Fumed

Fumed is a term that can refer to various processes and materials, often involving the exposure to fumes or vapors. The term is commonly used in the context of fumed silica, a type of silica that is produced by the flame hydrolysis of silicon tetrachloride or from quartz sand vaporized in a 3000 °C electric arc. Fumed materials are characterized by their high surface area and unique properties, making them valuable in a variety of industrial applications.

Fumed Silica

Fumed silica is a white, fluffy powder consisting of high-purity silicon dioxide. It is produced by the flame hydrolysis of silicon tetrachloride or from quartz sand vaporized in a 3000 °C electric arc. The primary particles of fumed silica are extremely small, typically in the range of 5-50 nanometers, and they form branched, chain-like aggregates.

Properties

Fumed silica has several unique properties:

• High surface area
• Low bulk density
• High purity
• Thixotropic behavior

These properties make fumed silica useful in a variety of applications, including as a thickening agent, anti-caking agent, and in the production of silicone rubber.

Applications

Fumed silica is used in numerous industries:

• Pharmaceutical industry: as a glidant to improve the flow properties of powders.
• Cosmetics: as a thickening agent in creams and lotions.
• Paints and coatings: to control viscosity and improve stability.
• Adhesives and sealants: to enhance strength and durability.
• Food industry: as an anti-caking agent in powdered foods.

Fumed Metal Oxides

In addition to silica, other metal oxides can also be fumed, such as fumed alumina and fumed titania. These materials are produced through similar processes and have applications in various high-performance materials and coatings.

See Also

• Silicon dioxide
• Silicone rubber
• Pharmaceutical industry
• Cosmetics
• Paints and coatings
• Adhesives and sealants
• Food industry