Perfluoroelastomer - FFKM
Common Names: FFKM / Perfluoroelastomer
Chemical Name: Perfluoroelastomer
ASTM D1418 Designation: FFKM
ISO/DIN 1629 Designation: FFPM
ASTM D2000/SAE J200 Type, Class: N/A
Description: FFKM materials combine the outstanding heat and chemical resistance of PTFE with the elastic behaviour of FKM elastomers. FFKM materials are very expensive and are typically used only when absolutely needed.
Key Use(s): Seals for use in the chemical and petroleum industries as well as for the manufacturing of semiconductors and analytical and process instruments. It is also used for high temperature applications and for paint and coating operations.
Standard Compound: -25°C (-13°F) to 316°C (600°F)
Hardness (Shore A): 65 to 90
Features: FFKM combines the toughness of an elastomeric material with the chemical inertness of Teflon™. It resists attack by nearly all chemical reagents and provides long-term service where corrosive additives can cause other elastomers to swell or degrade. In addition, FFKM parts are less likely to cold flow than Teflon seals.
Limitations: Withstanding degradation by virtually all chemicals, FFKM can swell significantly when exposed to some fluorinated solvents, fully halogenated freons and uranium hexafluoride. In addition, FFKM parts should not be exposed to molten or gaseous alkali metals.
As the thermal coefficient of expansion for FFKM is stated by the manufacturer to be "about 50% greater than for fluoroelastomers", gland volume may have to be increased to allow for this expansion in elevated temperature situations.