A few weeks ago we took a look at the value of fluoropolymer coatings and the general treatment process. Now we explain additional advantages and applications of polytetrafluoroethylene. Polytetrafluoroethylene (PTFE) is the polymer most frequently used for dry lubrication. It is an extremely inert material that has a relatively high melting point (617℉). Compared to other polymers PTFE has a lower coefficient of friction — as low as 0.05 — which is largely due to the structure of the polymer molecule that allows the polymer chains to slide easily over each other. This forms a thin lubricating film when other materials slide against a PTFE-coated surface. PTFE’s low surface energy (18.6mN/m) yields its renowned non-stick properties.

Nimet Industries uses PTFE technology in the Nituff® process, which combines PTFE with aluminum oxide to form a coating for aluminum and its alloys. The result: a self-curing, self-lubricating surface with wear and corrosion properties superior to standard hardcoat anodizing. In the Nituff® process, Nimet electrochemically oxidizes the outer surface of the aluminum substrate to grow crystals of aluminum oxide, which become an integral part of the structure.

Before the crystals are completely formed, sub-micron particles of Teflon® PTFE are introduced into the aluminum oxide matrix. The coating is .002 inch thick, .001 inch below the surface and .001 inch above. This hard, abrasion-resistant coating has a non-conductive surface with breakdown voltage exceeding 2,000 volts.

Combined with traditional metal anodizing or plating, PTFE adds corrosion protection and self-lubrication, among other properties, to base metals. In corrosion-resistance testing, the Nituff® coating survives more than 2,000 hours in a five percent salt spray as compared to the 850 hours typical for hardcoat anodizing alone.

PTFE at Nimet Industries

Nimet enlists PTFE composite coatings to serve industries from dental to defense. USDA-approved Nituff® is used to treat medical, dental, and food processing equipment to provide self-lubrication without oils or greases. It also provides abrasion resistance in components used in high-speed machinery that handles textiles or paper; its dry lubrication properties eliminate the need for lubricants that could stain paper or textiles.

Fluoropolymers coatings can also be used with other metals and in electroless nickel processes. Electroless nickel PTFE coatings like Nimet’s NiCoTef® are used in a variety of ways.

  • To repel water, oil, and dirt
  • To enhance the release of properties of molds for plastic and rubber components
  • To provide dry lubrication and reduce friction
  • To improve wear resistance
  • To increase corrosion protection

Nimet offers other combinations of metal surface treatments and penetrated fluoropolymer particles. Contact us with specific needs or questions.

Advertisement