A comparative study on the inhibition of microalgae attachment performance between Cu-based alloy laser cladding layer containing submicron Cr-rich precipitated phases and copper in simulated seawater

Abstract

Copper alloys are prominent materials in ships and marine engineering structures due to their effective antifouling performance. However, the deposition of insoluble corrosion products dramatically deteriorates their antifouling performance during long-term immersion. To solve this conundrum, we have developed a novel Cu-based alloy cladding layer containing submicron Cr-rich precipitates, which aims to promote the corrosion products flaking through the effect of precipitates, thus effectively inhibiting microalgae attachment. After being immersed for 180 days, the coverage rates of microalgae on the cladding layer were below 2%, while those on the copper exceeded 40%. The remarkable inhibition of microalgae attachment achieved by the cladding layer is mainly due to the Cr-rich precipitates embedded in the unique and loose multi-layer structure corrosion product as Cr2O3-rich particles, which promotes the corrosion product cracking and flaking. Thereby, the cladding layer kills attached microalgae by increasing their reactive oxygen species (ROS) levels.