Superlow friction and diffusion behaviors of a steel-related system in the presence of nano lubricant additive in PFPE oil

Abstract

The lubrication performances of diamond like carbon (DLC) films were investigated by a ball-on-disc tribometer under perfluoropolyether (PFPE) oil lubrications. The influence of nano lubricant additives in PFPE oil on the tribological properties of DLC films was evaluated. The experimental results show that the solid-liquid synergy lubrication is beneficial to improve the tribological properties of the steel-related friction system and the tribological properties of the friction pair are significantly influenced by lubrication modes and the types and contents of nano lubricant additives under PFPE oil lubrication. The friction system exhibits super low friction behaviors under PFPE oil with nano MoS₂ lubricant additive lubrication due to the excellent compatibility of nano MoS₂ additives with PFPE oil. Coefficient of friction (CoF) of the friction system is as super low as 0.02 under PFPE oil with 0.2 wt.% nano MoS₂ additive lubrication. Superlow friction mechanism is attributed to the pointlike contact of nano MoS₂ additive as soft phase and the excellent diffusion behaviors of nano MoS₂ additives in PFPE oil. The potential usefulness of nano MoS₂ particles as the lubricant additives in PFPE oil for the steel/DLC films has been demonstrated.

Keywords:

• Solid-liquid synergy lubrication
• PFPE oil
• nano lubricant additive
• diffusion
• superlow friction

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The present research is financially supported by the National Natural Science Foundation of China [Nos. 51675409 and 51464020] and the Fundamental Research Funds for the Central Universities [xjj2017163] and the key project of Shaanxi province Science and Technology Department [2017ZDXM-GY-115] and Natural Science Foundation of Jiangxi [20161BAB206164].