Hot cathode, its production process and electron tube incorporating such a cathode
AssigneeThomson-CSF
InventorsArvind Shroff, Pierre Palluel
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Abstract
The hot cathode, according to the invention, is constituted by a fritted matrix 1 and a heating filament 4, said matrix being formed from a powder mixture 2 of tungsten and another high work function refractory metal and covered with a high work function refractory metal film 3. FIG. 3.
Claims4
A process for producing a cathode formed from a matrix of a fritted powder metal impregnated with a barium compound, and a heating filament associated with said matrix, wherein the matrix is formed from a mixture of two metals, tungsten and another high work function refractory metal, and wherein the matrix is covered with a high work function refractory metal film, comprising the following successive stages:
- (a) mixing powders of tungsten and another high work function refractory metal
- (b) pressing the mixture between 7 and 10 t/cm.sup.2
- (c) prefritting under hydrogen at between 1100.degree. and 1300.degree. CB for approximately 12 h
- (d) fritting in vacuo at a temperature between 1850 and
- (e) impregnation with calcium and barium aluminates
- (f) elimination of the excess aluminate present on the surface by a chemical process
- (g) deposition of the high work function refractory metal film.
Dependencies are inferred from the claim text.