A Comparative Investigation of the Tribological and the Mechanical Behavior of Polyester Powder Coatings Filled with Graphite Depending on the Filling Percentage and the Size of the Graphite Particles

Composite coatings are used in order to reduce the friction and protect contacting surfaces against wear with good adhesive to substrate. The present study deals with two sizes of solid particles used in composite coatings. As received graphite G1, the mean size is 20 µm and the crushed one, obtained by ball mill, is 10 µm. The resulting tribological behavior and micromechanical properties were discussed and compared. As expected, the smaller the particle size the greater reduction in the coefficient of the friction and wear rate. The experimental findings show that adding 5 wt% of crushed graphite provide similar COF than when introducing 10 wt% of as received graphite. Coatings scratch behavior is affected by the size and percentage of fillers inside the polyester matrix. In fact, the scratch resistance is observed with polyester coatings filled at 5 wt% G2 and 10 wt% G1