Effect of surfactant on tribological performance and tribochemistry of boric acid based colloidal lubricants

Abstract

This study demonstrated that surfactants can significantly improve the dispersion stability of milled boric acid particles over a broad range of operating temperatures. The tribological performance of boric acid and surfactant [sorbitan trioleate (STOMO)] mixed in the base oil was investigated under cylinder-on-plate line contact set-up using a reciprocating tribological test rig. Several characterisation techniques were used to understand particle distribution and size and composition of tribofilms that resulted from sliding contact. The results showed that surfactant prevented agglomeration of boric acid particles after the milling process and thus, provided good dispersion stability at elevated temperatures. The addition of surfactant in the base oil decreased the friction coefficients by 58 and 42% respectively, and reduced the wear scar diameter by 48 and 34% respectively, as compared to the base oil and fully formulated oil. In addition, the presence of a boron rich boundary film resulting from decomposition of boric acid compounds were detected by XPS and Auger in the wear track inside the wear tracks.

Investigation of Tribological Properties of Graphene Nanoplatelets in Synthetic Oil

“…Anti-wear (AW) and extreme pressure (EP) additives are essential in several frictional conditions [4]. However, the conventional AW and EP additives containing harmful compounds such as sulfur, chlorine, and phosphorus cause a negative effect on the environment [5]. Therefore, nanoparticles are considered a promising new class of lubricant additives currently being investigated by researchers.…”

A simple route to suspend boric acid in non-polar media

“…According to the available literature, limited studies have been addressed on stable suspension duration [8][9][10][11]. Researchers have also studied to disperse and suspend boric acid particles of different sizes in different media [12][13][14]. However, these studies did not focus on how long boric acid particles were suspended in the corresponding media.…”

“…Boric acid also forms tribofilm on sliding surfaces and prevents excessive wear on these surfaces by reducing friction [12]. In addition, boric acid acts as a third body between two contacting surfaces providing hybrid lubrication (oil + particle lubrication) when it is added to engine oil [13,19]. However, one of the biggest disadvantages of using a nanoparticle as a lubricant additive is that the particulate additives are agglomerated and collapsed in engine oils.…”

Lubrication effectiveness investigation on the friendly capped MoS2 nanoparticles

“…Generally, oil‐soluble surfactants were applied to modify the bare nanoparticle to prevent aggregation due to its high surface energy, such as the triglycerides, lecithin, γ‐aminopropyltrimethoxy silane and polyisobutyleneamine succinimide (PIBS) . However, the influence of surfactants on other performances of formulated oil remains unknown.…”