This page defines terminology commonly used when discussing materials, elastomers, and seal compatibility in lubrication systems. Terms are presented to support interpretation of technical documentation, specifications, and equipment design references.
Compatibility is influenced by material composition, operating temperature, pressure, fluid chemistry, and service conditions. Terminology alone does not determine suitability. Confirmation against original equipment manufacturer documentation is required before changes are implemented.
Materials and compatibility terminology
Compatibility
The ability of a material to maintain its physical and functional properties when exposed to a lubricant under defined operating conditions.
Elastomer
A polymer material with elastic properties commonly used in seals, hoses, gaskets, and flexible components.
Nitrile rubber (NBR)
A commonly used elastomer offering resistance to many mineral oils, with performance influenced by temperature and formulation.
Fluoroelastomer (FKM)
An elastomer known for resistance to higher temperatures and a wide range of fluids, often used in demanding applications.
Hydrogenated nitrile rubber (HNBR)
A modified nitrile elastomer providing improved heat and chemical resistance compared to standard NBR.
Polyurethane (PU)
A material used for seals and components where abrasion resistance and mechanical strength are required.
Swelling
An increase in material volume resulting from fluid absorption, which may affect seal performance.
Hardness change
Variation in material hardness following exposure to a lubricant, potentially influencing sealing effectiveness.
Extraction
The removal of plasticisers or additives from a material by a lubricant, which can lead to embrittlement.
Service conditions
The combination of temperature, pressure, motion, and exposure time influencing material behaviour in use.