Corrosion inhibitor is an suitable and economical method to control the corrosion of metals in acidic environments. In this regard, green corrosion inhibitors based on plant essential oils have received a lot of attention as a usable alternative to common synthetic corrosion inhibitors, which are mostly not environmentally friendly. The presence of active compounds in eucalyptus essential oil has made it a source of green inhibitors in steel corrosion control. In this study, the inhibitory performance of eucalyptus essential oil has been investigated by extracting essential oils using steam method, electrochemical tests and surface analysis methods. Therefore, eucalyptus leaf essential oil has been used as a green inhibitor in the corrosive environment of sulfuric acid and hydrochloric acid to check the reduction of metal corrosion in this environment GC-Mass device was used to investigate the compounds present in the eucalyptus plant. The effect of steel corrosion inhibition by essential oils was investigated using weight measurement methods, electrochemical impedance spectroscopy and absorption isotherms and the results of metal immersed in acid solution with different concentrations were compared in the absence of inhibitor. The results of the tests showed that this substance has a good performance as an inhibitor and the percentage of inhibition on steel corrosion will increase with increasing concentration. The absorption of eucalyptus essential oil on steel follows the absorption isotherm and the amount of free energy of absorption indicates the spontaneous absorption of this substance with the predominance of chemical absorption on the surface.

Technological advances have provided new ways of combating corrosion. Corrosion inhibitors are one means of protection for reinforced concrete structures. The effectiveness of commercially available inhibitor for concrete has been investigated. This study focuses on the effects of benzotriazole inhibitor on ordinary concrete and high performance concrete.The strength and durability property of different dosage of specimens without and with inhibitors on ordinary concrete and high performance concrete was compared. Corrosion tests such as Alternative Current (AC) impedance, Open circuit potential, Long term Potential Resistance (LPR) sweep, Custom sweep, and Half-cell potential were also conducted and compared with ordinary and high performance concrete without and with benzotriazole inhibitor. The inhibitor shows better performance strength, durability and good corrosive resistance.

Corrosion mitigation remains a critical challenge in industries utilizing aluminium (Al), particularly in acidic environments where material degradation can compromise structural integrity and operational efficiency. The effectiveness of Polyvinyl Alcohol (PVA) as a corrosion inhibitor for Al in 1 M sulfuric acid (H₂SO₄) was evaluated through weight loss and polarization techniques. The study was conducted at three different temperatures (25 °C, 35 °C, and 45 °C) and varying concentrations of PVA (300, 450, and 600 ppm) to assess its inhibition efficiency. Results indicated that the inhibition efficiency increased with higher PVA concentrations, achieving maximum values of 90%, 88%, and 86% at 600 ppm for the respective temperatures. However, inhibition efficiency was found to decrease slightly with increasing temperature. Polarization studies revealed that PVA acted as a mixed-type inhibitor, reducing both anodic and cathodic currents. The maximum inhibition efficiency at 25°C was 91% as determined by polarization, with a corresponding reduction in corrosion current from 264.12 mA/cm² (blank) to 23.08 mA/cm² at 600 ppm. The study demonstrates the potential of PVA as an eco-friendly corrosion inhibitor for Al in acidic environments, as its performance is significantly influenced by both temperature and concentration.

The performance of an Imidazoline based commercial corrosion inhibitor on CO2 corrosion of mild steel was investigated in a Cl- containing solution employing linear polarization resistance (LPR), potentiodynamic polarization and monitoring corrosion potential techniques. Experimental results showed that an increase of the commercial inhibitor concentration up to 500ppm increases the RP value and produces an efficiency of 90 percent. The increase of a test solution temperature at 60°C caused an increase on RP value compared to RP measured at room temperature this suggests adsorption of the inhibitor is promoted by temperature. Plot of c/θ versus inhibitor concentration (c) using different methods showed a straight line with a slope very close to unity, indicating that adsorption of the investigated commercial inhibitor on steel/saturated CO2 solution obeys the Lungmuir adsorption isotherm.