Study on the corrosion inhibition and lubrication behavior of magnesium borate modified with lauryl glycol on cylinder liner materials in methanol engines

In order to solve the problem of acidic corrosion and wear of cylinder liner-piston rings of methanol-fueled marine engines, the present study innovatively synthesized lauryl glycol modified magnesium borate (L-MgB₂O₄) by plasma-assisted ball milling. The covalent B–O–C bonding mechanism not only achieves nanoscale (200–300 nm) refinement, but also ensures pH-responsive release of borate in acidic environments compared with conventional non-covalent modification methods. Conformational characterization (scanning electron microscopy) confirmed the suppression of agglomeration and improved dispersion, while FTIR analysis verified the covalent grafting of lauryl glycol. Electrochemical tests performed in simulated methanol combustion solution showed that the corrosion inhibition efficiency of L-MgB₂O₄ was concentration-dependent, reaching 89.3% at 0.07 wt% L-MgB₂O₄, which was attributed to the synergistic increase in pH and surface passivation. Secondly, the deposition of additives observed on the surface of corroded specimens also had a protective effect on the specimens. Tribological evaluations conducted in accordance with ASTM DG133-05 showed that 0.05 wt% L-MgB₂O₄ reduced the coefficient of friction by 14% and wear volume by 49% compared to the base oils, which is superior to conventional additives. Three-dimensional profiling shows a concentration of the wear peak distribution, which effectively improves the contact condition. L-MgB₂O₄ acts as a lubricant additive through physical adsorption (nanoscale refinement) and as a corrosion inhibitor through borate release. It provides a new solution for improving the durability of methanol engine components. This green, solvent-free synthesis meets International Maritime Organization (IMO) emission reduction targets and bridges the gap between corrosion inhibition and lubrication enhancement in alternative fuel systems.