"FKM" and "Viton" are not two different materials in a strict chemical sense — Viton is a brand name, while FKM is the generic technical designation for the entire family of materials it belongs to. Understanding the relationship requires a bit of context:
FKM (Fluoroelastomer) FKM is the ASTM/ISO abbreviation for fluorocarbon or fluoroelastomer rubber — a broad category of synthetic rubbers containing fluorine, prized for excellent resistance to heat, oil, fuel, and many chemicals. FKM is a generic term, much like "polyester" or "nylon," and covers many different grades and formulations (standard FKM, low-temperature FKM, high-fluorine FKM for extra chemical resistance, peroxide-cured vs. bisphenol-cured types, etc.) produced by numerous manufacturers worldwide.
Viton Viton is a registered trademark, originally developed by DuPont and now owned by Chemours, for a specific line of fluoroelastomer products. In other words, Viton is an FKM — it's one company's branded product within that broader material family. Because DuPont pioneered fluoroelastomers and marketed them heavily, "Viton" became a widely used (if technically imprecise) generic term in industry, similar to how "Kleenex" is often used for facial tissue in general.
Practical differences
- Origin/Branding: FKM = generic material class; Viton = a specific manufacturer's trademarked product line within that class.
- Quality and specification: Viton-branded compounds are manufactured to Chemours' proprietary formulations and quality standards. Generic or "off-brand" FKM from other suppliers may perform similarly but isn't guaranteed to match Viton's exact specifications, additives, or curing systems.
- Performance: Since Viton is one type of FKM, its performance characteristics (temperature range, chemical resistance) fall within what's typical for FKM materials, though exact properties vary by specific grade, whether it's Viton or another manufacturer's FKM.
- Cost: Viton-branded parts are often priced at a premium due to brand recognition and consistent quality control, while generic FKM alternatives may be less expensive.
For most engineering purposes, when a spec calls for "Viton," an equivalent generic FKM compound can typically serve the same function, provided its specific grade and properties match the application's requirements.