Because the interactions that occur between the workpiece, the abrasive grain, and the nanofluid at the minimum quantity lubrication (MQL) grinding interface are difficult to record instantly, there is still a paucity of direct evidence to reveal the internal mechanism of the carbon group nanoparticles present in the abrasive grains. or workpiece grinding interface.
Considering this problem, Professor Changhe Li’s team from the Department of Mechanical and Automotive Engineering of Qingdao University of Technology, China, used molecular dynamics simulations to study the tribological mechanisms of friction reduction and anti-wear of three types of carbon. class of nanoparticles, namely graphene, diamond, and carbon nanotubes.
Under MQL conditions, this research will reveal the mechanism of lubrication film formation on grinding surfaces. Depending on this, the tribological behavior of the nanoparticles at the interface will be additionally examined.
Direct evidence will be offered to reveal the mechanism of effect of carbon cluster nanoparticles present at the milling interface.
This study can be found in the journal Mechanical Engineering Frontier on April 26thth2023.
In addition, carbon class nanofluids can enhance the MQL’s friction reducing and anti-wear properties. But the mechanism of forming the lubrication film generated by the carbon group nanofluid at the MQL grinding interface is not fully disclosed due to lack of sufficient evidence.
In this study carried out, molecular dynamics simulations were carried out to explore interactions at the abrasive grain or workpiece grinding interface and to reveal the mechanism of lubrication film formation.
Three representative types of carbon cluster nanoparticles, namely, carbon nanotubes, nano-diamonds, and graphene nanosheets, were taken as research targets, and ionic liquid (BMIM)BF4 was used as the basic fluid of the nanofluids.
Initially, the study uncovered the mechanism of lubrication film formation under MQL conditions only with the help of ionic liquids. Based on this, the tribological behavior of the nanoparticles at the milling interface was also examined to demonstrate the tribological mechanism of the carbon nanofluid groups at the milling interface.
Investigation showed that a boundary lubrication film had formed at the grinding interface under MQL conditions through ionic liquid molecules adsorbing groove-like cracks on the wear flat surface of the grains.
Availability of boundary lubrication film takes the effect of reducing friction through reducing the abrasive grain or workpiece contact area. While subjected to MQL nanofluid conditions, the carbon group nanoparticles also enhance the tribological performance of the MQL method benefiting from the equivalent tribological behavior at the milling interface.
The rolling effect of nano-diamond, the rolling and sliding effect of carbon nanotubes, and the interlayer sliding effect of graphene nanosheet have been included in the behavior. Compared to the MQL condition, the tangential grinding forces also decreased by 8.5%, 12.0% and 14.1% under the MQL conditions of carbon nanotubes, diamond and graphene nanofluid.
This offers direct evidence for the mechanism of the effect of carbon group nanoparticles on the abrasive grain or workpiece grinding interface.
Wang, D., et al. (2023) Tribological mechanism of carbon group nanofluids at the milling interface under minimum quantity lubrication based on molecular dynamics simulations. Mechanical Engineering Frontier. https://doi.org/10.1007/s11465-022-0733-z.