Capillary Electro-Osmosis Properties of Water Lubricants Under a Steel-on-Steel Sliding Interface

The process of penetration of lubricants into the frictional interface in steel machining such as turning and milling is not well revealed, which has thus compromised their machining performance. In this paper, the penetration characteristics of deionized water (Di-water) containing different electro-osmosis additives were investigated using a steel-on-steel friction pair. The worn surface lubricated with water solutions were examined using advanced surface analysis techniques. The results indicate that water lubricants were electrically driven to the frictional interface for lubrication. The addition of positive electro-osmosis additives helped promote the penetration of water solutions, thus resulting in the formation of a thick lubricating film of iron oxide at the sliding surface. This reduced abrasion damage significantly, therefore producing a lower coefficient of friction (COF) and wear loss in comparison with pure water.