| 摘要 |
PROBLEM TO BE SOLVED: To improve durability by preventing the occurrence of a crack caused by thermal expansion in the vicinity of a connection terminal part 4 formed on the circumferential surface of a rod-like base body formed of a silicon nitride-based ceramics. SOLUTION: A metalized layer 12 comprising a first layer 15 and a second layer 16 on the first layer 15 is formed on the circumferential surface of a base body 1 formed of a silicon nitride-based ceramics. The first layer 15 contains at least one of V, Ti, Mo and Mn as a main constituent, and is improved in wettability, and the second layer 16 is formed of a wax material containing Au and Ni. An interlaid layer 13 of Pt or the like is formed on the second layer 16, a connection terminal 14 formed of an Fe-Ni-Co alloy is mounted on it, and a lead terminal 7 of, for instance, Ni is fixed to the connection terminal 14.
|
