Synergistic effect of α-alumina integrated silica ceramic nanocomposites prepared using waste beverage cans and rice husk for corrosion protection application

Abstract

In this study, we investigated the synergistic effect of α-alumina-integrated silica nanocomposites as a promising material for corrosion protection. We synthesized these nanocomposites in different proportions (90 wt% silica:10 wt% alumina (AS-1) and 70 wt% silica:30 wt% alumina (AS-2)) via ball milling using rice husk and waste beverage cans as the precursor source. XRD, FTIR and EDX analysis of α-Al2O3 integrated silica nanocomposites revealed distinct peaks corresponding to both silica and α-Al2O3 components, confirming the successful formation of the nanocomposites. FESEM and TEM analyses showed that the α-alumina and silica nanoparticles were agglomerated and inhomogeneous, with sizes ranging from 150 nm to 250 nm. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests showed that pure silica, AS-1, and AS-2 had corrosion rates of 1.7648, 0.4396, and 0.0610 mm/yr, respectively. AS-1 and AS-2 exhibited higher charge transfer resistance (Rct) values of 34.54 KΩ and 48.60 KΩ, respectively, compared to pure silica (24.4 KΩ). Nyquist and Bode plots revealed the improved corrosion resistance of α-alumina-integrated silica nanocomposites compared to pristine silica-based protective coatings on mild steel. It is noted that the amount of α-alumina content enhances the corrosion resistance efficiency of the nanocomposites. The synergistic effect of the α-alumina-integrated silica nanocomposites can be attributed to the improved barrier properties and forming a protective layer on the metal substrate, effectively mitigating the corrosion process.