Corrosion behaviour of thermal cycled aluminium hybrid composites reinforced with rice husk ash and silicon carbide

The corrosion behaviour of aluminium hybrid composites reinforced with rice husk ash and silicon carbide subjected to thermal cycling has been investigated. Aluminium hybrid composites having 10 wt% reinforcement consisting of silicon carbide (SiC) and rice husk ash (RHA) in weight ratios of 1:0, 3:1, 1:1, 1:3, and 0:1 respectively were produced. The composites were subjected to varying thermal cycles of 6, 12 and 18 from room temperature to 200 °C repeatedly. Potentiodynamic polarization measurements were used to study the corrosion behaviour of the produced composites. The results show that the composites displayed similar polarization curves and passivity characteristics irrespective of the number of thermal cycles both in H2SO4 and NaCl solutions. No consistent trend of corrosion current density changes with increase in thermal cycling was established for composite grades 3:1, 1:1 in H2SO4 and 1:0, 0:1 and 3:1 in NaCl solutions. The hybrid composite grades with a higher RHA content generally exhibited a lower tendency to corrode compared to the other composite grades. Generally, the composites seemed to be structurally stable as they maintained their corrosion resistance levels even after exposure to thermal cycling.