IMPREGNATION TYPE CATHODE BODY STRUCTURE

摘要

PURPOSE: To retard drop in electron emission characteristics of an impregnation type cathode body structure caused by moisture. CONSTITUTION: An electron emission material 14 containing an oxide whose main component is barium is impregnated in a disk-shaped substrate 11 made of porous tungsten. The substrate 11 is treated in a carbon dioxide atmosphere to form a carbonate-rich layer 15 on the surface of the electron emission material 14. By the carbonate stable to moisture, conversion of the oxide of the electron emission material 14 into an hydroxide is retarded.