| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a production method of a polycrystalline ceramic body with excellent density relating to a production method of a polycrystalline body composed of ceramics. <P>SOLUTION: A preparation step, a mixing step, a forming step and a heat-treating step are performed. In the preparation step, a coarse particle ceramic powder composed of the ceramics, and a fine particle powder having an average particle diameter of ≤1/3 the average particle diameter of the coarse particle ceramic powder are prepared. In the mixing step, the coarse particle ceramic powder and the fine particle powder are mixed to produce a raw material mixture. In the forming step, the raw material mixture is formed to a shaped body. In the heat-treating step, the shaped body is heated and thereby sintered to produce the polycrystalline ceramic body. In the heat-treating step, a temperature elevating process and a first holding process are performed and at the same time, a second holding process and/or a cooling process are performed. In the temperature elevating process, heating is started to elevate the temperature and in the first holding process, the shaped body is held at a temperature T1°C. In the second holding process, the shaped body is held at a temperature T2°C. lower than the temperature T1°C. In the cooling process, the shaped body is cooled at a temperature dropping rate of ≤60°C/h or less from the temperature T1°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
