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A rapid cooling process is essential to maintain an optimal working temperature in a vehicle, which directly impacts its efficiency. Corrosion is a persistent and inevitable damage in cooling systems that use water-based fluids. The current challenge is to explore water-based fluids that not only exhibit excellent corrosion resistance but also possess superior heat conduction properties to improve vehicle efficiency. This study investigated the incorporation of Graphene Oxide, renowned for its corrosion inhibition properties, into ethylene glycol/water solution to assess its protective efficacy on Al6061 material. A series of analytical methods, including Optical Emission Spectroscopy (OES), pH, conductivity, Fourier-Transform Infrared Spectroscopy (FTIR), and polarization techniques, are used to evaluate the corrosion inhibition performance of graphene oxide at various concentrations and under different ambient temperatures. The results showed a decrease in pH value and conductivity with increasing concentration of graphene oxide. FTIR analysis confirmed the formation of a protective layer on the surface of Al6061. Corrosion rate assessment was performed on Al6061 samples immersed in ethylene glycol/water mixture with graphene oxide concentrations of 0, 0.03%, 0.05%, and 0.10%. There was a significant decrease in corrosion rate with the addition of graphene oxide to the cooling system: at 30°C, the rate decreased to 4.620, 3.308, 2.565, and 1.006 mpy; at 40°C, up to 4,728, 2,541, 1,503, and 1,270 mpy; and at 50°C, up to 5.629, 1.146, 2.947, and 1.441 mpy, corresponding graphene oxide concentrations of 0.03%, 0.05%, and 0.1%, respectively. Experimental data confirmed that graphene oxide effectively reduces the corrosion rate of Al6061 in ethylene glycol/water mixtures. The study concluded that the use of graphene oxide as a corrosion inhibitor markedly improved the resistance and performance of Al6061 in ethylene glycol/water, with graphene oxide contributing to this protective mechanism through the process of physisorption.

This study evaluated Aloe vera extract as a green inhibitor to prevent corrosion in seawater environments. A. vera extract was produced by maceration with methanol-water at room temperature. Electrochemical techniques were used to evaluate the corrosion inhibitor effectiveness of the A. vera extract. The morphology of the corrosion products was analyzed by FE-SEM equipped with EDS and AFM. FT-IR and LCMS characterized the functional and structural groups in this extract. The electrochemical measurements show that A. vera extract could effectively reduce the corrosion of API 5L steel in seawater environments. Inhibition efficiency (IE) increases with increasing concentration. Optimal corrosion inhibition efficiency of around 83.75% (PDP) and 88.60% (EIS) was obtained by adding 300 mg L -1 of extract at 310 K. Furthermore, the higher the concentration of A. vera extract, the greater the activation energy (E a ), with the highest activation energy being 48.24 kJ mol -1 for the concentration of 300 mg L -1 . Conversely, increasing the temperature and exposure duration reduces the corrosion inhibition efficiency (IE) values; the best exposure period was 30 min with 88.34% IE by a concentration of 300 mg L -1 at 300 K. This corrosion inhibition is achieved by the adsorption process of A. vera bioactive on metal surfaces with a mixed inhibitor through a physisorption-chemisorption mechanism. This finding was confirmed by the smoother surface morphology of the steel treated with A. vera extract than without. This unveiling investigation found that A. vera extract has the potential to be an environmentally friendly corrosion inhibitor in the seawater environment., (© 2024. The Author(s).)