Statistical Determination of a Fretting-Induced Failure of an Electro-Deposited Coating

Abstract

This paper describes statistical determination of fretting-induced failure of an electro-deposited coating. A fretting test is conducted using a ball-on-flat plate configuration. During a test, a frictional force is measured, along with the relative displacement between an AISI52100 ball and a coated flat specimen. Measured data are analyzed with statistical process control tools; a frictional force versus number of fretting cycles is plotted on a control chart. On the control chart, critical number of cycles to coating failure is statistically determined. Fretted surfaces are observed after interrupting a series of fretting tests. Worn surface images and wear profiles provide that the increase on the kinetic friction coefficient after a steady-state sliding is attributed to the substrate enlarged at a contact surface. There is a good agreement between observation of worn surfaces and statistical determination for fretting-induced coating failure.

Literature Review on Fretting Wear and Contact Mechanics of Tribological Coatings

“…Figure 4 shows an example of friction coefficient evolutions of a coated system and of an uncoated system. An AISI 52100 steel ball was slid over the substrate of a high strength steel plate with an imposed displacement of 0.3 mm [23]. The friction coefficient came to steady after the running-in period.…”

Determination of Nonconductive Coating Thickness Using Electrical Contact Conductance and Surface Profile

“…Electrodeposited coating used for automotive components maintains the variance of its thickness [6,7]. Initial coating thickness in a single specimen ranges from a few microns to a few dozen microns.…”