Particle size characterization of ultrafine tungsten powder

摘要: Abstract The aim of this research was to investigate the particle size measurement as-supplied and lab-milled ultrafine tungsten powders. powder derived from X-ray diffraction pure WO3 by hydrogen reduction process under “dry” conditions milled for 1, 2 4 h, respectively. Then powders were used perform laser method Fisher sub-sieve sizer (FSSS) BET through adsorption isotherms. Results show that mean values measured FSSS misleading because defects system or unsuitability theory. And calculated dBET formula 6/(S density ) smaller than SEM method, which resulted neglect effect surface roughness pore area on calculation. fractal dimension D external St pores obtained isotherms, modify calculation formula. modified d ( M =k (D/2)×6/(S ), where coefficient k a constant, it function area, value roughness. As in investigation, defined as SBET/St, so dBET(M) may be expressed 3D/( S t ). By formula, four study good agreement with sizes.