| 摘要 |
A joint body formed of a ceramic member composed of a main body (4) and a disclike projection (5), and a ceramic cylindrical body. The disclike projection is inserted inside the cylindrical body, and a relative density of the disclike projection is higher than that of the cylindrical body. The cylindrical body is composed of a straight portion (2d) not contacted by the projection and having a uniform inside diameter, a diameter-expanded portion (2a) in contact with the projection and having the largest inner diameter, and a tapered connecting portion bridging the straight portion and diameter-expanded portion. A difference between the inner diameter of the straight portion and that of the diameter-expanded portion is 0.05 mm to 0.6 mm. <IMAGE> |
