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AEROSIL® 300 is a hydrophilic fumed silica with a specific surface area of 300 m²/g.

INCI Name: Silica

Chemical Name: Pyrogenic Silica, Silica gel, pptd., cryst.-free

Functions: Anti-Caking Agent, Carrier, Filler, Heat Stabilizer, Leveling Agent, Reinforcement, Rheology Modifier, Stabilizer, Thickener, Thixotrope, Viscosity Modifier

Chemical Family: Silica, Silicates

Knowde Enhanced TDS

Identification & Functionality

Chemical Family
CASE Ingredients Functions
Composite Materials Functions
Cosmetic Ingredients Functions
Fluids & Lubricants Functions
Industrial Additives Functions

Features & Benefits

Benefit Claims
Product Features
  • Optimum adjustment of rheology during processing
  • Reinforcement of silicone elastomers
  • Thickening of non-polar liquids
  • Free-flow of industrial powders
  • High chemical purity
  • Excellent insulation properties, even at high and low temperatures

Applications & Uses

Fluids & Lubricants Type
AP/Deo Applications
Composites End Use
Fluids & Lubricants End Use
Ink & Toner Type
Oral Care Applications
Cable Gel Applications

Use of AEROSIL® fumed silica for cable gels gives excellent performance when it comes to shear-thinning, providing quick recovery and the gel does not require heat to be applied. AEROSIL® fumed silica improves properties of oil-based filling compounds for wire and cables to protect fibers (e. g. optical fibers) as it:

  • Supports to isolate sensitive optical fi bers from external forces
  • Protects the fi bers from moisture
  • Provides thickening to help the gel to stay where it is placed
  • Helps to form a seal to keep out contaminants like dust, dirt and water
  • Is non-conductive / does not negatively infl uence di-electrical properties
Lubricating Grease Applications

The use of AEROSIL® fumed silica is recommended for lubricating greases used in industrial applications, automotive, electrical as well as food grade.


  • High thixotropic effect
  • High temperature stability
  • Dielectric properties


  • High thixotropic effect
  • High temperature stability
  • Wear resistance
  • Extreme pressure resistance


  • High thixotropic effect
  • High temperature stability
  • Wear resistance
  • Reduced friction

Food - Hydrophilic AEROSIL® are generally recognized as safe (GRAS; direct food contact)

  • High thixotropic effect
  • High temperature stability
  • Wear resistance
AEROSIL® Fumed Silica in Lubricating Greases

AEROSIL® fumed silica helps to build a stable matrix to increase viscosity and suppress oil separation in lubricating greases. It can be used in the following systems:

  • In non-soap greases, used in high-temperature applications up to 230° C as well as for extreme-pressure and multipurpose greases.
  • In soap greases, thickened by fatty acid soaps of lithium, calcium, sodium or aluminum, AEROSIL® fumed silica can be used to further improve the performance of the lubricating grease.
  • Hydrophilic fumed silica provides optimized thickening effects in non-polar oils.
  • Hydrophobic fumed silica provides viscosity control and increased water repellency in semi-polar to polar oils.
  • The surface area of the silica and the volume fraction of the silica in the fi nal mass play a role in the long term storage and heat stability.


Physical Form
Physico-Chemical Properties
ValueUnitsTest Method / Conditions
Tamped Density*approx. 50g/l-
Specific Surface Area (BET)270 - 330m²/g-
SiO₂ Content (based on ignited material)min. 99.8%-
pH Value (in 4% dispersion)3.7 - 4.5--
Loss on Drying* (at 105 °C, 2 hours)max. 1.5%-

Regulatory & Compliance

Technical Details & Test Data

AEROSIL® Fumed Silica
  • AEROSIL® fumed silica is a highly dispersed, amorphous, very pure silica manufactured by high-temperature hydrolysis of silicon tetrachloride in an oxyhydrogen gas flame. The primary particles formed in the AEROSIL® process are virtually spherical and free of pores.
  • During the formation of the primary particles, aggregates are formed which further accumulate into agglomerates. Under shear, these agglomerates can be returned back into smaller aggregates.
  • Siloxane and silanol groups are found on the surface of the AEROSIL® particles. This latter type of functional group in particular is responsible for the hydrophilic behavior of untreated AEROSIL®. Figure shows the surface groups of hydrophilic AEROSIL® grades.

AEROSIL® 300 - Aerosil® Fumed Silica

Surface groups of hydrophilic AEROSIL® grades.

The hydrophobic nature of after treated AEROSIL® grades compared with AEROSIL® 300 can be illustrated by means of moisture adsorption in increasingly humid conditions. Figure below shows the corresponding isotherms.

AEROSIL® 300 - Aerosil® Fumed Silica - 1

Adsorption isotherms of various AEROSIL® grades at room temperature (small samples).

Packaging & Availability

Country Availability
Packaging Type
Regional Availability
  • North America
Packaging Information

AEROSIL® 300 is supplied in multiple layer 10 kg bags.

Storage & Handling

Shelf Life
2 years
Storage Conditions

Recommend to store the product in closed containers under dry conditions and to protect the material from volatile substances. AEROSIL® 300 should be used within 2 years after production.