Censil fumed silica for coatings — high-performance matting agent, anti-settling & rheology modifier for powder coatings, UV coatings, and industrial coatings. Alternative to Aerosil & Cab-O-Sil. Free sample.
## Fumed Silica for Coatings: Enhancing Performance and Aesthetics
Sensilchem's Fumed Silica for Coatings is an ultrafine, amorphous white powder renowned for its exceptional thixotropic and reinforcing properties. It is a vital additive for a wide range of coating systems, improving their rheological behavior, scratch resistance, and overall durability.
### Key Advantages:
* **Rheology Control:** Acts as an effective thickening and anti-settling agent, preventing pigment sedimentation and ensuring consistent film thickness.
* **Scratch Resistance:** Significantly improves the hardness and scratch resistance of coatings, enhancing their protective qualities.
* **Anti-Sagging Properties:** Prevents sagging and dripping in high-build coating applications, ensuring smooth and uniform surfaces.
* **Matting Effect:** Can be utilized to achieve desired matting effects in various finishes.
### Applications:
Our fumed silica is indispensable in:
* **Paints and Varnishes:** Enhances anti-settling, thixotropy, and scratch resistance.
* **Inks:** Improves print quality and prevents pigment settling.
* **Adhesives and Sealants:** Controls viscosity and improves bonding strength.
* **Gel Coats:** Provides sag resistance and reinforcement.
Elevate your coating formulations with Sensilchem's Fumed Silica, engineered for superior performance and aesthetic appeal.
Interested in Censil silica?
Request a free 200g sample and evaluate the performance yourself.
Request a Free Sample →Censil is a China-based fumed silica manufacturer specializing in gas-phase silica for coatings applications. Produced by Longyan Shenghe Chemical Co., Ltd. in Fujian, China, Censil fumed silica is manufactured through the flame hydrolysis of high-purity silicon tetrachloride (SiCl₄), delivering ultra-fine primary particles (12-20 nm) with exceptionally high BET surface areas ranging from 150 to 380 m²/g and SiO₂ purity ≥99.9%.
Censil fumed silica serves as a high-performance rheology modifier for coatings, providing anti-settling, anti-sagging, and thixotropic properties across a broad range of coating systems — including powder coatings, liquid industrial coatings, automotive finishes, wood coatings, and marine protective coatings. With four standardized grades (Censil 150, 200, 300, and 380), Censil offers a cost-effective alternative to Aerosil, Cab-O-Sil, and HDK fumed silica for coating formulators worldwide.
Censil fumed silica is widely used as a rheology modifier for powder coatings, where precise flow behavior during extrusion, grinding, and application is critical. The ultra-fine fumed silica particles (12-20 nm primary particle size) form a three-dimensional hydrogen-bonded network through surface silanol groups, creating a thixotropic structure that prevents pigment and filler settling in the powder blend while enabling smooth flow under shear during application.
| Function | Mechanism | Recommended Grade | Typical Dosage |
|---|---|---|---|
| Anti-sagging | Thixotropic network prevents film running on vertical surfaces during cure | Censil 200 / 300 | 0.5-2.0% |
| Anti-settling | Suspending pigment and metallic flakes during storage and transport | Censil 150 / 200 | 0.3-1.5% |
| Flow control | Shear-thinning behavior for even film build without orange peel | Censil 200 | 0.5-1.5% |
| Reinforcement | Improving mechanical strength and scratch resistance of cured film | Censil 300 / 380 | 1.0-3.0% |
| Corrosion resistance | Densifying the coating matrix to block moisture penetration | Censil 200 / 300 | 1.0-2.0% |
As a fumed silica for powder coatings, Censil grades are compatible with epoxy, polyester, epoxy-polyester hybrid, and polyurethane powder coating systems. The hydrophilic surface chemistry ensures excellent compatibility with most resin systems, while the high purity (SiO₂ ≥99.9%) prevents unwanted reactions during the curing process.
