Low Friction Coating
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PTFE when applied as a thin, dry surface coating, can achieve very low coefficients of friction. Typical values are 0.08 – 0.2 static and 0.04 – 0.18 dynamic. This is particularly useful at elevated temperatures when wet oils and greases evaporate or attract contamination debris. The thin surface layer can usually be added to existing designs without the need to the change basic engineering tolerances. The coating prevents slip-stick conditions in slow moving mechanisms. It can also smooth out torque values leading to a higher degree of accuracy. It has the ability to overcome “frozen” conditions usually associated with valves. For heavy duty loads, additional lubricating solids such as MoS2 and graphite are needed. For particularly severe abrasive conditions, performance can be enhanced by the addition of fillers to the formulation or the modification of the surface by the application of metal spraying.
Amid the material selection criteria that ranges from reduced cost and weight to ease of assembly, automotive designers and engineers are increasingly asking for materials that improve wear and reduce friction, PTFE coatings hold the solutions to such questions. PTFE materials are integral to the smooth running of mechanism due to their functional properties, which are maintained as a result of the selected coating system. Fluoropolymer materials, such as Teflon® and Xylan® provide the right combination of strength and dimensional stability, as well as additional benefits such as their appealing surface finish where applications demand such requirements.
PTFE is a resin-bonded, thermosetting and used as a dry-film lubricant / easy-clean coating. It is used to reduce friction, prevent scoring and galling, or provide secondary lubrication in the event of failure of the primary (conventional) lubricant.