| 摘要 |
PROBLEM TO BE SOLVED: To produce a sintered material having excellent shape accuracy and especially high thermal shock resistance of core material at a low production cost by firing a formed ceramic material loosely put on a columnar core material, wherein the core material is made of a porous ceramic material when the thermal expansion coefficient of the core material is larger than that of the sintered material. SOLUTION: The reason of the use of a porous ceramic material as the core material is that the heating and cooling speed in the firing process can be increased to shorten the firing time and reduce the production cost owing to high thermal shock resistance which is an important characteristic in the case of using the material as a firing jig. The material cost of the core material can be reduced by the use of the porous material compared with a dense material. Furthermore, the weight of the core material can be reduced to reduce the weight load in the collective firing of a number of cores in a continuous firing furnace. The material for the porous ceramic is selected from alumina, zirconia, magnesia, spinel and mullite. The thermal expansion coefficient difference between the core material and the sintered material is preferably >=1.0×10-6/ deg.C. |
