| 摘要 |
PURPOSE:To obtain a cathode structure having a cathode sleeve, only the inner wall of which is blackened, by fitting a base metal into a blackened cathode sleeve, and irradiating laser light on the outer wall of the sleeve in a reducing atmosphere so as to remove or discolor part of a blackened film provided on the outer surface of the sleeve. CONSTITUTION:A cylindrical cathode sleeve member is thermally treated in an atmosphere of hydrogen so as to make a blackened cathode sleeve 22, the inner and the outer walls of which are provided with a blackened film 22a and a blackened film 22b respectively. Next, after a disk-like base metal 21 is pressed and fitted into the upper end of the sleeve 22, the sleeve 22 is irradiated by the first laser light 32 in a reducing atmosphere while being rotated along the axial line 25 of the sleeve 22. At the same time, the second laser light 34 is irradiated upon a welding part 35 located at almost the center of the contact between the sleeve 22 and the metal 21 fitted into the sleeve 22. Thus, the metal 21 and the sleeve 22 are fixed together, and a blackened film located at desired part of the outer surface of the sleeve 22 is removed. By the means mentioned above, a cathode structure having a blackened cathode sleeve only the inner wall of which is blackened can be easily obtained. |
