Adsorption and corrosion inhibition of phytic acid calcium on the copper surface in 3 wt% NaCl solution

•PAC film effectively inhibits the copper from corrosion in 3 wt% NaCl solution.•The adsorption of PAC is successfully described by the Langmuir adsorption isotherm.•Value of ΔGads0 reveals the film formation on the copper surface via chemisorbed fashion.•Raman spectrum elucidates PAC film at the copper surface through PO groups.

The adsorption and corrosion protection effect of phytic acid calcium (PAC) film on the copper surface in 3 wt% NaCl solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Raman spectroscopy. Polarization curves indicate that PAC is a mixed inhibitor, affecting both cathodic and anodic corrosion currents. The inhibition efficiency of PAC film reached 92.53% at an optimized condition. Adsorption of PAC molecules on the surface followed Langmuir adsorption isotherm and the standard Gibbs energy of −37.32 kJ mol−1 indicated a chemisorptive way. Raman studies suggested that PAC molecule chemically anchored at the surface via PO groups.