Abstract: Four typical corrosion inhibitors—N-acylsarcosine, phosphate ester amine salt, alkenyl succinic semi- ester, and imidazoline alkenyl succinate—were systematically investigated regarding their corrosion inhibition performance and effects on the high-temperature oxidative stability and lubrication properties of lubricatingoils.Experimental results demonstrated that the highly polar carboxamide bifunctional N-acylsarcosine-based corrosioninhibitor FY1 and ionic phosphate ester amine salt corrosioninhibitor FY2 with strong polarity exhibited significant efficacy in improving both salt spray corrosion resistance and seawater corrosion resistance of lubricating oils. However, lubricatingoils formulated with FY2 showed inferior anti-friction and anti-wear performance and high-temperature oxidative stability.Molecular dynamics simulations were employed to study the correlation between adsorption behavior of corrosion inhibitors and their corrosion resistance. The results revealed that lower adsorption energy of inhibitors correlates with superior corrosion resistance. For practical applications, N-acylsarcosine-based corrosion inhibitors can be preferentially selected to effectively address harsh operating conditions while enhancing the corrosion resistance of lubricating oils.

Key words: corrosion inhibitor, salt spray corrosion resistance, lubricating oil, extreme pressure and anti-wear properties, oxidative stability