Unveiling corrosion inhibition properties of the Cupressus Arizonica leaves essential oil for carbon steel in 1.0 M HCl

Corrosion scientist/engineers are showing great research interest in developing green corrosion inhibitors of plant origin.It has been reported that plant extracts possess good inhibitive characteristics, with little or no negative impact on the environment.In this work, accurate identification of the Cupressus arizonica leaves essential oil (CAEO) was obtained by hydrodistillation.Gas chromatography-mass spectrophotometer (GCMS) was used to identify its chemical constitution, which indicated the presence of 21.27%, 19.88%, 9.39%, 5.84% and 4.76% of сis-muurola-4( 14),5-diene, terpin-4-ol, α-Pinene, -cadinene and epi-α-muurolol, respectively.The corrosion inhibition properties of CAEO for carbon steel (CS) in 1.0 M HCl were evaluated using weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS).Results revealed that Cupressus arizonica leaves essential oil (CAEO) has an excellent inhibiting effect on the CS in 1.0 M HCl solution.The protection efficiency increases with increasing inhibitor concentration to attain 95% at 500 ppm.Potentiodynamic polarization studies revealed that CAEO acts primarily as a mixedtype inhibitor.The effect of temperature on the corrosion inhibition properties indicated a decrease in the inhibition efficiency from 92% (298 K) to 72% (328 K).Electrochemical impedance spectroscopy measurements showed that adsorbed molecules of CAEO formed a protective film on the carbon steel surface in 1.0 M HCl.