Lee, Jeong, Joo, and Park from South Korea have published an experimental and numerical analysis of fretting corrosion in electrical coatings.  This was an interesting study dealing with the effect of wear and corrosion on electrical resistance instead of most papers which I read which try to analyze wear loss or fatigue life. 

The contacts studied were made of copper with a tin coating.  The coating wore away quickly and after that the copper substrate began oxidizing and eventually its entire surface was oxidized.  The percentage of surface covered with copper oxide had a large effect on contact resistance as seen in the figure they published.  It appears not to have too detrimental of an effect until the oxidation covers 90 percent of the contact surface.  However, as seen from the modeling results below this happens around 12,000 cycles into the simulation. 

The contact evolution had three stages: first the tin coating is removed.  Second, the copper substrate is exposed.  Third, the contact becomes covered in copper-oxide.  The second two were the primary focus of the Abaqus model.

From the experimental tests the researchers found fretting wear was predominant during the first 8000 cycles when the coating is being removed.  The wear mechanisms were primarily adhesive and abrasive wear.  The fretted area expanded during this time due to the changing contact geometry.  After the coating has worn through fretting corrosion became the primary damage process. 

The fretting corrosion process was modeled using Abaqus in a three-dimensional simulation.  However, not many details of the simulation were given in the paper.  The copper oxide properties were assigned at random locations along the surface using a fortran program. 

• Lee, K.Y., Jeong, D.K., Joo, H.G., Park, Y.W., 2011, “Simulation for fretting corrosion of tin-coated copper contacts,” Materials and Corrosion, Vol. 62, pp. 352-356.