| 摘要 |
PURPOSE:To manufacture a cathode structure which shows an excellent emission characteristic and in which a base metal plate is efficiently attached to a cathode sleeve without receiving any adverse influence of thermal or mechanical effect. CONSTITUTION:A cathode sleeve 11 made of an Ni-Cr alloy is put in a wet hydrogen furnace with high temperature so as to blacken the surface of the sleeve 1 by selectively oxidizing Cr contained in the alloy. Next, a base metal plate 13 is placed on the sleeve 11 so that a back surface14 of the plate 13, which is not coated with any electron discharging matter, touches an end surface 12 of the sleeve 11. After that, the plate 13 is fixed to the sleeve 11 by subjecting several parts to welding by irradiating laser light from the direction indicated by the arrow of the figure. As a result, an excellent emission can be realized, without causing any thermal influence on the plate 13 and any fear of contaminations of the plate 13, by fixing the plate 13 to the sleeve 11 after the oxidation treatment of the sleeve 11 is performed. |
