An Oil-Based Lubrication System Based on Nanoparticular TiO2 with Superior Friction and Wear Properties

Abstract

We evaluated the performance of five different commercially available nanoparticle classes as additives for an oil-based lubrication system. While the silicon dioxide particles Aerosil Ò 300, RY300, and R972V tended to increase wear and friction in our 100Cr6 versus cast iron disc-disc contact, Aeroxide Ò P 25 and especially T 805 TiO 2 nanoparticles showed superior anti-wear and antifriction properties. The underlying tribological mechanism was investigated with optical microscopy, helium ion microscopy, and X-ray photoelectron spectroscopy. Subsequently, we formulated a stable lubrication system based on the best performing T 805 particles. Here, the base oil is a highly purified paraffin oil which was supplemented with 1 wt% T 805 TiO 2 particles, 1 wt% Estisol Ò 242 or 1 wt% oleic acid, 0.15 wt% oleylamine, and 0.15 wt% Pluronic Ò RPE 2520. Superior lubrication and anti-wear properties of this formulation were demonstrated in 4-h test runs with a normal force of F N = 2.5 kN and a sliding velocity of 0.15 m/s in our disc-disc contact. Wear was significantly reduced along with a nearly 12-fold reduction in the friction coefficient, compared to the base oil ðl fto base ¼ 0:155 vs: l fto T805 % 0:01Þ. Using 100Cr6 disc-ball contacts, we additionally analyzed the properties of our lubrication system in the border friction regime under higher loads (F N = 0.5 kN) in 2-h runs. In particular, on the discs with lower engagement ratio, chemo-tribological protective layers were built, which protected the parts very well against wear.

Tribological Properties of Aluminum Nanoparticles as Additives in an Aqueous Glycerol Solution

“…The combined effects of the tribo-film and the ball-bearing of nanoparticles prevent the development of wear tracks. The same results have been reported by Bogunovic et al [26] and Zhang et al [27]. The COF curves of friction tests of 120 min are displayed in Figure 9; the COF was the highest for the lubricant with 10 wt % water content of glycerol among the three experiments.…”

Dispersion of Nanoparticles in Lubricating Oil: A Critical Review

“…As nanolubricants require a long time to become stable, methods have been reported to examine dispersion in time. The widely used method is visual inspection [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The lubricant dispersed with nanoparticles is visually different compared to a lubricant.…”

“…In early research (before 2005), the common method used to study the effects of nanoparticles in lubricant was to disperse these nanoparticles using dispersants [47,56,64,68,79,102,105]. The dispersants used including Aliquat 336 [68], Estisol 242 [12], oleic acid [12], sorbitol monostearate [47,105], and several others. These dispersants were mixed with the nanoparticles and the lubricant oil to create a stable dispersion.…”

“…These dispersants were mixed with the nanoparticles and the lubricant oil to create a stable dispersion. In some cases, multiple types of dispersants were used simultaneously [12].…”

Preparation and tribological properties of the N‐containing heterocyclic borate esters and Cu microparticles as lubricant additives in base oil

“…Cu nanoparticles have been desired for a good alternative to traditional lubricant additives because of the significant tribological performance and display good anti-friction and anti-wear properties and good self-healing functions to the worn surface. 20,21,29 Factors, such as the concentration of nanoparticles, sliding speed, applied load and 20,[30][31][32][33][34][35] how to affect the performance of the lubricant oil, have been also considered. Zhang et al 21 found that the concentration of Cu nanoparticles has a remarkable effect on the tribological properties of base oil.…”