A new nickel matrix cathode

A new nickel matrix cathode with rather unusual electrical, mechanical and chemical behavior has been developed. It is capable of delivering DC emission for extended periods in the high current density range. For example, it has yielded 10 amps/cm²space charge limited current at 1050° B for test periods of up to several hours and 4 amps/cm²at 950° B for test periods of up to 400 hours. It will also deliver 1 amp/cm²at roughly 100° C lower temperature than the barium aluminate impregnated tungsten matrix cathode and has done so for periods currently up to 6000 hours. In contrast to other matrix cathodes, this will also yield current densities at low temperatures that are comparable to oxide coated cathodes, e.g., 200-300 ma/cm²at 750° B. Evidence of more uniform emission than has been possible with a previous design nickel matrix cathode will be shown by Child´s law plots.