| 摘要 |
PURPOSE:To obtain a ceramic casting mold having no occurrence of cracks, high strength and excellent durability by making the mold with the material in which ceramic fiber is added to the material for a porous mold. CONSTITUTION:A ceramic casting mold is composed of the material in which ceramic fiber is added to the material for a porous mold. As the material for a porous mold, plaster or foamable acrylic resin, etc. is used. Ceramic fiber is mixed with the material for a porous mold in uniformly dispersed condition. As this ceramic fiber, glass fiber is suitable. For instance, in the ratio of water/ plaster, the material in which 1% of glass fiber 4 is added to 69% of plaster 3, is used. This plaster is poured into a metallic mold, and the plaster body taken out from the metallic mold is dried, whereby the plaster mold (a split mold composed of a top force 1 and a bottom force 2) for casting a disk, is produced. When the sludge of silicon nitride is cast into this plaster mold at 4kg/cm<2> of casting pressure, the plaster mold is not broken and the excellent molded object of silicon nitride may be obtained. |
