Abrasion behavior of Al2O3-reinforced epoxy resin with different particle sizes

Due to their high strength-to-weight ratio and ease of processing, epoxy resins are widely used in modern composite applications; however, their low wear resistance remains a limitation in demanding service environments. In this study, the improvement of mechanical and tribological performances of composites produced by reinforcing aluminum oxide (Al₂O₃) particles of different sizes into the epoxy matrix was investigated. The epoxy composites were modified with Al₂O₃ particles of 1% by weight in four different size ranges (1–2, 10, 44, and 180–250 μm), which were evenly distributed using ultrasonication. In the tensile test, sample with a particle size of 44 μm exhibited the highest value at 71.7 MPa. Tribological tests were performed in accordance with ASTM G99 standard. Tribological tests were conducted at loads of 5 and 10 N, sliding speeds of 1.75 and 2.25 ms⁻¹, and a fixed sliding distance of 1000 m under dry sliding conditions. The lowest wear loss was observed (0.869 × 10⁻⁹ m³) in the 44 μm sample under a load of 5 N and a speed of 2.25 ms−1. The morphology of surface wear was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). In samples characterized by larger particle sizes, the wear marks had a smoother appearance. The application of a predictive modeling technique allowed the identification of the main factors influencing the wear rate, volumetric loss and coefficient of friction (COF).