| 摘要 |
<p>PURPOSE:To improve facility of a coated layer and a reactive barrier layer, and to improve reliability by fitting the large outer peripheral base part of a negative electrode chip consisting of thermionic radiation material of LaB6 on a support made of metal of high melting point. CONSTITUTION:A negative electrode chip 4 has a coaxial shape made of LaB6, and the maximum diameter of its base part is larger than that of the other parts. A paste-like reactive barrier layer cursor, for which colloidal carbon powder and Ti powder are blended together at the ratio of 5:1 in volume, is applied to the base part of the negative electrode chip 4 in a coaxial shape support body 5 made of metal of high melting point such as Ta, and is inserted therein, and is tentatively stopped. Ta powder dispersed in water is applied from the end part of the support body 5, and is dried, and the gap between the chip 4 and the support body 5 is filled with Ta powder. A metal heating element 3 is welded to the support body 5, and is heated in vacuum to form a reactive barrier layer 6 and a sealed layer 7 consisting of Ta sintered body, and the gap between the chip 4 and the support body 5 is sealed.</p> |
