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Fumed Silica
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Fumed Silica

ELVISCTM – FuSi

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Fumed silica (also called fumed silicon dioxide, SiO₂) is a high-purity, amorphous fumed silica powder valued for its exceptional thickening, thixotropic and anti-caking behaviour. Produced by flame…

CAS Number

112945-52-5

HS Code

28112200

INCI Name

Fumed Silica

Molecular Formula

SiO2

Home/Products/Fumed Silica

Fumed Silica

ELVISCTM – FuSi

Fumed silica (also called fumed silicon dioxide, SiO₂) is a high-purity, amorphous fumed silica powder valued for its exceptional thickening, thixotropic and anti-caking behaviour. Produced by flame hydrolysis, it delivers very high surface area at ≥99.8% purity and is used…

CAS Number

112945-52-5

INCI Name

Fumed Silica

HS Code

28112200

Molecular Formula

SiO2

Get Pricing for This Product

Need pricing? Request a quote for this product and we'll get back to you shortly.

Free Samples Available

Speed Up Your Sample Testing Process

We deliver domestic samples within 24 - 48 hours, helping you evaluate product without delays.

Fumed Silica
Bags
ElixirByElchemy

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Product Specification

AppearanceWhite, fluffy powder
OdorOdorless
Molecular Weight60.08 g/mol
Density / Specific Gravity2.2 g/cm³
ViscosityNot applicable (used as a thickening agent)
Refractive Indexn20/D 1.46
Ph (Aqueous Solution)3.7 - 4.5 (in 4% dispersion)
Assay / Purity≥ 99.8% SiO₂

Physical Properties

PropertySpecification
AppearanceWhite, fluffy powder
OdorOdorless
Molecular Weight60.08 g/mol
Density / Specific Gravity2.2 g/cm³
ViscosityNot applicable (used as a thickening agent)
Refractive Indexn20/D 1.46
Ph (Aqueous Solution)3.7 - 4.5 (in 4% dispersion)
Assay / Purity≥ 99.8% SiO₂

Chemical Properties

PropertySpecification
Ionic NatureNon-ionic, but surface silanol groups (Si-OH) can engage in hydrogen bonding. Standard fumed silica is acidic in nature.
IncompatibilitiesIncompatible with fluorine, oxygen difluoride, chlorine trifluoride, strong acids, and strong bases.
Hazardous Reactions / Decomposition ProductsThe material is stable and not normally reactive. Hazardous decomposition products are not expected under normal conditions of use. Thermal decomposition may generate oxides of carbon.

Thermal Properties

PropertySpecification
Melting Point1700 °C
Boiling Point2230 °C
Flash PointNot applicable
Decomposition Temperature> 400 °C
Thermal StabilityStable under recommended storage and handling conditions.

Processing Methods & Reference Formulations

A. High-Solids Anti-Corrosion Coating

A formulation designed for protective coatings with good sag resistance and pigment suspension.

Key IngredientsIndicative Dosage (% w/w)
Epoxy Resin50.0%
Polyamide Curing Agent25.0%
Titanium Dioxide15.0%
Talc7.5%
Fumed Silica1.5%
Xylene1.0%

B. General Purpose RTV Silicone Sealant

A one-component, moisture-curing sealant for construction and general industrial use.

Key IngredientsIndicative Dosage (% w/w)
Polydimethylsiloxane (PDMS) Polymer75.0%
Plasticizer (e.g., Dimethylpolysiloxane)12.0%
Fumed Silica7.0%
Crosslinker (e.g., Methyltriacetoxysilane)5.0%
Adhesion Promoter1.0%

Dosing Guidelines

A. Dosing by Application

ApplicationRecommended / Max Dosage
Paints & Coatings0.5% - 5.0%
Adhesives & Sealants2.0% - 8.0%
Resins (Epoxy, Polyester)0.5% - 5.0%
Powder Coatings0.5% - 1.5%
Rubber (Silicone)5.0% - 30.0%

About Fumed Silica

Fumed silica (also called fumed silicon dioxide, SiO₂) is a high-purity, amorphous fumed silica powder valued for its exceptional thickening, thixotropic and anti-caking behaviour. Produced by flame hydrolysis, it delivers very high surface area at ≥99.8% purity and is used across coatings, adhesives, sealants and elastomers (CASE), cosmetics, and food. Elchemy supplies both hydrophilic and hydrophobic grades in bulk, with documented specifications and fast US delivery.


Fumed Silica Grades: Hydrophilic & Hydrophobic

Fumed silica is offered in two families. Hydrophilic fumed silica (untreated) carries surface silanol groups and disperses in polar systems - ideal for water-based coatings, thickening and anti-settling. Hydrophobic fumed silica is surface-treated to repel water, giving better moisture resistance and flow in resins, powders and sealants. Grades equivalent to common aerosil and cabosil fumed silica types are available; a cabosil-style thickening agent grade is stocked for coatings and composites. Tell us your system and we will match the right grade - see the technical data sheet for full specifications.


