Solid particle erosion evaluation of automotive paint coatings under the influence of artificial weathering

Abstract

Solid particle erosion (SPE) is one of the most critical tribological problems causing damage to automotive paint coatings. The correct characterization of SPE and resistance against it makes the possible extended service life of the coating, increasing the resale value of cars. Car manufacturers and paint industries have developed new techniques to apply coatings and coatings that improve the initial and long-term appearance, scratch performance, and durability of coatings. Several works have focused on studying the degradation and performance of paint coatings. However, there needs to be more understanding of wear progress under different environmental degradation conditions. This study investigates the mechanisms and resistance of erosive wear of actual automotive paint coatings before and after exposure to an accelerated weathering process. Steel substrate panels with a typical paint coating system were exposed to weathering degradation by UV and immersion in an artificial acid rain solution. The chemical changes induced in the coatings were analyzed by FT-IR spectroscopy. Then erosive tests were carried out using silica sand particles at two different angles of incidence (30° and 90°) and temperatures (25 °C and 60 °C) for both samples (unexposed and weathering conditions). The SPE rate was determined for each coating by mass loss estimation using an analytical balance; meanwhile, wear mechanisms were analyzed in detail by SEM. The results showed decreased SPE resistance promoted by chemical changes in samples exposed to both weathering processes.