High temperature tribological properties of surface modified potassium borate as additives for marine cylinder lubricating oil

Abstract

Lauric acid sodium salt and cetyltrimethyl ammonium bromide as compound modifiers, surface modified potassium borate lubricant additives were prepared by plasma assisted ball milling as well as characterized and analyzed by scanning electron microscope (SEM), infrared spectrometer (FT-IR) and thermal analyzer (DSC-TG). Meanwhile, the high temperature tribological properties in low alkali marine cylinder oil were studied, and the antifriction self-repair mechanism was discussed. The results indicate that the potassium borate powder and modifiers are micro-zone melted and rapidly refined by the coupling effect of plasma thermal effect and mechanical milling of steel balls during plasma assisted ball milling for 10 h, and the average particle size of the primary particles is 100-300 nm. As the chemical action of ion pair in modifiers, the potassium borate powder adsorbs and chemically bonds with —CH2 and —CH3 organic molecular groups, which realize the lipophilic modification and a good dispersity in FEOCY 54 low alkali marine cylinder oil of the power. In the process of friction, potassium borate particles continuously adsorb and deposit on the friction surface by the effect of electric charge, and the rolling lubrication and anti-wear deposition films are formed in the metal contact area. At the same time, the friction surface reacts with potassium borate powder to produce Fe2O3, Fe3O4 and B2O3 boundary lubricating films that have the effect of antifriction and anti-wear, which greatly improves the high temperature tribological properties of marine cylinder oil.

Keywords

• plasma assisted ball milling
• potassium borate
• lubricant additive
• marine cylinder oil
• high temperature tribological property