Gold-ionic liquid nanofluids with preferably tribological properties and thermal conductivity

Area of Science:

• Materials Science
• Nanotechnology
• Tribology
• Thermal Engineering

Background:

• Ionic liquids (ILs) are explored as advanced lubricants.
• Gold nanoparticles (Au NPs) have potential as lubricant additives.
• Achieving stable nanofluids for practical applications remains a challenge.

Purpose of the Study:

• To fabricate stable gold/ionic liquid nanofluids using a facile one-step method.
• To investigate the tribological properties of these nanofluids.
• To evaluate the thermal conductivity of the stable nanofluids.

Main Methods:

• Fabrication of gold/1-butyl-3-methylimidazolium hexafluorophosphate (Au/[Bmim][PF6]) nanofluids via chemical reduction.
• Characterization using transmission electron microscopy, UV-visible absorption, FTIR, and XPS.
• Tribological testing under load and thermal conductivity measurement using a transient hot wire method.

Main Results:

• Cetyltrimethylammonium bromide (CTABr) stabilized nanofluids exhibited superior thermodynamic stability.
• Stable Au/[Bmim][PF6] nanofluids demonstrated significant friction reduction (up to 13.8%) and anti-wear properties (45.4% reduction in wear volume) compared to pure [Bmim][PF6] under high load (800 N).
• Thermal conductivity increased by 13.1% at 81°C for the highest concentration nanofluid, attributed to micro-convection from Brownian motion of Au NPs.

Conclusions:

• Stable Au/[Bmim][PF6] nanofluids, particularly those stabilized by CTABr, are effective high-performance lubricant additives.
• These nanofluids offer enhanced tribological properties and improved thermal conductivity.
• The findings suggest potential applications in advanced lubrication and high-temperature heat transfer systems.