Corrosion characteristics of cast aluminum alloy—3 wt% graphite particulate composites in different environments.

The corrosion behaviour of cast aluminum alloy (LM 13)—3 wt% graphite particulate composite has been investigated in oil and marine environments by a weight loss method. The room temperature corrosion behaviour of this composite has also been studied by potentiodynamic polarization measurements in sea water. Results have shown that in a marine environment, the rate of corrosion of particulate composite is higher than the base alloy and aluminum. The high corrosion rate of particulate composite in marine environment is possibly due to the graphite particles being cathodic relative to the matrix thus leading to galvanic corrosion in the presence of an electrolyte. However, this particulate composite did not show any sign of corrosion in the engine oil SAE-40 (fresh and used) at 150°C, indicating that it can safely be used in this environment