Corrosion resistance studies of aluminium 7075 / SiC composites materials in an acidic environment

The aluminium and silicon carbide-based composite (Al-SiC) material was prepared using commercially available analytical grade Al7075 alloy and SiC. Here the silicon carbide is used as reinforcement particles in the composites. The metal composites were developed using liquid melt techniques (Vortex method). The reinforcement material is introduced in different weight fractions in the range of 0 to 10% in this process. These Al-SiC specimens were used for assessment of its corrosion properties. The acid corrosion experiments were carried out at room temperature (30 ±1oC). The corrosion characteristics were estimated using the conventional weight loss method according to the procedure of ASTM G69-80. The composites performance was evaluated using microstructural analysis and the corrosion resistance tendency in different acidic environmental conditions. The SEM micrographs picture reveals that reinforcement particle was distributed uniformly. The corrosion test was conducted in HCl medium from 0.25N, 0.5N, 1M and 1.5 M respectively. The Al-SiC specimens were dipped in different HCl medium for four days in six experimental baths. Specimens were taken out from each test medium for every 24 hours and tested for its corrosion characteristics. It is observed that the corrosion rate in all HCl medium decreases with an increase in exposure time. This is due to the passivation of the Al-SiC surface induced by aluminium. It was observed that at the 10 w/w % of the aluminium metal matrix composite have higher corrosion resistance than the base alloy.