Aerosol processing of functionally engineered cermet emitters

Aerosol processing techniques have been used to produce a new type of high conductivity cermet emitter for thermionic cathode application. The versatility afforded by the process has been exploited to engineer a range of variously oriented, interconnected and graded structures within the composite with a view to maximising conductivity whilst minimising the volume fraction of non-emitting metallic phase. Improvements in reliability under high current loading conditions have been obtained without adversely affecting the other emission characteristics of the material.