The third-generation biodiesel blends corrosion susceptibility of oxide particle-reinforced Si-rich aluminum alloy matrix composites

Abstract The study of a stir cast Al356-Nb2O5)P composite immersed in third-generation microalgal-derived biodiesel blends with enhanced plasma electrolyte oxidation surface modification revealed the corrosion susceptibility and possible by-product formation. The effect of (oxide)P reinforcement and mixed-oxide surface coatings were studied separately and cumulatively. Samples were immersed in different biodiesel and petrodiesel blends for up to 3000 h, and their corrosion and electrochemical behavior was studied. Although some weight change was recorded in all samples, the corrosion rates significantly decreased from 1.8 to 1.3 by 10 wt% Nb2O5)P reinforcement, which further decreased 10 times after surface modification. Electron microscopy revealed primary fine-grained microstructure with low porosity content of fine and needlelike dendritic structures in composites and irregular volcanic with scattered micropores and microcracks in surface-modified composites that changed to corrosion spots and flake-covered microcracks after immersion.