High-temperature solid lubrication applications of Transition Metal Dichalcogenides (TMDCs) MX2: A review

With the rapid advancement of science and technology, along with an increasing global focus on space exploration, there is a growing concern for addressing friction and wear issues in surface coatings for components operating in high-temperature environments within the aerospace sector. However, typical high-temperature coatings currently face challenges in effectively integrating excellent oxidation resistance, wear resistance, and lubrication properties in high-temperature settings. Studies have demonstrated the significant potential of Transition Metal Dichalcogenides (TMDCs) as lubricant additives in high-temperature lubrication, attributable to their distinctive crystal structures. Thus, this review concentrates on the compositional design of individual MX₂-type (M ​= ​W, Mo, Nb, Ta; X ​= ​S, Se) TMDCs (molybdenum disulfide (MoS₂), tungsten disulfide (WS₂), niobium diselenide (NbSe₂), molybdenum diselenide (MoSe₂), tungsten diselenide (WSe₂)) and their composites, including inorganic oxygen-containing sulfides, and explores the utilization of TMDCs in self-lubricating coatings. Furthermore, conventional preparation methods (mechanical exfoliation, liquid-phase ultrasonic exfoliation, chemical vapour deposition) for synthesizing TMDCs are outlined. Finally, an analysis of the lubrication mechanism of MX₂-type TMDCs is provided, along with future directions for enhancing the high-temperature lubrication performance of composite coatings.