Penetration Properties of Lubricants Containing Different Electroosmotic Additives at Diamond/Aluminum and Diamond/Nylon Interfaces as Related to Triboemission

Abstract

The penetration behavior of lubricants may be related to triboemission. To understand this relationship, first, the effects of the electroosmotic additives 3-[3-(cholamidopropyl)dimethylammo]-1-propanesulfonate (CHAPS) and cetyltrimethylammonium bromide (CTAB) on the penetration of lubricants were discussed through experiments that involved cutting aluminum and nylon with a diamond tool. It was found that CHAPS can reduce cutting force and surface roughness compared with water only, so the workpiece showed good cutting performance, while CTAB exhibited the opposite behavior. Moreover, with the increase in cutting depth and cutting velocity, this effect became more obvious. On this basis, the electroosmotic mechanisms of CHAPS and CTAB were analyzed, and it was concluded that there may be an electric field (a negative one) from the open end to the closed end inside the capillary at the friction interface. Finally, a triboemission test was used to detect particle emission in the cutting area. The result then showed that the particles were mainly negative particles, and their intensity strengthened with the increase of cutting depth and cutting velocity. Therefore, a relationship between triboemission and electroosmosis of lubricants was established. Triboemission was inferred to be the primary reason for the negative electric field in the capillary, which causes electroosmosis of lubricants containing CHAPS or CTAB.