| 摘要 |
PURPOSE: To obtain a sintered material having uniform composition by forming a gap between a firing ceramic capsule and a lid for covering the capsule using a gap-opening and closing means made of a material having a linear expansion coefficient smaller than that of the firing capsule. CONSTITUTION: A ceramic material to be fired is placed in a holding part 1a and covered with a lid 3 by fitting the grooves 3a of the lid 3 to the tip ends of supporting members 2 formed on four corners of a firing capsule 1 to form a gap between the firing capsule 1 and the lid 3. When the firing jig is fired, the thermal decomposition of a polymer binder in the firing ceramic takes place at about 200-400 deg.C while keeping the gap as it is in the above temperature range to release the decomposition gas to the outer atmosphere through the gap and prevent the stuffing with the decomposition gas. When the firing temperature reaches about >=500 deg.C, the firing capsule 1 is relatively expanded by the thermal expansion coefficient difference between the firing capsule 1 and the supporting member 2 to narrow and finally close the gap. The space in the firing capsule 1 is maintained to a definite atmosphere thereafter to obtain a sintered ceramic material having uniform composition. |
