Design and Evaluation the Anti-Wear Property of Inorganic Fullerene Tungsten Disulfide as Additive in PAO6 Oil

• Main Authors: Wenting Chen, Kunyapat Thummavichai, Xiaorong Chen, Guangsheng Liu, Xuefeng Lv, Linyi Zhang, Ding Chen, Santosh Kr. Tiwari, Nannan Wang, Yanqiu Zhu
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Crystals
• Subjects: inorganic fullerene; disulfide tungsten; additive; high performance lubricating oil; PAO6; anti-wear
• Online Access: https://www.mdpi.com/2073-4352/11/5/570

Inorganic fullerene-like tungsten disulfide particles have been proved to have good anti-friction and anti-wear properties as lubricating materials. As far as we know, however, when it is used as a lubricant additive, its behavior and action mechanism in the friction process are rarely studied. Herein, IF–WS₂ particles were synthesized by a Chemical Vapor Deposition (CVD) method. The effect of IF–WS₂ particle concentrations in the PAO6 oil on the tribological behaviors was investigated with a four-ball wear machine at both 75 and 100 °C. Additionally, the analyzed morphology and composition of nanomaterials and worn surfaces were analyzed by Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The friction behavior in actual working conditions was studied by a wear testing machine. The experimental results show that compared with the original PAO6 oil, at a dispersion of 0.25 wt% in PAO6 oil, the IF–WS₂ particles showed the best performance in terms of coefficient of friction, wear scar diameter and wear mass, which significantly reduced by 27%, 43% and 87%, respectively. At the same time, in the process of friction, it was found that IF–WS₂ particles accumulated in the depressions to fill the scratches, and adsorption films and chemical films, including FeS₂, WS₂ and WO₃, were formed on the worn surfaces to avoid the direct contact among the friction pairs more effectively, resulting in the improved anti-wear performances. Additionally, the addition of IF–WS₂ particles effectively delayed the rise of lubricating oil temperature. In addition, dispersant span 80 can effectively improve the dispersion and stability of IF–WS₂ in PAO6. This work provides us for understanding the effective lubrication mechanism of IF–WS₂ particles in more detail and having a new acknowledge of the comprehensive performance of IF–WS₂/PAO6 oil.