Abstract:
The electroosmosis effect is a complement to the theory of the traditional capillary penetration of cutting fluid. In this study, based on the electric double layer (EDL) characteristics at friction material/solution interfaces, the influences of additives and their concentrations on capillary electroosmosis were investigated, and a water-based cutting-fluid formulation with consideration to the electroosmosis effect was developed. The lubrication performance levels of cutting fluids were investigated by a four-ball tribometer. The results show that the EDL is compressed with increasing ionic concentration, which suppresses the electroosmotic flow (EOF). The specific adsorption of OH- ions or the dissociation of surface groups is promoted as pH rises, increasing the absolute zeta potential and EOF. The polyethylene glycol (PEG) additive adsorbed to the friction material surface can keep the shear plane away from the solid surface, reducing the absolute zeta potential and EOF. The electroosmotic performance of cutting fluid can be improved by compounding additives with different electroosmotic performance functions. Furthermore, electroosmotic regulators can adjust the zeta potential by the electrostatic adsorption mechanism, affecting the penetration performance of cutting fluid in the capillary zone at the friction interface. The improvement in the tribological performance of cutting fluid developed with consideration given to the electroosmosis effect is attributed to the enhancement of the penetration ability of the cutting fluid and the formation of more abundant amounts of lubricating film at the interface.
摘要:
电渗效应是对切削液传统毛细管渗透理论的补充。在这项研究中,基于摩擦材料/溶液界面处的双电层(EDL)特性,研究了添加剂及其浓度对毛细管电渗的影响,并开发了一种考虑电渗效应的水基切削液配方。用四球摩擦计研究了切削液的润滑性能水平。结果表明,EDL随着离子浓度的增加而压缩,抑制电渗流(EOF)。随着pH值的升高,促进OH-离子的特异性吸附或表面基团的解离,增加绝对zeta电位和EOF。吸附在摩擦材料表面的聚乙二醇(PEG)添加剂可以使剪切面远离固体表面,降低绝对zeta电位和EOF。复合具有不同电渗性能功能的添加剂可以提高切削液的电渗性能。此外,电渗调节剂可以通过静电吸附机制调节ζ电位,影响切削液在摩擦界面处毛细管区的渗透性能。考虑到电渗效应而开发的切削液的摩擦学性能的改善归因于切削液的渗透能力的增强和在界面处形成更大量的润滑膜。