Controlled porosity sheet for thermionic dispenser cathode and method of manufacture

摘要

A controlled porosity sheet defining a surface for a thermionic dispenser cathode and a method of manufacture. Starting with a generally flat silicon template substrate structure having an array of upstanding microposts 1-25 microns across on 5-100 micron spacings from each other, a layer of metal is deposited on the substrate to surround the microposts and cover the substrate structure to a desired depth. The metal layer is then abraded to a smooth, flat surface which exposes the microposts. Thereafter, the silicon substrate and microposts are completely etched away, leaving a metal sheet having micron-size holes therethrough.