METHOD OF IMPREGNATED CATHODE MANUFACTURE Russian patent published in 2008 - IPC H01J19/20 

FIELD: electricity.

SUBSTANCE: impregnated cathodes are manufactured, which are coated with film of refractory metals with work function that exceeds the one of tungsten free of typical drawbacks of solid or porous films Os, Os-Ir, etc, which consists in significant difference of thermal expansion coefficients and capability of these metal films to form intermetallic compounds with the base (incompatibility). As coating Re is used, which is extruded on the surface of tungsten sponge in the form of small-sized islands with any density of cathode surface filling up to 100%. Tungsten sponge is moistened with rhenium acid (HReO₄), pellet is annealed at the temperature of 1700÷1800°C for 1-2 minutes, this process is repeated more than once, after that it is impregnated with barium aluminate.

EFFECT: cathode work function is improved, and durability at increased temperature is increased.

1 dwg