Censil fumed silica is an essential rheology modifier for liquid coatings, providing thixotropic behavior that enables coatings to remain stable during storage yet flow easily during application. Whether in solvent-borne, water-borne, or high-solids formulations, Censil gas-phase silica delivers consistent rheological performance through its hydrogen-bonding silanol network.
| Coating Type | Recommended Grade | Primary Function | Addition Level | Compatibility |
|---|---|---|---|---|
| Industrial Enamels | Censil 200 | Anti-sagging, anti-settling | 0.5-2.0% | Solvent-borne, water-borne |
| Automotive Clear Coats | Censil 300 | High transparency rheology, sag control | 1.0-2.0% | 2K PU, solvent-borne |
| Marine Coatings | Censil 300 / 380 | High-build anti-sag, anti-corrosion | 1.5-3.0% | Epoxy, polyurethane |
| Wood Coatings / Furniture Lacquers | Censil 150 / 200 | Matting, flow control, sandability | 0.5-1.5% | NC, PU, UV-cure |
| Anti-Corrosion Primers | Censil 200 / 300 | Zinc dust suspension, barrier enhancement | 1.0-2.5% | Epoxy, solvent-borne |
| UV-Curable Coatings | Censil 150 | Rheology without inhibiting cure | 0.3-1.0% | UV-acrylate, radiation-curing |
| Coil Coatings | Censil 200 / 380 | Film build control, pigment suspension | 0.5-2.0% | Polyester, PVDF, solvent-borne |
As a thixotropic agent for liquid coatings, Censil fumed silica enables formulators to achieve the ideal balance between storage stability and application performance. The low loss on drying (<1.5%) ensures minimal moisture introduction into moisture-sensitive systems such as 2K polyurethane coatings.
Beyond conventional industrial and automotive coatings, Censil fumed silica is used in specialty coating applications where extreme performance requirements demand the highest purity and most precise rheological control. With SiO₂ purity ≥99.9% and carefully controlled surface chemistry, Censil gas-phase silica meets the stringent demands of electronics, optical, and high-performance protective coatings.
| Application | Recommended Grade | Function | Key Benefit |
|---|---|---|---|
| Conformal Coatings (Electronics) | Censil 200 | Thixotropy, anti-settling | Precise flow on PCB, no pooling |
| Intumescent Fire-Retardant Coatings | Censil 300 / 380 | Structural reinforcement, rheology | Stabilizes intumescent char layer |
| Anti-Graffiti Coatings | Censil 200 | Surface texturing, flow modification | Low surface energy, easy cleaning |
| Coating Adhesives (PSA, Structural) | Censil 150 / 200 | Reinforcement, viscosity control | Improved cohesive strength, non-sag |
| Thermal Insulation Coatings | Censil 380 | Low thermal conductivity filler | Enhanced insulation performance |
| Optical / Anti-Reflective Coatings | Censil 150 | Refractive index adjustment | High purity ensures optical clarity |
Censil fumed silica's high purity (SiO₂ ≥99.9%) and low ionic impurity content make it the preferred choice for electronics and optical coating applications where contamination must be minimized. The consistent particle size (12-20 nm primary particles) ensures uniform dispersion and predictable performance across batches.
Censil offers four fumed silica grades optimized for coatings, covering the full range of BET surface areas from 150 to 380 m²/g. Each grade is manufactured through flame hydrolysis of SiCl₄ (gas-phase process), ensuring ultra-high purity with SiO₂ ≥99.9% and consistent batch-to-batch quality. Selection is primarily based on the required surface area and the degree of rheological effect needed.
| Property | Censil 150 | Censil 200 | Censil 300 | Censil 380 |
|---|---|---|---|---|
| Appearance | White powder | White powder | White powder | White powder |
| SiO₂ (dry basis) | ≥99.9% | ≥99.9% | ≥99.9% | ≥99.9% |
| BET Surface Area (m²/g) | 150 ± 15 | 200 ± 25 | 300 ± 25 | 380 ± 30 |
| Primary Particle Size (nm) | ~20 | ~14 | ~7 | ~7 |
| Average Particle Size (µm) | 14-20 | 14-20 | 14-20 | 14-20 |
| Loss on Drying (105°C, 2h) | 0.5-1.0% | 0.5-1.0% | ≤1.5% | ≤1.5% |
| Loss on Ignition (1000°C, 2h) | 1.0-2.0% | 1.0-2.0% | ≤2.0% | ≤2.5% |
| pH (5% suspension) | 3.5-4.5 | 3.5-4.5 | 3.5-4.5 | 3.5-5.5 |
| DBP Absorption (ml/100g) | — | — | — | ≥180 |
| Bulk Density (g/L) | 40-50 | 40-50 | — | — |
| Whiteness | 98 | 98 | 98 | 98 |
| Surface Chemistry | Hydrophilic (silanol) | Hydrophilic (silanol) | Hydrophilic (silanol) | Hydrophilic (silanol) |
| Primary Coating Applications | UV coatings, mild rheology, optical coatings | General-purpose powder & liquid coatings | High-thixotropy automotive & marine | Maximum anti-settling, specialty coatings |
Coating formulators evaluating fumed silica for coatings often compare Censil against leading international brands including Evonik AEROSIL®, Cabot CAB-O-SIL®, and Wacker HDK. Below is a specification-level comparison demonstrating how Censil fumed silica matches these established brands while offering significant cost advantages as a China fumed silica manufacturer.
