Buy Fumed Silica Silicon Dioxide
Fumed Silica (Silicon Dioxide) – Technical Overview
Fumed silica is a synthetic amorphous silicon dioxide produced by flame hydrolysis of silicon tetrachloride. The process yields primary particles in the nanometer range that agglomerate into loose, high‑surface‑area aggregates.
Key Properties
The material is characterized by a high specific surface area, low bulk density, and controllable surface chemistry. Typical ranges for commercially available grades are shown below.
| Property | Typical Range | Test Method |
|---|---|---|
| BET Surface Area | 50 – 400 m²/g | ASTM D3037 |
| Primary Particle Size | 5 – 50 nm | TEM / ISO 9276‑2 |
| Bulk Density (tapped) | 40 – 150 kg/m³ | ASTM D1895 |
| Loss on Ignition (2 h @ 1000 °C) | ≤ 2.0 % | ASTM D1203 |
| pH (5 % dispersion) | 3.5 – 5.5 | ISO 787‑9 |
Typical Applications
Fumed silica functions as a rheology modifier, anti‑settling agent, and reinforcing filler. Its utility stems from the ability to form a three‑dimensional network in liquids and to interact with polymer matrices.
- Silicone sealants and adhesives – prevents sagging and improves extrusion stability.
- Paints and coatings – provides thixotropic behavior, reduces pigment settling, and enhances sag resistance.
- Unsaturated polyester resins – improves viscosity control and reduces exotherm during cure.
- Pharmaceutical powders – acts as a glidant and anti‑caking agent for tablet formulation.
- Li‑ion battery electrolytes – increases viscosity to suppress dendrite growth and improve safety.
Available Grades
Grades differ primarily in surface area, surface treatment (hydrophilic vs. hydrophobic), and agglomeration structure. Selection is driven by the target medium’s polarity and the desired rheological profile.
| Grade Designation | Surface Area (m²/g) | Surface Treatment | Typical Use |
|---|---|---|---|
| Hydrophilic, low surface area | 50 – 100 | None (native silanol) | Polar systems, silicone rubber reinforcement |
| Hydrophilic, high surface area | 200 – 380 | None | High‑viscosity thixotropes, coating additives |
| Hydrophobic (silylated) | 100 – 300 | Trimethylsilyl or similar groups | Non‑polar resins, epoxy systems, battery electrolytes |
Quality Assurance
Each lot undergoes systematic testing to verify surface area, loss on ignition, pH, and moisture content. Results are reported against internal specifications that align with ASTM and ISO standards. Traceability is maintained from raw material receipt through final packaging.
Packaging & Storage
Product is supplied in multi‑wall paper bags with polyethylene inner liners, or in bulk flexible intermediate bulk containers (FIBCs) for larger volumes. Packaging options include 20 kg bags, 200 kg drums, and 1000 kg FIBCs. Store in a dry environment, preferably below 30 °C and relative humidity under 60 % to prevent moisture uptake.
For technical datasheets, sample requests, or to discuss specific grade selection, please use the inquiry form below.
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