| 摘要 |
PURPOSE:To enhance roundness by inserting a columnar or cylindrical jig which has an outer diameter of nearly same dimension as the inner diameter after shrinkage due to sintering of a molded cylindrical ceramics body and is tapered in the axial direction into the inside of the same. CONSTITUTION:Slurry is obtained by adding a binder such as methyl cellulose and PVA and the prescribed amount of a sintering adjuvant such as boron and carbon to the fine ceramics powder such as SiC and furthermore adding water and thereafter sufficiently mixing the mixture. Then this slurry is treated by a spray dryer and granulated and thereafter pressurized to obtain a molded cylindrical body. Graphite powder 6 is arranged between the molded cylindrical ceramics bodies 1 and these bodies 1 are overlapped in two-steps and provided on a setter 4 made of a graphite plate. Furthermore a jig 3 for sintering which is tapered at about 0.5/1000-1/1000 in the axial direction is arranged in the center of the central part 2 of the molded body 1 on the setter 4. A sintered cylindrical ceramics body is obtained by sintering the molded body 1 at 1900-2100 deg.C for 2-3 hours. |
