Nano-reinforcement and Synthesis of Al 8090-based Hybrid Composites with B4C and Coconut Shell Charcoal for Enhanced Tribological Performance

This study investigates the tribological properties of Aluminum 8090-based hybrid composites reinforced with 3 wt. % Boron Carbide (B4C) and varying weight percentages (2%, 3%, and 4%) of coconut shell charcoal (CSC) nanoparticles. The composites were fabricated using stir casting and characterized for their density, porosity, hardness, and wear behavior under different operating conditions. The density decreased with increasing CSC content, whereas the porosity remained below 2.37%, indicating effective particle dispersion. The hardness improved with higher CSC loading, reaching 133.1 HV for the 4% CSC composite. Tribological tests were conducted using a pin-on-disk tribometer, varying the applied load (10, 20, and 30 N), temperature (27, 50, and 100 °C), and sliding distance (500, 1000, and 1500 m). The Taguchi method and ANOVA revealed that the sliding distance was the most influential factor for both the wear rate and coefficient of friction (COF), followed by the CSC content. The optimal conditions for minimal wear (0.01422 mm³/m) and COF (0.449) were found to be 10 N, 27 °C, 2% CSC, and 500 m. The 4% CSC composite exhibited the best overall performance, with low porosity (1.99%), high hardness (133.1 HV), and a reduced COF (0.406). SEM-EDS analysis confirmed the uniform dispersion of the B4C and CSC reinforcements within the Al 8090 matrix, with minimal porosity and strong interfacial bonding. The results highlight the potential of Al 8090/B4C/CSC hybrid composites for applications requiring high wear resistance and low friction, such as in aerospace and automotive components.