Significantly Affected Lubrication Behavior of Silicone Oil Lubricated Si₃N₄/Glass Contact after Cleaning with Different Solvents

Abstract

Conventional methyl silicone oils have poor lubricating properties in boundary lubrication regions, particularly for ceramic/oxide point contact lubrication. In this study, the residues of various organic solvents on the surfaces of Si 3 N 4 spheres/glass disks were used to determine their effect on the lubricating properties of silicone oil 200. The minute ethanol residues significantly enhanced the antifriction and antiwear properties of silicone oil. Compared to the blank sample, the coefficient of friction (COF) and wear volume of silicone oil 200 with the residual ethanol friction pair were reduced by >40% and >98%, respectively. Being immiscible with silicone oil, the minute ethanol residues also removed impurities from the glass surface and maintained a clean interface, thus effectively blocking direct interactions between the friction pair interfaces. In addition, the residual ethanol reduced the atomic force microscope probe-to-glass surface adhesive force in the silicone oil 200 environment, thus allowing it to maintain low COF and wear rates over a broader range of speeds, loads, and times. In contrast to previous work, this study is the first to effectively regulate the lubrication properties of silicone oil using a residual organic solvent. The findings further verified that the adsorption of vapor molecules can significantly alter the surface forces between interfaces. Thus, adjusting the adhesion force through trace amounts of organic solvent residues may provide novel research inputs, thereby guiding the expansion and scope of silicone oil lubrication applications.

Impact of Water Content on the Superlubricity of Ethylene Glycol Solutions

“…In this experiment, 100 µL of a 50 wt.% EG solution was initially applied and operated for 1800 s under the conditions of 3 N and 94.2 mm/s, ensuring complete running-in and the attainment of a superlubricant state (the first stage is shown in Figure 6a). Subsequently, while keeping the contact area of the friction pair unchanged, the worn area was cleaned with absolute ethanol to remove abrasive particles [31] and dried with N 2 to eliminate any residual organic solvent [30]. In the second stage, 100 µL of an EG solution with varying concentrations (10, 50, and 90 wt.%) was introduced into the contact area individually, and the operation continued for 1800 s under the same conditions.…”

“…For the experiments, the Dow EG solution, with a purity exceeding 99.9%, was procured from Shanghai Kangmiao Trading Co., Ltd. (Shanghai, Beijing). Additionally, highpurity solvents, including petroleum ether, acetone, and absolute ethanol, were obtained from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, Beijing), with purities surpassing 99%, conforming to international standards [30]. The ultrapure water (UP) utilized in the study exhibited a conductivity of 18.2 MΩ•cm and a total organic carbon content of less than 2 ppb [31].…”

Fortified Lubricating Response to Sustainable PEG System from Protic Ionic Liquid and Their Strong Hydrogen Bonding Network

“…Therefore, the mass results of metal surfaces lubricated by PEG200 (Figure 5) showed that characteristic positive and negative ion fragments were observed on the surfaces, where C 2 H 5 + , FeOH + , OH − , and C 2 HO − were located at m/z 73.01, 29.04, 17.00, and 41.00 in the mass spectra, respectively. 52 The distribution of ionic fragments on the metal surface can be visualized by the mapping spectrum; here, the concentration of ionic fragments is higher concerning the brighter areas under the reference of the ruler. 53,54 Thus, it is quite reasonable to see that OH − and C 2 H 5 + fragments are the brightest in the PEG200 (Figure 5) lubrication system that contains a large number of hydroxyl and polar oxygens, which tend to polarity adsorb at the metal surface under the shearing action of mechanical force.…”