Corrosion Behavior of AA70 Reinforced Zea mays Husk Particle in NaCl/H2SO4 Concentrations

The effects of Zea mays husk particle and heat treatment on the corrosion behavior of AA70 matrix composite in 1.5 wt.% NaCl/0.0125 M H2SO4 concentrations were studied using an electrochemical technique and optical microscopy. Results showed that the samples had similar anodic-cathodic polarization behavior after heat treatment, with no passivation. However, the heat-treated AA70 matrix composites were more corrosion-resistant than the untreated AA70 matrix composite material in 1.5 wt.% NaCl/0.0125 M H2SO4 concentrations. The composite with 15 wt.% Zea mays husk and a particle size of 300 μm reinforced AA70 matrix revealed the least corrosive tendency and is the most thermodynamically stable in chloride and sulphate ions conditions. Therefore, the corrosion behavior of heat-treated AA70 matrix composites was better compared to that of AA70 material in 1.5 wt.% NaCl/0.0125 M H2SO4 solution. Furthermore, the presence of a high concentration of aggressive chloride ions increases the corrosion susceptibility, and the Zea mays husk particle breaks down the stable oxide film, resulting in increased chloride ion adsorption. The optical microscopy examination suggested the presence of localized corrosion on the material surface.