Tungsten Ionizers with Controlled Porosity for Cesium-Ion Engines
Porous tungsten of a predictable high pore density has been developed for use as a high-efficiency ionizer in cesium-ion engines. Fine spherical tungsten powder was separated into six narrow size fractions ranging from 2.4 to 6.9 p in diameter. These powders were warm-pressed, at 400°C and 75,000 psi, to 74% of theoretical density. At a sintered density of 80% of theoretical, pore counts showed surface pore densities of 8 × 106 to 1.4 × 106 pores/cm2, depending upon original particle size. Curves are shown for pressed density versus sintered density for several particle sizes.
KeywordsSintered Density Powder Size Pore Density Tungsten Powder Tungsten Ionizer
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