Highly pure >99% SPHERICAL COPPER POWDER MADE USING INERT GAS ATOMIZATION. Mesh 400 Spherical Copper.HTS Code: 7406.10.0000 NMFC: 30743 CAS: 7440-50-8 Additional Description Used in Electronics, Injection Molding, Thermal Management, EDM Electrodes, Thermal Spray and other uses where fine spherical powder is needed. Microtrac % passing ……. Micron D10 14.5 D50 20 D90 25.87 90% of the particles are 25.87 micron or smaller Apparent Density: about 4 g/ccNote: Pure copper powders do not show continuity or conductivity by a multimeter. I think there are two reasons for that. One is the low voltage used for the test. The other is lots of air and weak contacts between the particles. They will show conductivity with higher voltage, when they are compacted and when they are mixed with some oil or resin to form a paste.