Gaseous silica is a type of primary nano silica particle with high sphericity, high purity, and narrow particle size distribution, which is formed by a precise ratio of hydrogen and oxygen gas and chlorosilane. It undergoes gas-phase oxidation and hydrolysis reaction in a high-temperature hydrogen oxygen flame at 1100-1800 ℃. The ultrafine amorphous silica produced is known as "industrial monosodium glutamate" due to its wide range of applications.

Structure of fumed silica

Gas phase SiO2 is an atomic crystal that forms a three-dimensional network through Si-O bonds. In this crystal, each Si atom adopts sp3 hybridization to bind with four oxygen atoms through four covalent bonds, and many tetrahedra are connected as a whole through oxygen atoms at the vertices, that is, each oxygen atom is shared by two tetrahedra. Therefore, overall, the simplest formula for silicon dioxide is SiO2, but it does not represent a single molecule.

Silicon dioxide does not exist alone as native particles.

Structure of fumed silica

Organic halogenated silane is hydrolyzed and condensed at high temperature to obtain primary particles with a particle size of 7-350 nanometers. As the particles move away from the flame and the temperature decreases, they collide, adhere, and fuse with each other to form aggregates. Silica aggregates are composed of numerous particles fused together and have irregular shapes, mainly in the form of branched chains. And the aggregates are attracted by hydrogen bonds and van der Waals forces to form silica agglomerates. Agglomerates are unstable and easily separate under stress, and then tend to agglomerate again after the stress is eliminated, while aggregates are stable and generally believed not to be easily destroyed. High temperature gas-phase reaction belongs to molecular level uniform synthesis, without liquid phase interference or crystal defects. The generated silica primary particles have high sphericity, uniform particle size, and clean surface, building an excellent microstructure foundation.

Hydrophilic HQ gas-phase silica powder product series

Characteristics of gas-phase silica