45^# steel is widely used in key fields such as mechanical manufacturing and automotive components due to its excellent comprehensive mechanical properties and relatively low cost. However, its inherent limitations including low microhardness, and insufficient wear and corrosion resistance seriously restrict its service life and reliability in harsh environments. To solve this problem, this study uses laser cladding technology to prepare a wear-resistant coating on the surface of 45^# steel, aiming to improve its wear resistance under harsh working conditions and extend its service life.

In this study, CeO₂/Ni/WC composite coatings with different molybdenum (Mo) contents were successfully prepared on the surface of 45^# steel using laser cladding technology (Table 2). The influence patterns and mechanisms of Mo mass fraction (0%~4%) on the microstructure, phase composition, microhardness, and dry sliding friction and wear properties of the coatings were systematically investigated. A comprehensive characterization was conducted using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness tester, and friction and wear testing machine.

The results showed that the addition of an appropriate amount of Mo could significantly refine coating grains, promote the formation and dispersion of high-hardness MoC phase, and produce a solid solution strengthening effect. When the Mo mass fraction was 2%, the coating exhibited the optimal comprehensive performance. The microstructure was the most uniform and refined (Fig.2). The average microhardness reached a peak of 840.74 HV, 11.32% higher than that without Mo coating (Fig.5). The wear amount decreased to a minimum of 2.1 × 10⁻³ mm³, with a reduction of 41.66% (Fig.6), and the wear mechanism changed from severe abrasive-fatigue composite wear to slight abrasive wear (Fig.7). This was attributed to the synergistic effect of fine grain strengthening, dispersion strengthening, and the MoO₃ self-lubricating film formed by tribo-oxidation.

This study elucidates the synergistic mechanisms of microstructure refinement, multi-element strengthening, and surface lubrication of Mo in a specific composite system, and determines the optimal mass fraction of Mo in this composite system, thereby providing an important theoretical and experimental basis for the design and development of high-performance laser cladding wear-resistant coatings.