed for controlling of glaze viscosity and crystallization. To investigate the effects of the formation of niddle shaped spots and properties of Nogime (_??__??_) Temmoku glazes, different samples were prepared by the contents change of Cao, MgO, Fe₂O₃ and the different firing conditions. Formation mechanism of the niddle shaped brownish yellow spots of nogime temmoku glazes were determined by using XRD and Micro Raman spectroscopy. The viscosity of glaze were obtained by SiGglass 6.0. The Raman analysis showed that there are mixed crystalline phase of diopside and anorthite, indicating that the small amounts of Fe₂O₃ were doped on both crystals resulting the yellowish brown color. In this study the viscosity is a main factor at formation mechanism of nogime temmoku crystals. The viscosity of the niddle shaped yellow crystals and the glaze are compared to confirm the formation mechanism of nogime temmoku glazes. Viscosity showed lower value (1.909) at niddle shaped yellow crystals consist of diopside and anorthite than glaze value (3.247). The crystals of nogime temmoku glazes were formed in vertical direction by the difference of fluidity.

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Slip-casting is an important shaping technique which is often used for the ceramics manufacturing. One of the problems for slip casting is the drying. Long time is required to dry gypsum mold and slip-casted green body, which lower the productivity. Drying technique using microwave heating is expected to shorten the time. As gypsum mold is degraded by heating, heat resistant alumina mold was used for this study. Concurrent drying, where slip-casted green body is dried in the alumina mold without de-molding, by microwave heating was tried. It was successfully demonstrated that 1) concurrent drying is effective to protect the green body from rapid heating, and 2) microwave heating can shorten the drying time.

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