Anticorrosive Coating of Propolis Extract for CA-50 Carbon Steel Reinforcement

This study investigated the efficiency of the natural anticorrosive coating of propolis extract (PE) on CA-50 carbon steel in a solution that simulates the liquid phase of the concrete pore condition, called cement extract (CE). Fourier transform infrared (FTIR) and high-performance liquid chromatography (HPLC) analyses of the propolis extract identified inhibitory functional groups, with Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) being the predominant component present in the propolis extract (PE). To examine the inhibition capacity of propolis extract on reinforcement, an aqueous solution of 3.5 wt.% NaCl solution was added to the cement extract in the presence and absence of PE. Electrochemical techniques such as open circuit potential, polarization curves and electrochemical impedance spectroscopy were carried out to study corrosion efficiency. Scanning electron microscopy (SEM) was performed to characterize the sample surface. The results show that PE was effective as an anti-corrosion coating for carbon steel in the environment studied, indicating the formation of a protective film with higher stability.