METHOD FOR MANUFACTURING POROUS-METAL CATHODES FROM TUNGSTEN POWDER Russian patent published in 2007 - IPC H01J9/04 

FIELD: electrical engineering; manufacturing porous-metal cathodes for electronic devices.

SUBSTANCE: proposed method for manufacturing porous-metal cathodes from tungsten powder includes step-by-step annealing of source powder at temperature ranging between 1650 and 1750 °C and raised by 25 - 50 °C, crushing of mold, quality control of powder after each annealing step by manufacturing specimen pellet compressed at constant pressure, and measurement of pressure P of air flowing through specimen pellet at P ≤ 0.45 kg/cm² after second annealing stage, these being values of its open void channel in terms of air pressure, compression of pellets from powder obtained, their sintering in acid-free medium, and impregnation of sintered pellets with emission-active material; decision is taken to determine size of void channel till sintering for other pressure value for compression of specimen pellet, construction of calibration line P = f(P_sp), determination of difference between void channel size in sintered and original state using reference curve showing this difference as function of sintering temperature Δ = f(T_sn); compression pressure is chosen from calibration line including reference dependence to obtain desired size of void channel in sintered pellets in terms of air flow pressure P_{sn max} - P_{sn max} by its values in non-sintered pellet within interval of (P_{sn min} - Δ) - (P_{sn max} - Δ), where Δ is difference in sizes of void channel in sintered and original states found from reference dependence; P_sn is largest of open void channels out of set of tungsten frame void channels.

EFFECT: enhanced service life of cathodes and reduced degree of evaporation from them.

1 cl, 3 dwg, 3 tbl