Capillary electroosmosis properties of water lubricants with different electroosmotic additives under a steel-on-steel sliding interface

Abstract

The process of lubricant penetration into frictional interfaces has not been fully established, hence compromising their tribological performance. In this study, the penetration characteristics of deionized water (DI water) containing an electroosmotic suppressant (cetyltrimethylammonium bromide (CTAB)) and an electroosmotic promoter (sodium lauriminodipropionate (SLI)), were investigated using steel-on-steel friction pairs. The results indicated that the lubricant with electroosmotic promoter reduced the coefficient of friction and wear scar diameter, whereas that with an electroosmotic suppressant exhibited an opposite behavior compared with DI water. The addition of SLI promoted the penetration of the DI water solution, thus resulting in the formation of a thick lubricating film of iron oxide at the sliding surface. This effectively reduced the abrasion damage, leading to a lower coefficient of friction and wear loss.

A comparison of wear between unidirectional and reciprocating sliding motions under different applied loads and lubricants

“…The different morphology of the wear tracks and ball surface indicates that the wear mechanism under the two sliding motions is different. According to Feng et al, a hard iron oxide layer is formed on the worn surface when sliding under deionized water [38], which is also proved by the Raman mapping results in figure 8. The hard iron oxide layer (Fe 2 O 3 ) can protect the disk from being worn, thus decreasing the wear rate of the disk under USM.…”

“…In terms of USM, the worn area of the PTFE substrate is relatively smooth, which is accompanied by the production of a large amount of parallel slight ploughings. The parallel slight plowings are attributed to the discrete transfer layer [38]. Moreover, the discrete transfer layer could also decrease the COF and wear rate under USM.…”

Effects of the Electric Double Layer Characteristic and Electroosmotic Regulation on the Tribological Performance of Water-Based Cutting Fluids

“…To ensure the considerable electroosmotic performance of the compound cutting fluid and taking into account the amount of general EP additive, the concentration of MOA-3P was set at 0.75 wt% in preparing the water-based cutting fluid (named WCF). To further improve the electroosmotic performance, electroosmotic regulators are often added to the cutting fluid [16,27]. The electroosmotic regulation characteristic of cutting fluid with more complex components is still unclear, which limits the application of the electroosmosis effect in tribology.…”

“…Zhao et al [19] and Brown et al [20] also indicated that the absolute value of the zeta potential decreased with increased ionic strength, which was due to the compression of the EDL by high ionic strength to reduce the charge density in the EDL. Additionally, ionic surfactants adsorbed to charged surfaces by electrostatic or van der Waals forces could significantly affect the zeta potential and have been commonly used to regulate EOF [21][22][23][24][25][26][27]. At present, there is still little research on zeta potentials at friction material/cutting-fluid interfaces, and the influences of cutting-fluid components on zeta potential and EOF need to be further revealed.…”

A review of advances in tribology in 2020–2021

“…Guo et al [25] achieved low-friction coefficients (0.01-0.03) by employing self-mated ceramics, self-mated cemented carbide, and cemented carbide/ceramic under water lubrication. Feng et al [26] found that the deionized water (DI water) containing an electroosmotic promoter (sodium lauriminodipropionate (SLI)) reduced the coefficient of friction and wear scar diameter, whereas, that with an electroosmotic suppressant (cetyltrimethylammonium bromide (CTAB)), exhibited an opposite behavior. Ji et al [27] reported that glyceryl monostearate (GMS)-filled microcapsules largely improved the tribological properties of drilling mud.…”