| 摘要 |
<p>PURPOSE:To maintain good electric insulation between a cathode and a heater, and good electron emission characteristic for a long period of time by covering an impregnated cathode pellet, excluding its electron emission surface, with a heat-resistant metal suppression layer integrated with the cathode pellet. CONSTITUTION:Pellets formed by impregnating porous sintered bodies 11, 21 with electron emission substance 12 and 22 composed of 4Ba O . CaO . Al2O3 are prepared and to W suppression layers 13 and 23 in Ar. Then, Mo-Ru eutectic fine powder pasted with butyl carbitol acetate is applied to the W layer 13 to be combined with a Mo sleeve 14 and subjected to an instantaneous high temperature heating in H2 to deposit the pellet and the sleeve to each other with wax material 15 wetting the W layer surface 13 evenly. When a cup-shaped W barrier layer 27 is used, a porous W pellet is inserted after the wax material 25 is applied to its inner surface, the wax material 25 is then applied to the upper inner surface of Mo sleeve 24, and the pellet and the barrier layer 27 are inserted and subjected to an instantaneous high temperature heating to be integrated. With this constitution, an impregnated cathode with high reliability can be obtained.</p> |
