The effect of particle size on the lubricating properties of colloidal polystyrene used as water based lubrication additive

A series of colloidal polystyrene (PSt) with different average diameters (1 10-368 nm) were prepared. Four-ball test results show that the load carryin g capability of the relevant water based fluid is proportional to the avera ge diameter of the PSt. However, there is no obvious effect of particle siz e on wear reduction with PSt. It is also found that sulfur in the emulsifie r makes no contribution to the EP property of the fluid through comparative tests. Based on scan electron microscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy examinations of the worn surfaces, it is s upposed that the load carrying and anti-wear capabilities of the fluids wit h PSt are associated with the penetration of PSt particles into the rubbing surfaces during sliding. (C) 2001 Msevier Science B.V. All rights reserved .