| Property | Censil 200 | AEROSIL® 200 | CAB-O-SIL® M-5 | HDK® H2000 |
|---|---|---|---|---|
| SiO₂ Content | ≥99.9% | ≥99.8% | ≥99.8% | ≥99.8% |
| BET Surface Area | 200 ± 25 m²/g | 175-225 m²/g | 200 ± 25 m²/g | 200 ± 30 m²/g |
| Loss on Drying | 0.5-1.0% | <1.5% | <1.5% | ≤1.5% |
| pH (5% suspension) | 3.5-4.5 | 3.7-4.5 | 3.8-4.3 | 3.5-4.5 |
| Primary Function | Rheology modifier | Rheology modifier | Rheology modifier | Rheology modifier |
| Surface Chemistry | Hydrophilic | Hydrophilic | Hydrophilic | Hydrophilic |
| Cost Index | 100 | 180-220 | 170-200 | 160-190 |
| Lead Time (FOB China) | 2-3 weeks | 6-10 weeks | 6-8 weeks | 4-8 weeks |
| Property | AEROSIL® R 805 | AEROSIL® R 812 | CAB-O-SIL® TS-530 | CAB-O-Sil® TS-720 |
|---|---|---|---|---|
| BET (m²/g) | 125-175 | 230-290 | ~230 | ~120 |
| Treatment Agent | Octyl silane | HMDS | HMDS | PDMS |
| Carbon Content | 4.5-6.5% | 2.0-3.0% | — | — |
| Recommended Use | Automotive clear coats, epoxy | 2K PU, powder coatings | Anti-corrosion coatings | Grease, highly polar systems |
Key Finding: Censil fumed silica matches the specifications of leading international brands including AEROSIL® 200, CAB-O-SIL® M-5, and HDK® H2000 while offering 40-55% cost savings. For coating formulators seeking an Aerosil alternative, Cab-O-Sil alternative, or HDK alternative for coatings, Censil delivers equivalent rheological performance with factory-direct China pricing and shorter lead times.
A common question from coating formulators is whether to use fumed silica or precipitated silica. Both are synthetic amorphous silicon dioxide, but they differ fundamentally in production method, particle morphology, and performance characteristics in coatings.
| Parameter | Fumed Silica (Gas-Phase) | Precipitated Silica |
|---|---|---|
| Production Method | Flame hydrolysis of SiCl₄ at ~1800°C | Chemical precipitation from Na₂SiO₃ + H₂SO₄ |
| Primary Particle Size | 5-50 nm (nano-scale) | 1-100 µm (micro-scale) |
| BET Surface Area | 150-400 m²/g | 50-350 m²/g |
| Bulk Density | 30-60 g/L (very low) | 120-300 g/L (moderate) |
| Morphology | Chain-like aggregates, branching | Irregular / spherical particles |
| Primary Function in Coatings | Rheology modifier, anti-sagging, anti-settling | Matting agent, flatting agent, extender |
| Effect on Gloss | Low addition = maintains gloss; High = matting | Reduces gloss (primary matting function) |
| Effect on Viscosity | Strong thickening even at low addition (0.5-3%) | Moderate viscosity increase at higher loading |
| Dispersibility | Requires high-shear mixing | Easier to disperse |
| SiO₂ Purity | ≥99.9% | ≥97-99.9% |
Summary: Use fumed silica for coatings when you need rheology control, anti-settling, anti-sagging, or thixotropic behavior at low addition levels. Use precipitated silica when you need matting/flatting, surface texturing, or cost-effective filler extension. Many coating formulations use both — fumed silica for rheological stability and precipitated silica for surface finish control.
