Insights into the influence of additives on the thermal gradient induced migration of lubricant

Abstract

Thermo‐capillary migration is a phenomenon that the thermal gradients will drive a liquid to flow from warm to cold regions. It is of great importance to prevent the lubricant migration on rubbing surfaces in the cases where the amount of lubricant is limited. In this paper, four different lubricant additives are incorporated into one base oil, and the effects of additives on the migration behaviour and surface tension coefficient are investigated. The functional mechanisms of additives are discussed. The experimental results demonstrate that the additives have remarkable influences on the migration performance of lubricant. The migration behaviour shows the relation to not only the surface tension coefficient, but also the actions between the additive and substrate. This should be considered in the designing process of an anti‐migration lubricant. Copyright © 2016 John Wiley & Sons, Ltd.

The thermocapillary migration on rough surfaces

“…By solving the balance of these 2 forces, a theoretical expression for the migration velocity can be achieved . In practice, utilisation of specialty lubricants or lubricant additives provides an effective way to either mitigate or impede the thermocapillary migration. Surface energy barriers can also be generated via painting low‐surface energy fluorocarbon compounds around the rubbing or contacting areas to confine the lubricant movement at the desired locations and limit its migration …”

The thermal capillary migration properties and controlling technique of ferrofluids

“…Our previous research has demonstrated that adding T161 into a base oil will increase the surface tension and accelerate the migration of lubricant. 30 Therefore, on one hand, when the carrier liquid mixed with T161, the surface tension is increased (Table 3), which promotes the migration behavior and resulting in a longer migration distance than the pure one. On the other hand, for the FF used in this study, this dispersant is indispensable since it is chiefly used for improving the dispersion performance of the nanoparticles in the carrier liquid and enhancing the stability of FF.…”