IMPREGNATION-TYPE CATHODE AND METHOD FOR FABRICATING THE SAME

摘要

PURPOSE: An impregnation-type cathode and method for fabricating the same are provided to stably operate the cathode by avoiding drift of a cut off voltage. CONSTITUTION: An impregnation-type cathode is manufactured by coating black coating material over surface of a metal wire(8). The metal wire(3) is made of molybdenum and has a 0.3mm diameter. The black coating material is made by distributing tungsten of a 0.5μm average particle diameter and alumina of a 0.5μm average particle diameter in 60:40 ratio. The coated metal wire(8) is inserted into an opening of a cathode sleeve(3) and then conducted to deposit the black coating on the inner surface of the sleeve(3). The black coating deposited sleeve(3) is drawn from the metal wire(8). The uncoated metal wire(8) is inserted through the opening of the sleeve(3) and conducted to be annealed.