As a core component of industrial power transmission and motion control, the surface quality and dynamic performance of gears are pivotal to the transmission efficiency, durability, and reliability of mechanical equipment. Driven by extreme service conditions and the demands of high-precision applications, surface lubrication failures (such as contact fatigue and scuffing) have become a critical bottleneck limiting gear performance, making the development of advanced surface-strengthening technologies a vital direction for industrial innovation. This paper provides a systematic review of research progress in gear-related surface-strengthening technologies, with a particular focus on techniques for preparing solid lubricant layers. It elaborates on the microstructures, lubrication mechanisms, and application performance of typical solid lubricant layers (e.g., iron sulfides, nitrides, molybdenum disulfide (MoS2), diamond-like carbon (DLC) films, and graphite-like carbon (GLC) films) in gear systems. Furthermore, it offers an in-depth analysis of the synergistic mechanisms between single-surface treatments and composite-strengthening processes. Additionally, it outlines innovative applications of additive manufacturing (AM) in gear manufacturing.
Zhang et al. (Sat,) studied this question.