| 摘要 |
PROBLEM TO BE SOLVED: To provide a density of a specific value or above and to improve durability by overlapping ceramic powder and metal powder having melting points of specific values or above, and connecting, molding and sintering them at a high temperature and a high pressure of specific values or above. SOLUTION: Ceramic powder and metal powder having melting points exceeding 2500 deg.C and 2000 deg.C respectively are molded and sintered at the density of 96% or above of the theoretical density under the same conditions as the sintering conditions of diamond, a high temperature of 2000 deg.C or above and a high pressure of 100 MPa or above. A ceramic having a high melting point, a high electron emission capability and low heat conductivity, e.g. LaB6, HfC or HfN, is used at the tip section of a thermoelectron emitting electrode. The remaining section slightly apart from it is made a heat radiation section constituted of a metal having a low thermoelectron emission capability and high heat conductivity, e.g. Ir, Os, W, Ta, Mo or Re. A molded and sintered body provided with the mixed powder of the ceramic powder and metal powder having different thermal expansion coefficients is preferably used, and the shearing stress generated on the faying boundary face at the time of natural cooling is mitigated. |
