FILAMENT FOR HEATING CATHODE AND ITS MANUFACTURING

摘要

PURPOSE:To reinforce a filament by embodying silicone carbide (SiC) fibers in a material for the filament for heating a cathode. CONSTITUTION:A powder mixture comprising 30wt% of W powder and 70wt% of Ni powder is flame sprayed on a molybdenum plate 21 by plasma flame spray method to form a W-Ni alloy layer 22. Then the surface of the W-Ni alloy layer 22 is lapped, and silicon carbide (SiC) bifers 231 with a diameter of about 10muphi are aligned along the longitudinal direction. Then a powder mixture the mixing ratio of which is the same as that of the previous powder is flame sprayed by plasma flame spray method to form an alloy layer 24, and the surface is lapped. This process is repeated several times to form a plate material 25, then the plate material 25 is soaked in a nitric acid to dissolve the molybdenum plate 21, and it is high accuracy-rolled to obtain a mother material for filaments. The mother material is cut so that the longitudinal direction of the SiC fibers coincides with the longitudinal direction of the filament. Thus the filament can be reinforced.