Enhancing tribological properties of lubricated contacts via synergistic interactions of green silica nanoparticles and ZDDP

• Published in: Tribology international Vol. 197; p. 109829
• Main Authors: Syed, Junaid, Hakkim, N. Lukkumanul, Nebhani, Leena, Gosvami, Nitya Nand
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2024
• Subjects: Friction & Wear; Hybrid nano-lubricants; Silica nanoparticles; Tribofilms; ZDDP; Silica nanoparticles; Friction & Wear; Hybrid nano-lubricants; Tribofilms; ZDDP
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2024.109829

Zinc dialkyldithiophosphate (ZDDP) anti-wear lubricant additive contributes to significant harmful emissions and its replacement has become a priority. In this study, green silica nanoparticles were synthesized and optimized for concentration to serve as hybrid additives alongside ZDDP in lubricants, aiming to mitigate environmental concerns. A combination of 0.5 wt% silica nanoparticles, 0.5 wt% oleic acid (OA), and 0.75 wt% ZDDP demonstrated notable improvements, reducing ZDDP usage by ∼25 % while achieving significant tribological enhancements. At room temperature, coefficient of friction (COF) was reduced by ∼60 %, and wear was reduced by ∼70 %, while at 100 °C, COF was reduced by ∼80 %, and wear was reduced by ∼96 %. Advanced characterization techniques such as FESEM with EDS mappings, EPMA, and TOF-SIMS were employed to elucidate the underlying mechanisms for observed reduction in friction and wear. •A combination of silica nanoparticles and ZDDP is explored as hybrid additive to PAO4 oil.•Conventional ZDDP addition is reduced by 25 % in hybrid additive containing base oil.•Friction reduction of ∼ 60 %, and wear reduction of ∼ 70 % at room temperature using hybrid additive.•Friction reduction of ∼ 80 %, and wear reduction of ∼ 96 % at 100 °C using hybrid additive.•Plausible mechanisms of surface protection using the hybrid additive are proposed.