5. Glossary

thermal degradation

Irreversible and undesirable modification of a material's properties due to overheating.

elasticity

Property of a substance that enables it to change length, volume or shape in direct response to a force making such a change, and to return to its original shape when the force is removed.

elastomer; elastomer

Elastic rubbery substance, such as natural or synthetic rubber.

dynamic sealing" surface finish

Relative roughness, generally expressed in µm, of dynamic sealing surfaces (rotating shaft surfaces, sliding rod surfaces, etc.) or seals, especially for hard materials (plastic, carbon, etc.). The smaller the number, the smoother the finish. In dynamic sealing, the roughness parameters Ra, Rz and...