Porous Pellets of Tungsten Nano Powder: Investigation of Surface Porosity of Machined Surfaces

The pressed dispenser cathodes are showing problem in machining due to their less strength because of low sintering temperature. In this paper, the synthesis of Nano tungsten powders and the fabrication of machinable porous Nano tungsten matrices were discussed. The Nano tungsten powders were synthesized by two different routes. One is by using Ammonium Meta Tungstate in sol gel technique and other is dissolving micron sized tungsten particles in Hydrogen Peroxide (H2O2). Using these synthesized Nano powders, the pellets were fabricated and the results were compared with the pellet made of commercially available tungsten powder (particle size 0.6–1 μ). The pressed porous tungsten buttons are sintered at high temperature and machining is carried out after copper infiltration. In this paper, surface morphology, hardness and machinability of porous tungsten Nano pellets were discussed.