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Abstract
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This work aims to develop environmentally friendly silane coating reinforced with a hybrid pigment to protect
mild steel against corrosion in a saline environment. Fourier-transform infrared (FT-IR) spectroscopy, contact
angle (CA) measurement, field emission scanning electron microscopy (FE-SEM), and energy dispersive spectroscopy
(EDS) were used to study the coating structure and its protective mechanisms. The presence of hybrid
pigment led to the conversion of more Si–OH groups into Si–O–Si groups during condensation process increasing
the cross-linking density of silane; the enhanced cross-linking yields the coating with lower defects and stronger
adhesion to substrate and so improved barrier and anti-corrosion properties. The EIS test showed that the charge
transfer resistance (Rct) for the sample coated with hybrid sol-gel silane increases up to 40 % for all immersion
times after the incorporation of the hybrid pigment into the coating matrix. The polarization test showed that the
corrosion current density (icorr) value decreases from 1.40 to 0.56 μA/cm2 after 120 h of exposure to the saline
solution when the hybrid pigment is added to the coating matrix. These results demonstrate the inhibitive action
of the hybrid pigment enhancing the protective performance of the sol-gel silane coating.
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