nm-SiO2 powderused in electronic encapsulation, polymer of macromolecule, rubber, plastics, coating, paint, adhesive and so on nm-SiO2 powder SiO2%wt,dry ≥98.0%Particle sizenm ≤30Specific surface aream2/g 200Moisture110,2h,wt ≤5%Loss on Ignition900,2h,wt ≤2%Rocking density(g/cm3) ≤0.05PH(4% water dispersant) 4-6 nm-SiO2 powder