| Property | Specification | Test Method |
|---|---|---|
| SiO₂ Content (dry basis) | ≥99.9% | GB/T 31586 |
| Production Method | Flame hydrolysis (gas-phase) | — |
| BET Surface Area | 150-380 m²/g (grade dependent) | GB/T 31586 |
| Loss on Drying (105°C, 2h) | 0.5-1.5% (grade dependent) | GB/T 31586 |
| Loss on Ignition (1000°C, 2h) | 1.0-2.5% (grade dependent) | GB/T 31586 |
| pH Value (5% suspension) | 3.5-5.5 | GB/T 31586 |
| CAS Number | 7631-86-9 / 112926-00-8 | — |
| Surface Chemistry | Hydrophilic (silanol groups) | — |
Fumed silica (gas-phase silica) is used in coatings as a rheology modifier, anti-settling agent, anti-sagging agent, and thixotropic agent. It forms a hydrogen-bonded network through surface silanol groups that prevents pigment settling during storage, controls sag on vertical surfaces during application, and provides shear-thinning behavior for easy brush or spray application. Censil fumed silica grades 150, 200, 300, and 380 are specifically designed for powder coatings, liquid industrial coatings, automotive coatings, and specialty formulations. Typical addition levels range from 0.3-3.0% depending on the coating system and desired effect.
Yes. Censil 150 and Censil 200 fumed silica are designed as cost-effective alternatives to Aerosil R805 for coatings. With matching BET surface area (150±15 and 200±25 m²/g), SiO₂ ≥99.9% purity, and equivalent rheological performance, Censil fumed silica delivers comparable anti-settling, anti-sagging, and thixotropic properties. For hydrophobic coating applications where Aerosil R805 (octyl-treated, BET 125-175 m²/g) is specified, Censil hydrophilic grades offer the rheological performance; customers requiring hydrophobic surface treatment should Contact Censil for customized solutions. As a China fumed silica manufacturer with factory-direct pricing, Censil offers 40-55% cost savings over imported brands.
Fumed silica (gas-phase silica) and precipitated silica differ in production method and performance. Fumed silica is produced by flame hydrolysis of SiCl₄, yielding ultra-fine primary particles (5-50 nm) with very high surface area (150-400 m²/g) — ideal for rheology control, anti-settling, and thixotropy in coatings. Precipitated silica is made by chemical precipitation from sodium silicate, with larger particles (1-100 µm) and moderate surface area (50-350 m²/g) — better suited as a matting agent and flatting agent for surface texture. Both are used in coatings, but fumed silica excels at rheological modification while precipitated silica excels at gloss reduction. Many coating formulations use both types for complementary performance.
Fumed silica can function as a matting agent by creating micro-roughness on the coating surface at the nano-scale. For effective matting with fumed silica, use high-surface-area grades like Censil 300 (BET 300±25 m²/g) or Censil 380 (BET 380±30 m²/g) at 1-3% addition level. Disperse the fumed silica into the coating using a high-speed dissolver or bead mill, ensuring complete breakdown of agglomerates to avoid haze. The degree of matting depends on the addition level, particle size, and film thickness. The advantage of using fumed silica as a matting agent over precipitated silica is that fumed silica simultaneously provides rheology control and anti-settling while achieving the desired matting effect.
For powder coatings, Censil 200 (BET 200±25 m²/g) is the standard recommendation as a rheology modifier and anti-settling agent. It provides excellent flow control during extrusion, prevents pigment settling in the powder blend, and ensures uniform film build. For high-performance powder coatings requiring stronger thixotropy, Censil 300 (BET 300±25 m²/g) delivers superior anti-sag properties at higher film builds. The recommended addition level is 0.5-2.0% calculated on total formulation weight. Censil fumed silica is compatible with epoxy, polyester, hybrid, and polyurethane powder coating chemistries.
Yes. Censil fumed silica is manufactured by Longyan Shenghe Chemical Co., Ltd. in Fujian, China, with over 20 years of silica production experience. Censil produces both fumed silica and precipitated silica, offering a complete silica solutions portfolio for coatings, feed, rubber, and industrial applications. The company holds ISO 9001 certification, and its fumed silica products consistently achieve SiO₂ ≥99.9% purity with tight BET surface area tolerances. Censil serves coating manufacturers across Asia, Europe, and the Americas as a factory-direct fumed silica supplier, offering competitive pricing with 2-3 week lead times — significantly faster than the 6-10 week lead times from European manufacturers.