... Average diameter (nm) Purity (%) Surface area (m 2 / g) Bulk density (g / cm 3) Crystal form Nanoscale Black 50 > 99 ... elements , and high antioxidant capacity, low sintering temperature, black powder, average particle size 30-80nm, purity 99.99%. High-performance ... wave absorption. Iron, cobalt, zinc oxide powder and carbon-coated metal powder can be used as high-performance millimeter-wave ...