Material
FFKM
Perfluoroelastomer (FFKM) properties and chemical resistance.
Polymer
Perfluoroelastomer (FFKM, e.g. Kalrez™)
Temperature range
−15 °C … +300 °C
Hardness
70–90 Shore A
Overview
FFKM offers near-universal chemical resistance together with extreme heat resistance, approaching PTFE-like inertness while remaining an elastomer. It is used where no other seal survives — at a significantly higher cost.
Strengths
- • Broadest chemical resistance of any elastomer
- • Continuous service to +300 °C and beyond
- • Very low outgassing (semiconductor grade)
- • Resists aggressive solvents, acids and bases
Limitations
- • Very high material cost
- • Limited low-temperature capability
- • Lower mechanical strength than FKM
- • Long lead time for specialised grades
Compatible media
Ketones, esters, ethersStrong acids & basesAggressive solventsHigh-temperature process fluids
Media to avoid
A few fluorinated fluidsMolten alkali metals
Typical applications
Semiconductor processingChemical & pharmaceutical plantsOil & gas (sour service)Aerospace critical seals
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