Recovery of Al2O3 from hazardous Al waste as a reinforcement particle for high-performance Ni/Al2O3 corrosion resistance coating via ultrasonic-aided supercritical-CO2 electrodeposition

The unprocessed dumping of aluminium wastes in the landscape leads to generation of heat and toxic gases, which are detrimental to the ecosystem. Motivated by the waste-to-wealth notion, we demonstrated the recovery of aluminium oxide nanoparticles (Al2O3NPs) from domestic aluminium wastes via a sonochemical approach and synthesis of nickel/aluminium oxide (Ni/Al2O3) coating via ultrasonic-coupled supercritical carbon dioxide (USSC-CO2) electrodeposition method for higher corrosion resistance performance. The physical characterization and material confirmation of prepared films were examined by microscopic and various spectroscopic techniques. The electrochemical corrosion resistance studies were explored via potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Based on the results, the US-SC-CO2 strategy exposed an improved distribution of Al2O3 NPs assimilation in Ni matrix, higher corrosion resistance, and microhardness. The integration of ultrasonic irradiation into the SC-CO2 process promises an enhanced coating quality. Thereby, the novel US-SC-CO2 approach for Ni/Al2O3 synthesis is expected to achieve a sustainable green impact in real world applications.