Performances of aluminium alloy in seawater using various concentration of tapioca starch

Abstract

Currently, there are many studies about the use of inhibitors for the control of corrosion of metals and alloys which are in contact with aggressive environment. It is need to point out the importance of cheap and safe inhibitor of corrosion. Therefore, inhibitors that are from natural sources have become important as they are environmentally acceptable, readily available and renewable sources. Aluminium was chosen as experimental material because it is widely used for many applications in engineering material as it has many advantages. This study used tapioca starch because it offers interesting possibilities for corrosion inhibitor and it is safe to use, low cost, availability, and high solubility in seawater. Low concentration of tapioca starch which is 200, 400, 600, and 800ppm was used. The characterization of the corrosion was performed by using weight loss, potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The percentage of inhibition efficiency (IE%) was calculated by using equation and this study showed the corrosion rate decrease by increasing concentration of the tapioca starch. Tapioca starch used is believed to form a surface layer as it protects AA5083 from reacting to the environment. This is confirmed by doing analysis of SEM that show the formation of precipitates of tapioca starch on the metal surface, which reduced the overall corrosion reaction.