Synthesis of MXene-Based Self-dispersing Additives for Enhanced Tribological Properties

As an emerging class of the two-dimensional (2D) materials, MXenes exhibit excellent antifriction and wear resistance potential in lubrication systems. However, as a lubricant additive, their stable dispersion in base oils remains a great challenge. Optimizing the microstructure has previously been demonstrated to be an effective strategy to improve the dispersibility of inorganic materials in oil-based lubricants. In this work, the structural modulation of MXene through in-situ growth of hydroxysalts (HS) to form a heterostructure was achieved. Compared with pristine MXene and HS, the dispersion stability of MXene/HS composite in poly-alpha-olefin-10 (PAO-10) base oil was significantly improved due to the self-dispersion and restacking-resistant properties of the heterostructure. Additionally, the lubrication performance of the obtained composite as an additive in PAO-10 was investigated. The results showed that the coefficient of friction of the oil sample containing the MXene/HS composite was steadily maintained at approximately 0.12 under four different loads of 200, 250, 300, and 350 N (corresponding to maximum Hertz contact pressures of 2.72, 2.9, 3.12, and 3.28 GPa, respectively). Moreover, the wear track width, wear scar diameter, and wear volume were reduced by 49.1%, 49.4%, and 82.0%, respectively. This study introduces a viable pathway to transform non-lipophilic Ti3C2Tx MXene into an attractive lubricant additive with excellent self-dispersing ability through structural regulation. [GRAPHICS] .

Automated summary

As an emerging class of two-dimensional materials, MXenes show great potential in lubrication systems for their excellent antifriction and wear resistance. However, achieving stable dispersion of MXenes in base oils remains a challenge. In this study, the microstructure of MXene was modulated through in-situ growth of hydroxysalts, forming a heterostructure that significantly improved dispersion stability in poly-alpha-olefin-10 base oil. The obtained MXene/hydroxysalts composite exhibited steady and reduced friction coefficient as well as decreased wear track dimensions, showing promise as a lubricant additive.