Study On Tribological Properties Of Aqueous Solutions With Cocamide Polyoxyethylene And Borate

With the shortage of oil resources and the people’s attention to environmental protection, green water-based lubricating fluid has received more and more attention. However, due to its low viscosity, poor film-forming properties, corrosion to metal and other disadvantages of pure water, water-soluble additives of specific functions are needed to be added to modify the tribological properties of water. In the present research, cocamide polyoxyethylene (CPOE) and triethanolamine borate (BN) are selected as basic lubricant additives and their synergetic tribogical properties of aqueous solutions are studied briefly.Firstly, film-forming properties of CPOE and CPOE-BN aqueous solutions are analyzed by NGY-6nanoscale film thickness measuring gauge. Concentration, load and line speed as the major factors are investigated respectively. The results show that both aqueous solutions have better film-forming abilities over water at concentration of1%. The lubricating film is relatively stable and has a certain carrying capacity at the same time. The film thickness gradually decreases with the increase of load, while it increases with the line speed within a certain range. When the line speed reaches to530mm/s, the film thickness maintain substantially about20nm, and tribosysttem is mainly under mixed lubrication.Secondly, the rheological properties of two aqueous solutions are studied by the help of rotational rheometer. Newtonian behavior and dynamic viscosity are mainly taken into consideration. The test results show that the two aqueous solutions exhibite non-Newtonian fluid properties at high temperatures and high concentrations. The higher the concentration, the greater the viscosity is. The addition of BN in CPOE aqueous solutions can significantly reduce the viscosity of the aqueous solution, which can explain the synergistic effect of CPOE and BN on friction reducing partly.Thirdly, friction and wear properties of two aqueous solutions are studied by MRS-10A four-ball tester. Anti-friction and anti-wear properties, stability performances extreme pressure are taken into consideration. The3D surface topography of the ball wear scar is analyzed by3D surface topography instrument. The components of chemical elements on the surface of wear scar are analyzed by X-ray photoelectron spectroscopy. Results show that both solutions have a low and relatively stable friction coefficient. Friction coefficient is lower by the mixture of CPOE and BN than the single CPOE, so as the wear rate at a high load. In addition, the added BN can significantly improve the extreme pressure properties. For3%CPOE and CPOE-BN aqueous solutions, the maximum non-seizure load (PB) of the former is784N, while the latter reaches883N, with a value of99N greater than the former. The mechanism of friction-reducting and anti-wear of CPOE-BN is primarily the result of chemical reactions film and chemical adsorption film working together.Studies have shown that CPOE and BN have a good synergistic effect on lubricating. They can be used in industry with a good prospect as green water-based lubricants.