Fumed Silica Supplier, Manufacturer & Distributor

Elchemy is a fumed silica supplier and distributor serving manufacturers across the United States and worldwide. As a chemical supplier working directly with producers, we provide consistent, batch-tested fumed silica powder with full documentation (CoA, TDS, SDS), regulatory support and reliable lead times. Whether you need a single grade for R\&D or a qualified fumed silica manufacturer partner for recurring production volumes, our team handles specification matching, sampling and supply continuity so procurement stays predictable.


Buy Fumed Silica in Bulk - Pricing & Quotes

Looking to buy fumed silica in bulk? Elchemy offers competitive bulk pricing across hydrophilic and hydrophobic grades, from trial quantities to drum and pallet volumes. Because fumed silica pricing moves with grade, surface treatment and order size, we quote per requirement rather than list a fixed rate. Request a bulk quote and receive pricing within 48 hours, or request a sample for evaluation before you commit. Wondering where to buy fumed silica with dependable US delivery - start with a quote and our team will confirm availability and shipping.

  • High Surface Area: Provides excellent thickening and thixotropic properties, enhancing product performance.
  • Function: Thickener, Thixotropic Agent, Anti-Caking Agent, Reinforcement, Matting Agent, Anti-Settling Agent, Flow Aid.
  • Versatile Applications: Used in coatings, adhesives, sealants, and cosmetics for various functional benefits.
  • Features: High surface area, low bulk density, high purity, and a three-dimensional chain-like particle structure. Technical grades can be hydrophilic (untreated) or hydrophobic (surface-treated).
  • Eco-Friendly Production: Produced with a focus on sustainability and minimal environmental impact.
  • Benefits: Provides highly effective viscosity control and thixotropy (shear-thinning). Prevents pigment and filler settling, improves sag resistance in coatings, enhances mechanical properties like tensile and tear strength in elastomers, and improves the flow and prevents clumping of powders.
  • Consistent Quality: Ensures reliable performance across different applications and industries.
  • Improved Stability: Enhances the stability and texture of formulations, preventing separation and settling.

About Fumed Silica

Fumed silica (also called fumed silicon dioxide, SiO₂) is a high-purity, amorphous fumed silica powder valued for its exceptional thickening, thixotropic and anti-caking behaviour. Produced by flame hydrolysis, it delivers very high surface area at ≥99.8% purity and is used across coatings, adhesives, sealants and elastomers (CASE), cosmetics, and food. Elchemy supplies both hydrophilic and hydrophobic grades in bulk, with documented specifications and fast US delivery.


Fumed Silica Grades: Hydrophilic & Hydrophobic

Fumed silica is offered in two families. Hydrophilic fumed silica (untreated) carries surface silanol groups and disperses in polar systems - ideal for water-based coatings, thickening and anti-settling. Hydrophobic fumed silica is surface-treated to repel water, giving better moisture resistance and flow in resins, powders and sealants. Grades equivalent to common aerosil and cabosil fumed silica types are available; a cabosil-style thickening agent grade is stocked for coatings and composites. Tell us your system and we will match the right grade - see the technical data sheet for full specifications.


Fumed Silica Supplier, Manufacturer & Distributor

Elchemy is a fumed silica supplier and distributor serving manufacturers across the United States and worldwide. As a chemical supplier working directly with producers, we provide consistent, batch-tested fumed silica powder with full documentation (CoA, TDS, SDS), regulatory support and reliable lead times. Whether you need a single grade for R\&D or a qualified fumed silica manufacturer partner for recurring production volumes, our team handles specification matching, sampling and supply continuity so procurement stays predictable.


Buy Fumed Silica in Bulk - Pricing & Quotes

Looking to buy fumed silica in bulk? Elchemy offers competitive bulk pricing across hydrophilic and hydrophobic grades, from trial quantities to drum and pallet volumes. Because fumed silica pricing moves with grade, surface treatment and order size, we quote per requirement rather than list a fixed rate. Request a bulk quote and receive pricing within 48 hours, or request a sample for evaluation before you commit. Wondering where to buy fumed silica with dependable US delivery - start with a quote and our team will confirm availability and shipping.

  • High Surface Area: Provides excellent thickening and thixotropic properties, enhancing product performance.
  • Function: Thickener, Thixotropic Agent, Anti-Caking Agent, Reinforcement, Matting Agent, Anti-Settling Agent, Flow Aid.
  • Versatile Applications: Used in coatings, adhesives, sealants, and cosmetics for various functional benefits.
  • Features: High surface area, low bulk density, high purity, and a three-dimensional chain-like particle structure. Technical grades can be hydrophilic (untreated) or hydrophobic (surface-treated).
  • Eco-Friendly Production: Produced with a focus on sustainability and minimal environmental impact.
  • Benefits: Provides highly effective viscosity control and thixotropy (shear-thinning). Prevents pigment and filler settling, improves sag resistance in coatings, enhances mechanical properties like tensile and tear strength in elastomers, and improves the flow and prevents clumping of powders.
  • Consistent Quality: Ensures reliable performance across different applications and industries.
  • Improved Stability: Enhances the stability and texture of formulations, preventing separation and settling.

