The Applications Of Fluoroelastomers. Why Use FKM?
Mar 3, 2020
Fluorocarbon elastomers, commonly known as FKM, are a key component in industries that are exposed to harsh chemical conditions, ozone attacks and intense temperatures. FKM can handle environments from as low as -40°C and as high as 250°C – or higher for short periods.
FKM has been shown to contain a high ratio of fluorine to hydrogen content which gives them an extraordinarily strong resistance to a wide range of industrial chemicals including acids, steam, methanol, petroleum-based and silicone oils, diesel fuels and other highly polar fluids.
The strong carbon-fluorine bonds maintain their stability and help prevent chemical saturation even when exposed to high-temperature conditions.
As a general rule, the more carbon-fluorine content in the product, the more resistant it is to corrosive agents. Lower viscosity polymers are typically used for extrusions or to help mould flow for complex part configurations.
Applications for FKM
Fluoroelastomer was originally developed by DuPont in 1957 to meet the demands of the aerospace industry that required high-performance sealing applications.
Other industries subsequently found a need for FKM including national defence, automobile and other mechanical devices requiring maximum resistance to elevated temperatures and corrosive fluids.
Today’s FKM’s are manufactured with more fluorine atoms that shield the polymer backbone and provide products with a much broader solvent resistance and even greater thermal stability than standard fluoroelastomers.
Uses for FKM in Aerospace and Automobile
Advancements in gas turbine engines are pushing fluoroelastomers to their thermal limits. As vehicles, aircraft and ships become more powerful and energy-efficient they require durable components that are more reliable, operate safely and last longer.
FKM polymers provide a solution to both the aerospace and automobile industries and are also used by the Ministry of Defence to build high-performance machinery that requires premium quality parts to provide stability in high endurance conditions. FKM compounds typically range from 55 to 90 durometer.
Typical uses for FKM in the aeronautical industry include O-rings, gaskets, shafts, fuel hoses, joints, and other electrical connector components that are subjected to intense temperatures and pressure changes during flights.
In the automotive industry, FKM synthetic rubbers help power high-performance engines that combine oil and chemicals with high temperatures.
Uses of FKM in Cold Conditions
One of the issues with standard FKM rubber is their inability to withstand extremely low temperatures. Most polymer products can only be used down to -25°C. Low-temperature polymers can work down to -40°C.
Low-temperature flexibility refers to the temperature which an elastomer changes from an elastomeric to a hardened state. At this point, the polymer loses its flexibility and will not be able to recover its original condition after being deformed. As a result, leaks become a high risk.
Fluoroelastomers have low-temperature properties that improve the tolerance to extreme cold. Using standard low-temperature polymers can significantly increase the cost of production because you must replace the parts more often.
Because polymers differ in fluorine content, viscosity and curing method, there are many different FKM polymers to choose from. If you’re not sure what you need, contact a knowledgeable member of our team and we’ll guide you in the right direction.