Adhesion
What is adhesion?
Adhesion refers to the bond between two surfaces in contact with each other—in this case, between the elastomer of the O-ring and the material of the groove or mating surface. It differs from cohesion, which describes the internal bonding within a material. In O-rings, adhesion occurs particularly when the seal is under pressure for an extended period or is installed at higher temperatures. The material can then stick to the mating surface.
Why Adhesion Is Important for O-Rings
In static applications, a certain degree of adhesion is usually not a problem. With dynamic seals, however, excessive adhesion can lead to the so-called stick-slip effect: The seal briefly sticks, then breaks away abruptly and slides. This increases friction and wear and can cause the motion to become uneven. Furthermore, when a stuck seal is released, there is a risk that material will remain on the mating surface. Proper lubrication with assembly grease and an appropriate surface finish reduce unwanted adhesion.
- Adhesion refers to the O-ring's adhesion to its mating surface, not its internal cohesion.
- Excessive adhesion promotes the stick-slip effect in dynamic seals.
- Assembly grease and a good surface finish limit adhesion.
For moving seals, we recommend selecting the appropriate material from our product line. You can find the correct surface finish for the mating surface in the tolerance specifications.
You can find the right material for your application in our product range.