Dual-Phase Nanocomposite TiB<sub>2</sub>/MoS<sub>1.7</sub>B<sub>0.3</sub>: An Excellent Ultralow Friction and Ultralow Wear Self-Lubricating Material
Jingjie Pan, Chang Liu, Xinxin Gao, Kan Zhang, Weitao Zheng, Changfeng Chen
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.