Molecular dynamics simulation of effects of nanoparticles on frictional heating and tribological properties at various temperatures

Abstract

The temperature of a friction pair exerts considerable influence on the tribological behavior of a system. In two cases, one with and the other without Cu (copper) nanoparticles, the temperature increase in friction pairs caused by frictional heating and its tribological properties at various temperatures are studied by using the molecular dynamics approach. The results show that temperature distribution and surface abrasion are significantly improved by the presence of Cu nanoparticles. This is one of the reasons for the improvements in tribological properties achieved in the presence of nanoparticles. The temperature and range of influence of frictional heating for the model without nanoparticles are significantly increased with the increase in the sliding velocity; however, in the model with nanoparticles, the temperature gradient is confined to the area near the Cu film. With an increase in the temperature of the friction pair, the improvement in anti-wear properties associated with the presence of Cu nanoparticles becomes more significant.

Origin of the tribofilm from MoS2 nanoparticle oil additives: Dependence of oil film thickness on particle aggregation in rolling point contact

“…This is contrast to the results in Figs. 4 and 5, which reveals that the addition of 0.1 wt% MoS 2 nanoparticles in PAO4 significantly improved the oil film thickness 4 and 8 suggest that the operating velocity also influences the increase in oil film thickness, even for the same oil sample (0.1 wt% MoS 2 nanoparticles). An appropriate velocity should be applied to achieve the increase in oil film thickness.…”

“…Lubricant material design for modern engines must consider low oil viscosity, which results in low oil-film thickness and reduced energy consumption in the hydrodynamic lubrication regime. However, this is associated with direct asperity contact in both boundary lubrication and mixed lubrication [3,4].…”

Mechanochemical reactions of GaN-Al2O3 interface at the nanoasperity contact: Roles of crystallographic polarity and ambient humidity

“…Due to the randomly repeated action of multiple abrasive particles and uncontrollable external mechanical interaction, the actual material removal process can hardly be monitored and quantitatively characterized in realtime [11]. Different from the internal property of material, the tribological performance as a system response may change with the environmental parameters (e.g., relative humidity (RH) and temperature), surface properties (e.g., hardness, chemical activity, and atomic structure), and processing parameters (e.g., applied load/pressure, velocity, and processing time) [12][13][14][15][16][17][18]. Hence, the well-designed approach is desired to obtain the mechanistic knowledge of the occurrence of mechanically-stimulated chemical reactions between the abrasive nanoparticle and the GaN substrate in the single-asperity contact with precisely controlled contact pressure/area, velocity, reactant concentration, and reaction time.…”

Elementary, Atomic-Level Friction Processes in Systems with Metallic Inclusions—Systematic Simulations for a Wide Range of Local Pressures

“…The applied MD simulations demonstrated the formation of a sliding layer after the disintegration of Cu nanoparticles. A very recent paper (2020, [ 14 ]) also reports a positive impact of atoms from Cu nanoparticles on the frictional properties of an Fe-Fe sliding system at elevated temperatures and under high loads as well as the profiting tendency of lowering the local temperature during friction. These MD simulations were based on the method of quantum semi-empirical embedded atom (EAM) potentials [ 15 , 16 ].…”