Improvement in Corrosion Behavior of Al–Ti Alloy by Adding 2 wt% Magnesia and 1 wt% Silicon Carbide
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Aluminum building wire wastes were used to produce Al alloy by adding 4 wt% of titanium. Also, aluminum matrix composite was fabricated by adding 2 wt% MgO–1 wt% SiC to investigate the corrosion behavior of Al–Ti alloy and composite before and after heat treatments. The heat treatments included annealing, normalizing and tempering at 500 °C. The heat treatments led to breaking up the main phase in base alloy (Al3Ti) and occur many reactions involve decomposition of SiC to form Al4C3 and reaction of MgO to form spinel MgO.Al2O3. The fabricated alloy and composite were characterized by XRD, SEM and EDS. Optical microscopy was used to investigate the changes after heat treatments. Corrosion measurement was achieved in seawater by potentiostat at scan rate of 5 mV s−1. Corrosion parameters were measured for base alloy and composite by Tafel extrapolation method. Corrosion potentials were varied after heat treatments due to variation in anodic and cathodic sites on surface, while the corrosion current densities of composite were less than for base alloy due to the role of SiC and MgO particles that led to reduce the anodic sites on metallic surface. Cyclic polarization test showed that the fabricated composite had breakdown potential more positive than for fabricated alloy.