Materials Engineering in September 1991 ran an article titled “Synergistic Fluoropolymer Coatings,” which discusses the advantages of the combined processes of metal anodization and infusion of fluoropolymers. Although the article, written by Tim Stevens, is nearly 20 years old, its basic precepts and data remain relevant, so we offer an overview of the article here.

Summary of “Synergistic Fluoropolymer Coatings”

Synergistic fluoropolymer coatings are the result of infusing a low-friction fluoropolymer like Teflon into an aluminum oxide, which makes the fluoropolymer a major ingredient in the top coating rather than establishing it as another layer in and of itself. What this means is a number of advantages in the final product:

  • Self-lubrication
  • Greater corrosion resistance
  • A low coefficient of friction
  • Increased hardness (Rockwell C62)
  • Chemical resistance
  • Improved dielectric properties

Nituff® is such a coating. It combines polytetrafluoroethylene (PTFE) with aluminum oxide and ultimately yields a surface far superior to standard hardcoat anodizing.

Process Overview

An aluminum surface that will be treated undergoes these steps:

  1. The aluminum surface is electrochemically oxidized to stimulate growth of aluminum oxide crystals. (This is part of the standard anodization process.)
  2. Sub-micron particles of PTFE are introduced. (The timing of this introduction is critical: crystals must be only partially formed.)
  3. Completely formed crystals have trapped the PTFE particles, integrating them into the coating. (This forms the final coating.)

The coating that results, as noted above, has a Rockwell hardness of C62. It also has a nonconductive surface that withstands more than 2,000 volts and more than 2,000 hours in a 5% salt spray, where typical hardcoat anodizing withstands only 350 hours in a 5% salt spray. Such a coating has many applications, such as military and culinary, because its non-reflective surface also repels dirt.

Synergistic Fluoropolymer Coatings at Nimet Industries

Nimet Industries has been in the business of precision metal finishing for more than 45 years. We have seen first-hand the benefits that our proprietary process afford our customers, and we encourage you to contact us with questions or to discuss how we can put our expertise to work for you.

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