Enas  Hussien Ali, Takialdin  A. Himdan, 
    Tannin as Corrosion Inhibitor for Aluminium in Acidic Medium,
    Journal of Engineering and Applied Sciences,
    Volume 15,Issue 17,
    2020,
    Pages 3250-3257,
    ISSN 1816-949x,
    jeasci.2020.3250.3257,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2020.3250.3257)
    Abstract: Corrosion of aluminium in 0.6 mol. dm<sup>&#150;3</sup> NaCl
solution in acidic medium (pH = 1) was investigated in
the absence and presence of different concentrations of
tannin as environmentally friendly corrosion inhibitor
over temperature range (298-313) K. The investigation
involved electrochemical polarization method using
potentiostatic technique and optical microscopy, the
inhibition efficiency increased by increasing inhibitor
concentration but decreased with temperature raising.
Results showed that the inhibition occurs through
adsorption of the inhibitor molecules on the metal surface
and it was found to obey Langmuir adsorption isotherm.
Some thermodynamic parameters (&#916;G<sub>ads</sub>) and activation
Energy (E<sub>a</sub>) were calculated to elaborate the mechanism
of inhibition. The polarization measurements indicated
that tannin is of mixed type. The surface characteristic of
the inhibited and uninhibited metal samples were
investigated by optical microscopy.
    Keywords: Corrosion inhibition;aluminium;tannin;adsorption mechanism;thermodynamic parameters