Preparation And Properties Of Cu Based Composite Coatings

Cu-Ni alloy coatings with different Cu:Ni ratios were prepared by changing current densities,bath temperature and pH value,and nanostructured Cu-Ni-TiO₂ composite coatings with different nano-TiO₂ particle content were prepared.The microstructures,mechanical,corrosion and photocatalysis degradation properties of the coatings were investigated by scanning electron microscopy?SEM?,energy dispersive spectrometer?EDS?,X-ray diffractometer?XRD?,microhardness tester,friction wear testing machine,electrochemical workstation and UV spectrometer photometer.The Cu-Ni coatings with different Cu:Ni ratios were prepared.The XRD results showed that the Cu-Ni alloy coating exhibited in Cu?111?,Cu?200?and Cu?220?planes with a preferred orientation at the?111?diffraction plane.When current density and pH values increased,the Cu content in the Cu-Ni coatings gradually decreased whereas Ni content increased.On the contrary,with the increase in bath temperature,the Cu content gradually increased while the Ni content decreased.With the increase of current density,the grain size of Cu-Ni coating slowly increased,and the compactness decreased.At 15mA/cm²,the coating had the highest hardness,the best wear and corrosion resistance,and the release amount of Cu²⁺and N²⁺ions was the least in 3.5%NaCl solution.With increasing the temperature,the compactness of Cu-Ni coating was improved and the porosity was reduced;And the coating formed at 55oC possessed the highest microhardness,the best wear and corrosion resistance,and the least ion release amount of Cu²⁺and N²⁺in 3.5%NaCl solution.When the pH values increased,the Cu-Ni coatings were more and more compact,the coating formed at pH 7 exhibited the highest wear and corrosion resistance,and the least ion release amount of Cu²⁺and N²⁺in 3.5%NaCl solution.The Cu-Ni-TiO₂ composite coatings with different TiO₂ nanoparticles were prepared,the coatings had a preferred orientation at the Cu?111?crystal plane.With the increase in content of TiO₂ nanoparticles in the plating solution,the coating microstructure become fine,even and compact.The composite coating prepared in plating solution of 8 g/L TiO₂nanoparticles had the highest hardness,the best wear and corrosion resistance,the least ion release amount of Cu²⁺and N²⁺in 3.5%NaCl solution.Meantime,the decolorization rate of methyl orange under UV irradiation was the highest.