| 摘要 |
PURPOSE:To improve the reliability of vacuum seal by a method wherein at first a sealing piece and a glass tube are joined to each other and, after that, electrolytic polishing and nickel plating are applied on the portion of the sealing piece except the joined portion between the sealing piece and the glass tube and finally the sealing piece and a copper tube are joined to each other by brazing. CONSTITUTION:At first a sealing piece 4 and a glass tube 2 are joined to each other. After that, electrolytic polishing is performed under the condition that an oxide film on the portion except the joined portion of the glass tube 2 to the sealing piece 4 of the sealing piece 4 forms an anode in order to remove the oxide film. Further, after nickel plating is applied on said portion so as to increase the wettability by brazing material, the sealing piece 4 and a copper tube 3 are joined to each other by brazing. Due to the structure as mentioned above, the joining of the glass tube 2 and the sealing piece 4, which is the elementary constitution for sealing a vacuum tube 1, and the joining of the sealing piece 4 and the copper tube 3 can easily be done, resulting in enabling to improve the reliability of vacuum seal. |
