The metallurgical properties of tungsten–iridium cathodes

The results of an investigation of the effects of fabrication parameters in die-pressing of tungsten–iridium cathode matrix materials up to f 0.130 in. 3.3 mm.in diameter are reported. Tungsten–iridium matrix cathodes offer important performance advantages over ‘M’ cathodes, but their performance has often been erratic and unpredictable. This investigation relies on use of metallographic techniques to easily observe and characterize microstructural properties, such as pore size, distribution and density, as well as area and distribution of different phases. Data and micrographs are presented for five cathode matrix variants, along with limited emission testing results. q1999 Published by Elsevier Science B.V. All rights reserved.