Electrochemical investigation of the corrosion susceptibility of hybrid reinforced Al6063 with SiC and PKSA in 1.0 M sulfuric acid environment

Abstract

The recycling of agro‐waste as complementary reinforcements has received significant recognition in the development of aluminium matrix composites. Hence, this study examines the corrosion behavior of Al6063 reinforced with hybrid SiC/PKSA (palm kernel shell ash) particles. Through various ratios of SiC and PKSA particles in Al6063 alloy, composites were fabricated by double stir casting. Samples were cut and metallographically prepared for 1 M H2SO4 solution corrosion experiments. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic analyses were employed. The composites corroded initially at relatively high rates, gradually declining during long immersion times in the acidic solution. The intersection of reinforcements at the general surfaces of the composites where flawed oxide skins predominate acted as active sites for corrosion initiation. From potentiodynamic polarization studies, the corrosion currents increased with time for all specimens, with A9 being 1075.65 μA/cm2 at 72 h as against 857.99 μA/cm2 at 24 h of measurement. The corrosion potentials for all the specimens hovered around −654.00 to −647.22 mV. Bode plots revealed similar electrochemical reactions over all the substrates' surfaces. The relative corrosion resistance by the specimen depends on the oxide films' nature as the cathodic interfacial reinforcements dropped off into the acidic environment.

Agro waste reinforcement of metal matrix composites, a veritable sustainable engineering achievement, or an effort in futility? A critical review

“…Palanivendhan and Chandradass [43] reported excellent corrosion behaviour of BN/Lemon grass ash (LGA) reinforced ADC12 alloy in a 3.5% NaCl solution (figure 9(b)). Additionally, Ikubanni et al [188] reported a decline in the corrosion rate of Palm kernel shell ash (PKSA)/SiC reinforced AA6063 hybrid composite for long immersion time in 1.0 M H 2 SO 4 environment. These results suggest that AWs-based reinforced hybrid HAMCs will perform optimally in saline solutions and poorly in acidic environments.…”