Liquid metal/ionic liquid lubricants: rational design and tribological performance evaluation

Abstract

To improve the performance of lubricants, a liquid metal/ionic liquid 1-hexyl-3-methylimidazole hexafluorophosphate (LM/IL) additive was prepared in this study using a simple ultrasonic dispersion method. The extreme pressure performance, anti-wear, and friction reduction properties of LM/IL were examined using a four-ball tribo-meter. After incorporating 0.2 wt% LM into IL, the P_B value of LM/IL increased by 46.9% from 1962 N to 2884 N. The LM/IL also exhibited superior anti-wear and friction reduction properties at 392 N. Results of the first principles calculation and experimental tests indicate that the friction induced chemical reactions to form a boundary lubrication film that significantly enhanced the tribological properties of the lubricant.