Al-Doped Ga-Based Liquid Metal: Modification Strategy and Controllable High-Temperature Lubricity through Frictional Interface Regulation

Abstract

Ga-based liquid metal (GLM) may be a potential heat-transfer material in many industries such as electronic devices and nuclear reactors, and thus, improving its lubricity is conducive to solving the friction and corrosion problems of the motion pairs served in the GLM medium. This paper proposes a modification strategy based on the conventional and large-scale mechanical milling to prepare Al-doped GLM successfully and regulates the GLM lubricity through controlling the frictional interface properties. It is found that at room temperature (∼20 °C), the Al element in the Al-doped GLM medium has a stronger adsorption capacity on the T91 surface, so the Al-rich film is formed on the frictional interfaces and reduces the wear of the T91 disk effectively compared to that in the GLM medium. However, the doping of Al is detrimental to the wear resistance of the T91 steel significantly at 400 °C by inhibiting the formation of the protective FeGa 3 film on the frictional interfaces, which readily appears at T91 frictional interfaces in the GLM medium. At 600 °C, Al atoms participate in the formation of a multilayer intermetallic film, thus improving the wear resistance again. This paper provides a new idea for preparing the metaldoped GLM and improving the lubricity of GLM, and it drives forward our understanding of the lubrication mechanisms of liquid lubricants.

Dialkyl Dithiophosphate-Functionalized Gallium-Based Liquid-Metal Nanodroplets as Lubricant Additives for Antiwear and Friction Reduction

“…To analyze the reasons behind the enhancement of the tribological performance of DDP@GLMs, the metal elements and corresponding oxides were tested on the worn surface by XPS. As shown in Figure , the Ga 2p 3/2 spectrum of DDP@GLMs additives displayed peaks at 1118.3 eV, which could be attributed to the formation of Ga 2 O 3 . The In 3d spectrum of the worn surface displayed two prominent peaks at 444.9 and 452.4 eV, corresponding to the In 2 O 3 .…”

“…Gallium-based liquid metal (GLM) exhibits exceptional chemical properties, such as high-temperature stability, high thermal conductivity, wide liquid range, low melting point, and nontoxicity. − This liquid lubricant appears to be the imminent additive for the aviation and nuclear industries . Tian et al proposed that GLM is capable of maintaining a decent lubrication performance even at a speed of 1800 rpm and under a heavy load of 10 kN (13.7 GPa friction pair contact stress) .…”

“…17−19 This liquid lubricant appears to be the imminent additive for the aviation and nuclear industries. 20 Tian et al proposed that GLM is capable of maintaining a decent lubrication performance even at a speed of 1800 rpm and under a heavy load of 10 kN (13.7 GPa friction pair contact stress). 21 Hu et al reported that GLM displays remarkable lubricating properties throughout an ultrawide range of temperature (from −10 to 800 °C).…”

Interfacial Rheology of Gallium-Based Liquid Metals

“…Thus, the oxide skin dominates the rheological behavior of the metal at small length scales where gravity is negligible and the ratio of gravitational force to surface tension, quantified by the Bond number, has a value less than 1. Based on the stabilizing effects of the oxide layer, liquid metals can be patterned into useful shapes to form soft electrodes, stretchable electrical conductors, and injectable components for microfluidics. − Recent studies have shown it is possible to alter the oxide layer by doping liquid metal with other metals. − The dopant will migrate to the interface if the Gibbs energy is favorable relative to gallium. In standard atmospheric conditions, the interfacial behavior of the oxide skin plays a prominent role in the mechanical properties of a broad class of liquid metals.…”

Investigating Liquid Metal Galinstan as a High Current Carrier and Its Interaction with Collector Electrodes

“…Therefore, liquid metals have been investigated as a possible lubricant at such contacts to minimize these problems. Guo et al 32 prepared Al-doped galinstan and reported that when used as a lubricant between T91 steel/steel contacts, it reduces the wear rate between the sliding pairs. They also investigated the lubrication mechanism of galinstan under current-carrying conditions and reported that galinstan can also lubricate the metal sliding pairs and reduce the wear rate under these conditions; 13 however, the applied current of 5 A was quite low.…”