We thought it might be fun to, from time-to-time, revisit some old pieces of content that have lived in the pages of the Gateway Magazine at some point in the last 20+ years of the periodical’s existence. This will also serve as a welcome departure from all the pandemic prose we seem to have been typing up for the past six-months… With that departure in mind and in the spirit of taking “a look back,” let’s move forward (as best we can)! In many ways, the industry has changed greatly, while, in others, it’s “business as usual” where we’re simply looking to continue the grind and get ourselves from point A to point B in a job cycle.
Today we’re going back exactly 20 years to November of 2000 to have a look at “A Gateway Educational Enlightenment Article” that we used to run as space permitted. The pieces were submitted by our readers and capped at around 400 words. The spotlight in November’s issue 20 years ago was on Electroless Nickel & PTFE coatings. So, without further ado, here’s the text verbatim (with some minor formatting changes…)
Electroless Nickel & PTFE
About 17 years ago, the first Electroless Nickel/PTFE (Teflon) coatings were introduced. The target was to obtain a coating with uniform properties in all three dimensions. To achieve optimum properties of a coating, it is necessary for the particles to be evenly distributed so that the anti-adhesion and wear properties of the coating show the same appearance everywhere. This influenced the mechanical and tribological (friction, lubrication, bearing, and hydrodynamic) properties of the coating.
To achieve the “perfect coating” and the required lifetime, it was necessary to modify the electroless nickel electrolyte and the manufacturing of the dispersion to develop an improved proprietary process. Because of the results, EN/PTFE coatings can expect a bright future as solutions to many customers problems. Hard coatings cannot cope with all wear and corrosion problems, and industry has demanded mass tailored and specific problem solving coatings.
Wear Properties
A widely held prejudice is that only hard coatings can solve wear problems. That is correct for abrasive wear, but only for that specific case. For nearly all other tribological problems, a reduction of the coefficient of friction can handle it, and sometimes even better. The main reason for the success is that the forces that could fatigue one or more tribological partners are reduced, so less wear is transferred into the material.
Because of the fatigue behavior of the coating, PTFE and EN particles are broken out of the surface. In the case of the very smooth surface, the small Ni-P particles can increase the wear on the next layer of the coating, and the PTFE balls are simply wiped away. Against that, the PTFE particles remain longer in the area of wear and can be used like ball bearings on the rougher surface. The Ni-P particles are too small to increase the wear on the rough surface.
Corrosion
Galling and corrosion problems are covered best by EN/PTFE dispersion layers. This is because of the anti-adhesive and hydrophobic properties of the surface, and the thermal conductivity of the coating. While ceramic coatings are electrical and thermal insulators, EN/PTFE coatings have electrical and thermal conductivity.
Different Applications for EN/PTFE
New improvements in the coatings have helped in many industries, such as:
- Drilling equipment
- Tools
- Stamps and molds
- Gas meters
- Spiral pumps
- And more…
As an example, an industry utilizing stamp and injection molds would see a very marked improvement in three areas:
- Anti-adhesion
- Time
- And yield
Since improving the chemistry and the deposit, most applications can now be approached successfully.
So, how have things changed as they relate to this “Enlightenment Article”? Not a whole lot. Some coatings have been introduced that are touted as being superior, but, all and all, Electroless Nickel & PTFE remain as they stand, and in good order. To sum it up in 2020:
Electroless Nickel & PTFE is a smooth, and ever tough composite coating that gives a low coefficient of friction without compromising or challenging the cohesion and relative hardness of the coating at large.
The properties of the Electroless Nickel / PTFE mix make the solution an ideal coating in situations where traditional lubricants are unsuitable. Electroless Nickel & PTFE as a solution, also exhibit low sliding wear and anti-galling properties.
Features of Electroless Nickel & PTFE Include:
Low friction & high wear resistance – Solution exhibits a low coefficient of friction as well as good sliding wear characteristics.
Superb anti-galling & anti-seizure – Electroless Nickel & PTFE coatings prevent seizing and galling when pieces and parts are securely fastened together.
Solid hardness profile – The coating(s) offer a good hardness value as plated that can be increased as required with applicable heat treatment renderings.
Application options – Electroless Nickel & PTFE can be taken advantage of for myriad application opportunities such as:
- Tooling molds
- Part molds
- Medical molds
- Connectors and fasteners
- Circuit breakers
- Valve seats and pump bearings
- Machine tools
- Cylinder liners
- Clutches and splines
- Spindles
- And many more…
Fun to revisit, and hey, if you’ve got an “Enlightenment Article” you’d like to submit, please, don’t hesitate, we, and all our readers, love learning about the goings on in the vast world of manufacturing! Email submissions to: chris@thegatewaymag.com
