Corrosion Behaviour study of Plasma Processed LM6 Alloy in Seawater

Aluminium alloys are mostly used in marine, defence, aerospace, automobile industrial sectors, etc. which are increasing at all times due to their good corrosion resistance and high strength compared to weight ratio. In this research work, the corrosion behaviour of plasma melted LM6 alloy was carried out. For the study of the corrosion behaviour, the prepared alloy is held on seawater for 6 weeks, and weight loss/gain in each week was measured. The corrosion mechanism is prominent by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and optical microscope. The microstructure shows that on the surface, isolated pits are formed and the number and size of pits are increased continuously with increasing number week reveal to seawater. The highest hardness value of 81.12 VHN is seen in 3rd week corroded sample. Hardness is found to be the lowest in non-corroded samples, and it increases up to 3rd week reveal in seawater and then decreases due to corrosion phenomena. The main reason is clear to obtain from the XRD, EDX and SEM analysis. The most predominant corrosion mechanism is seen to be pitting corrosion phenomena from the experiment.