Regulatory Compliance

RegionMax Allowed LevelNotesCertification Body
Australia-Not considered to pose an unreasonable risk to health. Ingredients must be listed on the Australian Inventory of Industrial Chemicals (AIIC).Importers/manufacturers must be registered with the Australian Industrial Chemicals Introduction Scheme (AICIS).
Canada-Not listed on the Cosmetic Ingredient Hotlist of prohibited or restricted substances. Listed on the Domestic Substances List (DSL).-
China-Listed on the Inventory of Existing Chemical Substances in China (IECSC).-
Japan-Not listed on the List of Ingredients Prohibited in Cosmetic Products. Ingredients must comply with the Standards for Cosmetics. Listed on the ENCS inventory.Marketing Authorization Holder (MAH) license required for import and sale.
Republic of Korea-General cosmetics do not require pre-market registration but must comply with regulations. Listed on the Korean ECL inventory.Importers must be registered as a "marketing authorization holder" (MAH).
United States2%Food: Listed as Generally Recognized as Safe (GRAS) for use as an anti-caking agent. Cosmetics: The Cosmetic Ingredient Review (CIR) Expert Panel concluded that amorphous silica is safe for use in cosmetics when formulated to be non-irritating.TSCA: The substance is listed on the TSCA inventory.
ASEAN-Not found on the lists of prohibited or restricted substances in the Annexes of the ASEAN Cosmetic Directive (ACD).Compliance with the ASEAN Cosmetic Directive.
European Union-Food: Approved as food additive E 551. Cosmetics: The Scientific Committee on Consumer Safety (SCCS) has not been able to draw a firm conclusion on the safety of nano-forms of silica due to data gaps. If considered a nanomaterial (insoluble with >50% of particles <100 nm), specific notification and safety assessment are required.REACH: The substance is registered under REACH.

FAQs - Fumed Silica

What is Fumed Silica used for?
Fumed Silica is used in a variety of applications including as a thickener, thixotropic agent, anti-caking agent, and reinforcement in coatings, adhesives, sealants, and cosmetics.
Is Fumed Silica safe?
Fumed Silica is generally considered safe when used as intended. However, inhalation of dust should be avoided, and appropriate safety measures should be taken during handling.
How is Fumed Silica produced?
Fumed Silica is produced by the flame hydrolysis of silicon tetrachloride, resulting in a high-purity, amorphous silica powder.
What is the difference between hydrophilic and hydrophobic fumed silica?
Hydrophilic fumed silica is untreated and disperses well in water-based and polar systems for thickening and anti-settling. Hydrophobic fumed silica is surface-treated to repel moisture, giving better water resistance and flow in resins, powders and sealants. Elchemy supplies both grades.
Is fumed silica the same as silica fume?
No. Fumed silica is a high-purity amorphous powder made by flame hydrolysis of silicon tetrachloride, used as a thickener and reinforcing agent. Silica fume is a byproduct of silicon-metal production used mainly as a concrete admixture. They are different materials - this page is for fumed (pyrogenic) silica.
Is fumed silica the same as Aerosil or Cabosil?
Aerosil and Cabosil are brand names for fumed silica. Elchemy stocks grades equivalent to common aerosil and cabosil types, including a cabosil-style thickening-agent grade for coatings and composites. Share your current grade and we will match it.
How is fumed silica made?
It is produced by flame hydrolysis of silicon tetrachloride at high temperature, which yields a very high-purity, amorphous silica powder with extremely high surface area.
Is fumed silica safe or toxic?
Fumed silica (amorphous) is generally recognised as safe when handled correctly and is approved as food additive E 551 / GRAS as an anti-caking agent. It is not the same as crystalline silica. As with any fine powder, avoid inhaling dust and use appropriate PPE; see the SDS for full guidance.
Is fumed silica hydrophobic?
It can be. Hydrophilic (untreated) grades are naturally water-attracting, while hydrophobic grades are surface-treated to repel water. Choose the grade based on whether your system is water-based or moisture-sensitive.
How much fumed silica should I use?
Typical dosage depends on the system: 0.5–5% in paints and resins, 2–8% in adhesives and sealants, 0.5–1.5% in powder coatings, and up to 30% in silicone rubber. Start low and adjust to reach the target viscosity or reinforcement.
Where can I buy fumed silica in bulk?
Elchemy supplies fumed silica in bulk across the US and internationally, from trial quantities to drums and pallets, in both hydrophilic and hydrophobic grades. Request a quote and our team confirms grade, availability and delivery.
How much does fumed silica cost?
Pricing depends on grade, surface treatment and order volume, so we quote per requirement rather than a fixed rate. Request a bulk quote for pricing within 48 hours, and a sample for evaluation before ordering.

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