Effect of copper addition on the microstructure, wear resistance, anti-corrosion and antibacterial behavior of laser cladding CoCrW coatings in marine environment

Abstract

In response to the issues of wear corrosion and marine bio-erosion faced by aluminum alloy surfaces in marine environments, a series of laser cladding CoCrW-xCu (x = 0, 2, 4, 8) coatings with good metallurgical bonding were prepared on the aluminum surface. The results showed that the addition of Cu by in situ alloying resulted in an increase in the concentration of high-angle grain boundaries (HAGBs) in the coatings and altered the thermodynamic stability of the coating surface. Meanwhile, the addition of copper affected the Co, Cr and W elemental segregation at crystal boundaries and crystal interiors. The synergistic effect of Co, Cr, W and Cu led to the fewest point defects in the passive film of CoCrW-2Cu and the densest film, effectively reducing the likelihood of film breakdown. Thereby the CoCrW-2Cu coating exhibited the best corrosion resistance and wear resistance, with the wear mechanisms being abrasive wear, slight adhesive wear and corrosive wear. In addition, the Cu-containing coatings exhibited remarkable antibacterial properties. This study holds significant theoretical value and practical implications for the application of aluminum alloy components in marine equipment.