Dual-Phase Nanocomposite TiB₂/MoS_1.7B_0.3: An Excellent Ultralow Friction and Ultralow Wear Self-Lubricating Material

Abstract

Proper lubrication is essential to the reliable and efficient operation of mechanical systems ranging from the industrial to the nanoscale. Self-lubricating materials that can self-generate and sustain concurrent ultralow friction and ultralow wear in harsh environments open up a unique realm that is unattainable by traditional external lubrication mechanisms, but developing such extraordinary materials has been a long-standing grand challenge. Here, we devise an unconventional strategy to construct a dual-phase nanocomposite (DPNC) that comprises a wear-resistant phase (TiB2) and an internal lubricant source (MoS1.7B0.3). Tribological tests demonstrate simultaneous ultralow friction coefficient (∼0.03) and ultralow wear rate (∼10–10 mm3·N–1·m–1) of the synthesized DPNC specimen in ambient environments; these superb properties remain intact after the specimen has been annealed at 400 °C in air. First-principles energetic and stress–strain calculations elucidate atomistic mechanisms underpinning DPNC TiB2/MoS1.7B0.3 as an ultimate self-lubricating material. This accomplishment solves the classic lubricity–durability tradeoff dilemma, enabling advances to meet the most challenging lubrication needs.

Recent advances of two-dimensional lubricating materials: from tunable tribological properties to applications

“…In a typical study, the wear-resistant phases of TiB 2 and MoS 1.7 B 0.3 were sprayed to form dual-phase nanocomposite films (DPNC) by magnetron co-sputtering. 150 The highly wear-resistant phase TiB 2 could protect MoS 2 from mechanical degradation. The structural characterization showed the presence of sulfur vacancies in MoS 1.7 , while there was excess B in the TiB 2.3 lattice, which were matched and complementary through a stoichiometric angle, largely avoiding the obstacle of the existence of a single phase.…”

A Systematic Review of the Recent Advances in Superlubricity Research

“…The main types of liquid lubrication materials are as follows [169][170][171][172]: (1) waterlubricated ceramics-friction chemical reaction on ceramic surfaces when water is used as a lubricant; (2) acid-based liquids-the presence of hydrogen ions and hydrogen bonds is important for superlubricity to occur; (3) ionic liquids-ILs are representative lubricants and lubricant additives that significantly reduce friction and wear, and retard corrosion and mechanical failure; (4) polymer molecular brushes-osmotic pressure is generated between molecular brushes to withstand loads; (5) oil-based liquids-the viscosity of the lubricant has an effect on the coefficient of friction; (6) organism's mucus-this includes human joints, plant mucus, etc. ; (7) black phosphorus (BP)-BP is an emerging superlubricity material.…”