DOUBLE-LAYER POROUS METAL CATHODE Russian patent published in 2023 - IPC H01J9/04 H01J1/02 

FIELD: electronic engineering.

SUBSTANCE: invention relates in particular to metal-porous cathodes (MPC) of microwave electronic devices with increased current load and increased service life. A two-layer sponge is installed in the end part of the MPC, made in form of a body of molybdenum, in which the main layer with an emitting surface with a density of (78-80)% consists of a mixture of Ir, Cr₂O₃ and W powders in the following composition: (65±5)% by weight of Ir+(10±2)% by weight of Cr₂O₃+(25±5)% of W and impregnated with an active substance based on BaO, CaO and Al₂O₃, having an evaporation rate lower than the evaporation rate of the active substance of the second, feeding layer (for example, with composition 5ВаО⋅3СаО⋅2Al₂O₃). The feed layer with a density of (60-65)% consists of powder W and is impregnated with an active substance that additionally contains chromium oxide (for example, composition 3ВаО⋅0,5СаО⋅Al₂O₃⋅0.3 Cr₂O₃). On the specified two-layer sponge there is a film made of Ir, Cr and W in the following composition: (65±5)% by weight of Ir+(10±2)% by weight of Cr+(25±5)% of W with thickness (0.8÷1.0) mcm.

EFFECT: increase in the emissivity of the MPC with its high durability.

3 cl, 2 dwg