Direct heating cathode and process for producing such

Abstract

A direct heating cathode for electron guns and a process for producing such a cathode are disclosed. The above direct heating cathode achieves a high current density, extends the expected life span and simplifies the cathode producing process. In the process for producing the above cathode, powdered iridium (Ir) as a basic ingredient is mixed with powdered cerium (Ce) as a subsidiary ingredient at a given mixing ratio into a powdered metal mixture. The powdered metal mixture in turn is applied with a mechanical impact through high energy ball milling, thereby being mechanically alloyed into alloy powder. The alloy powder is compressed with a given pressure, thereby being formed into an alloy pellet. The alloy pellet in turn is heated to remove residual gases from the pellet. Thereafter, the electron emitting performance of the pellet is tested.