The coupling effect of immersion corrosion and cavitation erosion of NiCoCrAlYTa coatings in artificial seawater

The coupling effect of immersion corrosion and cavitation erosion of HVOF-sprayed NiCoCrAlYTa coatings in artificial seawater is studied, in this work. The oxidized zone and its boundary on the coating surface are corroded, preferentially. Interestingly, an (Al, Cr)-rich passive scale forms on the coating surface after immersion corrosion, which would enhance its mechanical and anti-corrosion properties. The coating presents better cavitation erosion resistance, despite the coupling effect between corrosion and cavitation erosion causes the aggravation of the cavitation damage. The cavitation loss mainly is attributed to the fatigue failure and spalling of splats in the coatings.