Automotive Uses of Exfoliated Vermiculite
Friction Linings, Gaskets, and Fluid Sealing
Dicalite Managment Group is pleased to offer educated materials on the industrial uses of Vermiculite. The content on this page originates in Leon Bablouzian’s research paper Vermiculite Dispersions: A Unique Material for Fluid Sealing Applications.
Since the early 1900’s scientists and engineers have sought a unique combination of properties such as reinforcing stability and thermal stability for commercial gasket production. Today, properties derived from exfoliated vermiculite continue to meet the demands of thermal stability, reinforcing properties and the lubricating nature of gasket fields.
Fine Particulate Sized Vermiculite (FPSV)
Fine Particulate Sized Vermiculite (FPSV) and other finer grades of exfoliated vermiculite are used in friction linings for the automotive market. FPSV processed vermiculite is produced by thermal exfoliation in specially designed furnaces at ~1500°F where it expands up to 11 times in volume. The expanded vermiculite is then purified to remove contaminants and further processed to consistently meet particle size and bulk density requirements. FPSV processed vermiculite is used as a functional filler in wet lay gaskets used in automotive, as well as friction materials.
Vermiculite is used for this application because of its:
- Thermal resistance
- Surface characteristics
- Easy of addition to other raw materials
- Acoustic absorption
Both organic and inorganic high-performance materials such as polyimide, aramid, graphite, ceramic, and others have been developed for automotive applications. While each of these materials has merit in commercial automotive, friction lining and gasket applications, no single material has been found to be adequate, and it is common practice to use a multiplicity of substances to develop such products. While vermiculite has a similar structure to exfoliated graphite, it does not oxidize and is therefore very appropriate for automotive applications, including:
- Brake linings
- Clutch discs
- Rubber seals
- Automotive paints and lacquers
MicroLite® Vermiculite Dispersions has been shown to upgrade the heat and fire resistance, increase the abrasion resistance, and enhance the fluid sealing characteristics of many conventional substrates used in fluid sealing applications. Vermiculite dispersions take advantage of vermiculites layer mineral and charge characteristics to produce an inorganic, anisotropic, platy morphology that is particularly suitable in fluid sealing.
Because of the inherent high-temperature stability and oxidation resistance of vermiculite, the gaskets are intrinsically improved over graphite materials. No additional treatments or engineering considerations are needed to mask the oxidation potential. This makes for a user-friendly material that decreases post-manufacture handling.
Major benefits include extreme high-temperature stability, good torque retention, and superior oxidation resistance. It is thought the gaskets will have applicability in a wide range of stringent fluid sealing applications.