Fretting Corrosion: Resistance of Materials & Accelerated Life Test

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What about brass?The material is brass and it's yielding under the impact. The materials needed for this application are copper and nickel, but since the ball is rarely hitting the contacts the nickel is not necessary. The process is driven by the impact energy. The ball is made of brass and nickel. The ball is plated with nickel. The ball is in contact with the contacts. The ball is in a humid environment. The ball is in a metal tube. The ball is subjected to temperature variations. The ball is subjected to mechanical vibration. The ball is subjected to moisture. The ball is not sealed from atmospheric oxygen. The ball is subjected to temperature variations. The
  • #1
Fretting Corrosion

I am researching a fretting corrosion problem and I am looking for resources on the relative resistance of materials to this phenomenon as the material on this subject seems very limited. The application is a rolling ball switch, which impacts the tube sidewall due to vibration. The materials must be conductive, able to withstand the stress of the vibration impacts, yet minimize oxides breaking off which cause abrasion.

The historical metal used in this application was brass. Calculations using a Hertzian model indicate the yield strength is being exceeded and the formed oxide particles are causing high resistance and abrasion.

Plated materials such as chrome and nickel meet the needed yield strength but I have not found any information on the surface oxides of these materials in regards to fretting resistance so proper selection of material is impossible. If I were to use an empirical approach I would need insight into an appropriate accelerated life test.

Any thoughts would be appreciated on this subject.
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  • #3
Yes the part is very similar to these parts you list. Unfortunately the part is not sealed from atmospheric oxygen. Both the tube and ball are brass but the ball has a nickel plate with a gold flash. The ball rarely hits the contacts so this is not the wear problem area. In the attached picture, you can see the lovely fretting oxide buildup and the channel worn by the ball in the tube sidewall.

Nickel is a material I have considered but once both parts are plated with nickel will the nickel oxide protecting the surface now break off causing similar erosion? This is why I am curious on relative ratings of materials to fretting corrosion. Currently, the nickel plating remains intact but I assume this is mostly due to Nickel being much harder then the oxides of copper and zinc fretted from the brass. Thus, the current weakest link is the brass tube.


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  • #4
IIRC, Cu and Zn oxides are more friable than oxides of Ni or Cr. In steels, the Cr oxides is more tenacious. Ideally one has a thin layer of oxide - nm's rather than microns.

Of course, Ni and Cr plating can various in quality.

At what temperature does the switch function. Variations and cycling in thermal expansion can be problematic.
  • #5
The switch temperature will very on a daily basis by about 30C.

I have calculated under worst case conditions that the ball’s vibration energy may exert a force of 52 N on the wall during impact at a 4.5e-6 m penetration depth calculated from the Hertzian contact model. This may disrupt the oxides as I assume they won’t like this flexure.

The fretting process is mysterious as I see once source stating that temperature may not greatly affect the process as it is driven by the mechanical impact energy. Also, the same source indicates moisture may impede rather then facilitate the process as a possible lubrication action. Both seem contrary to normal corrosion processes. This article, however, was discussing iron oxides.

What is fretting corrosion?

Fretting corrosion is a type of corrosion that occurs when two surfaces are in contact and undergo small repetitive movements. This can lead to the degradation of the material and can occur in various environments, such as in the presence of moisture or in high temperatures.

What factors affect the resistance of materials to fretting corrosion?

The resistance of materials to fretting corrosion can be affected by various factors, such as the material's composition, surface finish, and the presence of a protective coating. The type of environment and the severity of the fretting conditions also play a role in the material's resistance.

How is the resistance of materials to fretting corrosion tested?

The resistance of materials to fretting corrosion can be tested through an accelerated life test, where the material is subjected to simulated fretting conditions in a controlled environment. This allows for the evaluation of the material's performance and the prediction of its lifespan.

What are some common materials that are resistant to fretting corrosion?

Some common materials that are resistant to fretting corrosion include stainless steel, titanium, and nickel-based alloys. These materials have a high strength and are able to withstand the repetitive movements and corrosive environment without significant degradation.

How can fretting corrosion be prevented?

Fretting corrosion can be prevented by using materials with high resistance, such as the ones mentioned above, and by applying protective coatings. Proper design and maintenance of the components can also help prevent fretting corrosion by reducing the amount of movement and stress on the surfaces.

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