Thermionic cathode coating by OMCVD (organo-metallic chemical vapor deposition)

This invention relates to a new and improved thermionic cathode and, more particularly, to a thermionic cathode having a novel coating thereon and to the method of forming the coating. High-power electron-tube devices, such as travelling wave tubes and other microwave generators, require electron emitters or cathodes having very high electron emission densities. For example, emission densities of approximately 15 amperes/2 sq. cm. and greater are required. Failure of the cathode of a tube always results in tube failure. Since cathodes cannot be replaced without rebuilding the entire tube, early failure of a tube's cathode can be a costly event. In many tubes, lifetimes of tens of thousands or more hours must be achieved in order for the tube to an economically viable device.