A study of the frictional characteristics of metal and ceramic counterfaces against electro-deposited coatings for use on automotive seat rails

●Zirconia balls show low friction coefficient on an electro-deposited coating.●Zirconia balls maintain higher durability than conventional ones.●Friction coefficient change can be described with friction coefficient itself.●Rail sliding of automotive seats is simulated with a developed testing machine.

An investigation was conducted on the friction coefficient changes when ceramic balls oscillate against a series of epoxy-based cathodic electro-deposited coatings that could be used for automotive components. Reciprocating sliding tests were conducted using ball-on-plate apparatus; balls were made of silicon nitride, zirconia, and AISI 52100 (also known as GB GCr15, DIN 100Cr6, and JIS SUJ2) steel. Plates used for coating substrates were made of cold-reduced high strength steels. The Coulomb friction coefficient was measured under room temperature and ambient humidity. The endurance lives of cathodic electro-deposited coatings against various ball materials are directly compared using a plot of friction coefficient evolution. Using the basis of friction coefficient evolution, electro-deposited coatings maintained higher durability against zirconia than against Si3N4 and AISI 52100 balls. In addition, the frictional behavior is analyzed using a form of Kachanov-type damage law. It is concluded that the growth rate of the friction coefficient can be represented by the damage parameters in the law.