What is fumed silica and what is it used for?
Fumed silica (pyrogenic silica, CAS 112945-52-5) is a synthetic amorphous silica that builds viscosity and controls flow at low loadings. It is used as a thickening and anti-settling rheology agent in liquids, resins and coatings, an anticaking free-flow agent in powders and foods, a pharmaceutical flow aid, and a viscosity and opacifying ingredient in cosmetics.
SILICA- ▸ Rheology control: thickening and anti-settling agent for liquids, resins and coatings
- ▸ Anti-caking: free-flow agent for powders and food products
- ▸ Pharmaceutical excipient: flow aid and excipient in drug and vitamin preparations
- ▸ Cosmetics: viscosity-controlling, opacifying and absorbent ingredient
- ▸ Technical Data Sheet (TDS) PDF · TDS
Values shown are typical for the current commercial grade. A lot-specific Certificate of Analysis accompanies every shipment; the grade-specific SDS is available on request.
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
Request SDS →Fumed silica (synthetic amorphous silicon dioxide, CAS 112945-52-5) is a high-surface-area pyrogenic silica. It is used as a thickening and anti-settling agent, as an anti-caking agent in powders and foods, as a pharmaceutical excipient, and as a viscosity-controlling and bulking ingredient in cosmetics.
Frequently Asked Questions
What is fumed silica used for?
Fumed silica (synthetic amorphous silicon dioxide, CAS 112945-52-5) is used as a thickening and anti-settling rheology agent for liquids, resins, and coatings, as a free-flow/anti-caking agent in powders and foods, as a pharmaceutical flow-aid excipient, and as a viscosity-controlling and absorbent ingredient in cosmetics.
What is the common name for fumed silica?
It is also called pyrogenic silica, and is widely known by trade names such as Aerosil and Cab-O-Sil. Chemically it is high-surface-area amorphous silicon dioxide (SiO2).
What is the difference between silica and fumed silica?
Fumed silica is a specific pyrogenic (flame-produced) form of silicon dioxide with very high surface area and a fine, fluffy structure, distinct from crystalline silica (such as quartz) or precipitated/silica gel forms. Its structure is what gives it thickening and anti-settling performance.
Is hydrophilic or hydrophobic fumed silica available?
Both surface treatments are common: untreated (hydrophilic) and surface-modified (hydrophobic) grades, selected by the carrier system. Specify the required grade and surface area on your RFQ.
What is the cost of bulk fumed silica and the HS code?
Pricing depends on grade, surface area, and packaging; request a bulk quote with your volume and delivery point. Fumed silica is classified under HS 2811.22, and an SDS and Certificate of Analysis accompany each shipment.