Organic-modified ZnS nanoparticles as a high-performance lubricant additive.

Area of Science:

• Materials Science
• Tribology
• Nanotechnology

Background:

• Lubricants are critical for reducing wear in machinery and transportation.
• Antiwear additives enhance lubricant performance by minimizing friction-induced material loss.
• There is a need for oil-miscible and optically transparent nanoparticles as advanced lubricant additives.

Purpose of the Study:

• To synthesize and evaluate dodecanethiol-modified zinc sulfide nanoparticles (ZnS NPs) as antiwear additives.
• To assess the tribological performance and oil transparency of ZnS NPs in a polyalphaolefin (PAO) base oil.
• To compare the effectiveness of ZnS NPs against commercial antiwear additives like zinc dialkyldithiophosphate (ZDDP).

Main Methods:

• Synthesis of 4 nm dodecanethiol-modified ZnS nanoparticles.
• Preparation of stable, transparent suspensions of ZnS NPs in PAO lubricating oil.
• Tribological testing to evaluate friction and wear reduction, including surface characterization.

Main Results:

• ZnS NPs formed transparent, long-term stable suspensions in PAO oil.
• 0.5-1.0 wt% ZnS NP concentrations demonstrated excellent friction and wear protection.
• Achieved 98% wear reduction compared to neat PAO4 and 40-70% greater reduction than ZDDP.
• Formation of a self-healing polycrystalline ZnS-derived tribofilm (<250 nm) was observed.

Conclusions:

• Dodecanethiol-modified ZnS NPs are effective, transparent antiwear additives for lubricants.
• ZnS NPs exhibit superior tribological performance compared to conventional ZDDP.
• These nanoparticles show significant potential for broad transportation and industrial applications.