A Fe-based amorphous/nanocrystalline coating was prepared on the AISI 321 steel by the high-velocity oxygen-fuel (HVOF) thermal spraying technology in this paper. Cavitation erosion behavior and mechanism of the coating was studied through the analysis of curves for cavitation erosion resistance versus time and the observation of eroded particles, with the AISI 321 steel as a reference. It was found that the Fe-based coating had better cavitation erosion resistance than the AISI 321 steel, and exhibited obvious periodic failure behavior in the cavitation erosion process. Besides, the crystallization of the amorphous phase under the effect of shock wave was observed. The cavitation erosion mathematic model of the coating was also established. The model indicated that the cavitation erosion resistance of the coating was related to the grain size and the fracture energy per unit area of the coating. Small grain size and high fracture energy per unit area were benefit to improve the cavitation erosion resistance of the Fe-based coating.

本文采用高速氧燃料（HVOF）热喷涂技术在AISI 321钢上制备了Fe基非晶/纳米晶涂层。通过分析抗气蚀性能随时间变化的曲线以及观察侵蚀颗粒，研究了涂层的气蚀行为和机理，并以AISI 321钢为参考。结果表明，铁基涂层比AISI 321钢具有更好的抗空蚀性能，并且在空蚀过程中表现出明显的周期性破坏行为。此外，观察到在冲击波作用下非晶相的结晶。建立了涂层的空化侵蚀数学模型。该模型表明，涂层的抗气蚀性与涂层的晶粒尺寸和单位面积的断裂能有关。小晶粒尺寸和高单位面积断裂能有利于提高铁基涂层的抗气蚀性能。