Cavitation-silt erosion behavior and mechanism in simulated sea water slurries of cermet coatings manufactured by HVOF spraying

Understanding the interaction between the sea water slurries and flow-handling components is important for enhancing the cavitation-silt erosion (CSE) resistance of the ocean power generation systems. In this manuscript, two cermet coatings (i.e., Cr3C2-25(NiCr) coating and WC-10(Ni) coating) were manufactured via a high-velocity oxygen fuel (HVOF) spraying method, and influences of sand concentrations (SCs) as well as flow velocities (FVs) on their CSE characteristics in simulated sea water slurries (SSWS) were investigated. Results indicated that the Cr3C2-25(NiCr) coating exhibited larger porosity, lower hardness (H) and elastic modulus (E), stronger ability to resist corrosion in 3.5 wt% saline solution as well as worse CSE resistance in SSWS, and its CSE resistance was more affected by both the SC and FV by comparison to the WC-10(Ni) coating. Both SC and FV had a positive effect on the CSE damage for the Cr3C2-25(NiCr) and WC-10(Ni) coatings, while SC had more influence on their CSE resistances than FV. The CSE deterioration mechanisms in SSWS under different SCs and FVs of the Cr3C2-25 (NiCr) and WC-10(Ni) coatings were also compared and revealed.

Automated summary

In this study, two cermet coatings were manufactured and their resistance to cavitation-silt erosion in simulated sea water slurries was investigated. The results showed that the Cr3C2-25(NiCr) coating had worse CSE resistance compared to the WC-10(Ni) coating, and its resistance was more affected by sand concentration and flow velocity. Both sand concentration and flow velocity had a positive effect on the CSE damage for both coatings, but sand concentration had a greater influence. The deterioration mechanisms of the coatings under different sand concentrations and flow velocities were also compared and revealed.