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For the "Fiombonan'ny Fiangonana Kristiana eto Madagasikara" (FFKM) see Council of Christian Churches in Madagascar.

FFKMs (by ASTM 1418 standard) (equivalent to FFPMs by ISO/DIN 1629 standard) are perfluoroelastomeric compounds containing an even higher amount of fluorine than FKM fluoroelastomers.

They have improved resistance to high temperatures [1] [2] and chemicals and even withstand environments where Oxygen-Plasma are present for many hours. Certain grades have a maximum continuous service temperature of 327 °C (621 °F). They are commonly used to make O-rings and gaskets that are used in applications that involve contact with hydrocarbons or highly corrosive fluids, or when a wide range of temperatures is encountered.

For vacuum applications, demanding very low contamination (out-gassing and particle emission) as well as high temperature operation (200–300 °C) for prolonged out-baking or processing times and where a copper or metal sealing is not possible or very inconvenient/expensive, a custom-made, clean-room manufactured, sealing such as Kalrez® 9100,[3] SCVBR[4] or Perlast[5] can be used. After manufacturing, they are O-plasma vacuum cleaned (and/or vacuum baked) to reach out-gassing performance similar to Teflon while reaching vacuum leak tightness (permeability rates) similar to FKM (Viton) compounds.[6] This combination of properties allows FFKM seals to reach well into UHV pressures without the use of metal sealing. However, they are significantly more expensive than standard FKM O-rings.


  1. ^ https://newdealseals.com/app/uploads/2020/10/NDS-Fluorezi-_v5.pdf
  2. ^ E. I. DuPont, Kalrez Product Brochure.
  3. ^ http://www2.dupont.com/Kalrez/en_US/pfo/assets/downloads/Kalrez%209100%20for%20Photovoltaic.pdf
  4. ^ "Semiconductor Industry | O-Ring".
  5. ^ "Perlast Perfluoroelastomer FFKM Seals and O Rings - a Rubber Form of PTFE". www.prepol.com. Retrieved 2017-03-02.
  6. ^ "viton sheet gasket material". www.gasketing.net.