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.
