Effect of Modulation Period on the Cavitation Erosion Resistance of TiSiN/AlCrTiVNbN Nanomultilayer Films

Cavitation erosion severely limits the service life of marine hydraulic components. Magnetron sputtering was utilized to fabricate TiSiN/AlCrTiVNbN high-entropy nitride nanomultilayer films, whose modulation periods ranged from 4 nm to 23 nm. The effects of modulation period on the microstructure, mechanical properties, and cavitation erosion resistance were systematically investigated. All films exhibited a single-phase face-centered cubic structure with a preferred orientation (200) plane. The film with a 6 nm layer period reached the highest hardness (38.9 GPa) and elastic modulus (214.1 GPa), which is due to the many closely fitting interfaces that effectively stopped line defect movement; in cavitation erosion tests in 3.5% salt water, this film had the lowest mass loss (0.8 mg) and its surface stayed in the best condition. Its superior cavitation erosion resistance originates from the synergistic effects of high-density coherent interfaces that obstructed crack propagation, enhanced mechanical properties that provided excellent resistance to plastic deformation, and the formation of a protective oxide layer during cavitation. As this work shows, optimizing the layer period is an effective strategy; it allows the design of strong protective films for ocean use.