Seats
Carbon
Graphite has good corrosion resistance, high thermal conductivity and low friction, good self-lubrication and lower expansion. It can be used to make seal faces, bearings and so forth. It is ideal to use it as a frictional mating ring.
Ceramic
Ceramic seal faces are resistant to high-temperatures, corrosion, wearing and have good sealing properties. They are widely used in spacecraft, machinery, metallurgy, printing and dyeing, foodstuff, pharmaceutical, auto industry and so forth.
Silicon
Silicon has excellent corrosion resistance, high mechanical strength, high thermal conductivity and good self-lubrication. They are used as seal faces, bearings and tubes in spacecraft, machinery, metallurgy, printing and dyeing, foodstuff, pharmaceutical, auto industry and so forth. When these faces are combined with graphite faces, friction is at a minimal.
Tungsten
Tungsten carbide is widely used as seal faces with high wear resistance, high fractural strength, high thermal conductivity and low heat expansion co-efficient. It is a durable material that resists heat and fracturing.
Common Elastomers
Nitrile
Nitrile rubber (NBR) is the general term for Acrylonitrile Butadiene Copolymer and there are a number of common variations of nitrile compounds. NBR is one of the most commonly used sealing elastomers due to its resistance to petroleum-based fuels and lubricants, silicone greases, hydraulic fluids, water and alcohols. It provides a good balance of desirable working properties including low compression set, high tensile strength, and high abrasion resistance. It is also priced relatively low.
Temperature range:
Standard Low Temp: -35 ˚C
Standard High Temp: 120 ˚C
Viton
Viton rubber, a specific fluoroelastomer polymer (FKM), was introduced into the aerospace industry in 1957 to fulfil its needs for a high-performance elastomer. Following its introduction, the usage of Viton spread quickly to other industries including the automotive, appliance, chemical, and fluid power industries thanks to its natural resistance to both fuel and oil. Viton has a strong reputation as a high-performance rubber in high temperatures, ozone, weather, oxygen, mineral oils, hydraulic fluids, aromatics and many organic solvents and chemicals.
Temperature range:
Standard Low Temp: -26˚C
Standard High Temp: 232˚C
EPDM
Ethylene Propylene Rubber (EPR) is a Copolymer of ethylene and propylene. EPDM is a terpolymer or ethylene and propylene with a small amount of a third monomer to permit vulcanisation with Sulphur. This rubber is useful for a number of industries, such as automobile assembly and water purification systems, due to its excellent resistance to ozone, sunlight and weathering. It also has very good flexibility at low temperatures, good chemical resistance and electrical insulation property.
Temperature range:
Standard Low Temp: -55˚C
Standard High Temp: 125˚C