Two 200 m²/g hydrophilic fumed silicas compared on specs, performance, supply chain, and total cost of ownership for industrial formulators.
Two 200 m²/g hydrophilic fumed silicas compared on specs, performance, supply chain, and total cost of ownership for industrial formulators.
Both SEMISIL 200 and AEROSIL 200 target a nominal BET surface area of 200 ±25 m²/g and a primary particle diameter of approximately 12 nm. These two parameters govern the silica’s ability to form hydrogen-bonded networks in liquid media. In practice, batch-to-batch BET on AEROSIL 200 typically lands at 190–220 m²/g; SEMISIL 200 operates within the same corridor at 185–215 m²/g. The overlap means rheological behavior in epoxies, polyester resins, and silicone sealants is functionally equivalent at equal loading levels. For a deeper look at how BET grades scale from 150 to 380 m²/g, see our BET comparison guide.
Thixotropy is the primary reason formulators add 200-grade fumed silica. Both grades deliver a thixotropic index (TI) of 4.0–6.0 when dispersed at 2–3 wt% in medium-viscosity epoxy systems (base viscosity ~500 mPa·s). Shear-thinning onset, recovery time, and anti-sag performance are comparable because aggregate morphology — branched-chain aggregates of 100–250 nm — is nearly identical between the two products. The key variable is dispersion quality: high-shear mixing above 10 m/s tip speed for ≥15 minutes is required regardless of brand. Under-dispersed silica yields lower TI and false comparisons.
AEROSIL 200 ships from Evonik plants in Germany (Rheinfelden) and the US (Mobile, AL), with typical lead times of 6–10 weeks for Asian buyers and 3–5 weeks within Europe and North America. SEMISIL 200 is manufactured in China with ex-works lead times of 2–4 weeks and FOB pricing that reflects lower energy and labor costs. For formulators in Southeast Asia, the Middle East, or Africa, SEMISIL offers a meaningful logistics advantage. Both suppliers provide 10 kg bags and 200 kg drums; SEMISIL also offers flexible 25 kg packaging as standard. See the full SEMISIL 200 product page for packaging and MOQ details.
On a per-kilogram FOB basis, SEMISIL 200 typically runs 30–40% below AEROSIL 200 pricing, depending on volume and destination. For a mid-size adhesive compounder using 5 tonnes/month, that gap translates to $15,000–$25,000 in annual raw-material savings at current market rates. Total cost of ownership should also factor in qualification testing (1–2 batches), potential reformulation of additive packages, and any shelf-life revalidation. Because the two grades are spec-equivalent, most drop-in trials require only a standard QC panel — viscosity curve, TI measurement, and accelerated aging — rather than full re-formulation.
The table below consolidates the key published specifications for both grades. Where ranges differ, the practical…
The table below consolidates the key published specifications for both grades. Where ranges differ, the practical impact on end-use performance is negligible for most coating, adhesive, and sealant applications.
| Property | SEMISIL 200 | AEROSIL 200 | Unit |
|---|---|---|---|
| BET Surface Area | 185–215 | 190–220 | m²/g |
| Primary Particle Size | ~12 | ~12 | nm |
| Tapped Density | ~50 | ~50 | g/L |
| pH (4% dispersion) | 3.7–4.5 | 3.7–4.7 | — |
| SiO₂ Content | ≥99.8 | ≥99.8 | % |
| Loss on Drying (2h, 105°C) | ≤1.5 | ≤1.5 | % |
| Loss on Ignition (2h, 1000°C) | ≤1.0 | ≤1.0 | % |
| Sieve Residue (45 µm) | ≤0.05 | ≤0.05 | % |
SEMISIL 200 matches AEROSIL 200 on every critical specification — BET, particle size, purity, and thixotropic index. For formulators seeking to reduce cost without re-formulating, it qualifies as a direct drop-in replacement with 30–40% savings and shorter lead times from Asian supply.
Yes, SEMISIL 200 is a drop-in replacement for AEROSIL 200 in most coating, adhesive, and sealant formulations. Both share the same BET range (200 ±25 m²/g), primary particle size (~12 nm), and purity (≥99.8% SiO₂). A standard QC validation — viscosity curve plus thixotropic index — is sufficient to confirm equivalence in your specific system.
Higher BET surface area increases the density of silanol groups available for hydrogen bonding, which strengthens the three-dimensional network that creates thixotropy. At 200 m²/g, both grades provide a thixotropic index of 4.0–6.0 at 2–3 wt% loading in epoxy systems. See our BET comparison guide for behavior across the 150–380 m²/g range.
SEMISIL 200 is typically 30–40% less expensive on a per-kilogram FOB basis compared to AEROSIL 200. The exact delta depends on order volume, destination, and current freight rates. For a compounder using 5 tonnes per month, annual savings range from $15,000 to $25,000.
SEMISIL 200 ships ex-works from China with lead times of 2–4 weeks, compared to 6–10 weeks for AEROSIL 200 shipments to Asian destinations. Standard packaging includes 10 kg bags, 25 kg bags, and 200 kg drums. Minimum order quantities depend on destination and logistics routing.
Use high-shear mixing at a tip speed above 10 m/s for at least 15 minutes to fully de-agglomerate the silica and maximize thixotropic index. Under-dispersion is the most common cause of poor performance and misleading grade-to-grade comparisons. This applies equally to SEMISIL 200 and AEROSIL 200.
Fumed silica builds thixotropy far more efficiently than precipitated silica because its branched-chain aggregate structure creates stronger hydrogen-bonded networks at lower loading. Precipitated silica is better suited to reinforcement and cost-driven filler applications. Our fumed vs precipitated comparison details the full trade-off.
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