Fumed Oxide Dispersions for Ceramic Slurries, Investment Casting and Coatings
Ceramic processing depends on slurry behaviour: viscosity stability during storage, anti-settling in the vessel, and controlled flow during casting. Evonik's AERODISP® dispersions of fumed silica and fumed alumina are engineered for exactly these tasks.
Why Choose Evonik for Ceramics?
- Extended Slurry Shelf Life: In investment casting, AERODISP® fumed alumina binders extend slurry shelf life to more than two months, compared with less than two days for common TEOS- and colloidal-silica-based binders.
- Structure That Works at Low Dosage: AERODISP® dispersions are built from aggregated nano-sized primary particles with a branched, grape-cluster structure. This aggregate structure delivers results at relatively small addition levels compared with conventional colloidal systems.
- Ready to Use: Solid contents from 12 to 50 % by weight, particle sizes from 50 to 300 nm, and low viscosity — supplied as a stable dispersion, with no powder handling and no dust exposure.
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Solutions by Application
Ceramic Slurries & Dispersions
AERODISP® – Aqueous dispersions of fumed silica and fumed alumina for rheology control and anti-settling in ceramic slurries. AERODISP® W 925 is a fumed alumina dispersion with 24–26 % solids and an acidic pH; its positively charged particles and high surface area make it suitable for ceramic applications.
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Investment casting binders
- AERODISP® – Ready-to-use binder for investment casting by the lost wax method. It increases slurry viscosity and provides an anti-settling effect during storage, extending shelf life to more than two months against less than two days for common TEOS- and colloidal-silica-based binders. The fine alumina particles bind the coarser sand particles and form a permanent bond after firing of the mold. The result is more consistent slurry viscosity, higher quality consistency and less scrap in casting.
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Ceramic coatings
- AERODISP® W 7520 NF – Aqueous dispersion of hydrophilic fumed silica, pH 9.5–10.5, SiO₂ content 19–21 %, viscosity below 100 mPa·s. It helps avoid cracking in inorganic ceramic coatings and provides an excellent anti-settling effect. Recommended for food contact applications, including cook and bakeware.
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How the aggregate structure works AERODISP® dispersions differ from conventional colloidal systems in the structure of their particles. The dispersed material consists of nano-sized primary particles fused into branched aggregates resembling a cluster of grapes. Key factors are the size and number of primary particles, the degree of coalescence and the branching of the aggregate. This structure builds a network in the liquid phase that holds coarser particles in suspension — which is why comparatively small addition levels can deliver a strong anti-settling and rheological effect.
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The Evonik Advantage
- High Purity & Consistency: Engineered for demanding ceramic applications with tight control over particle size and composition.
- Global Expertise: Our technical teams collaborate with you to optimize formulations and scale production.
- Proven Track Record: Evonik has been manufacturing fumed silica dispersions since 1953.
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Ready to Shape the Future of Ceramics?
Discover how AERODISP® can support your process — from slurry stability and anti-settling to investment casting binders and crack-free ceramic coatings.
Contact us or explore our solutions.