Effect of current density on microstructure and corrosion resistance of electrodeposited CoCrNi medium-entropy alloy film
[Introduction]CoCrNi medium-entropy alloy is mostly prepared by powder metallurgy,melting,and other methods,which has the problems of cumbersome operation and high cost.Electrodeposition technology not only has the advantages of simple operation,low cost,and less energy consumption,but also allows the composition and organization of deposit to be regulated by changing the process parameters.[Method]CoCrNi medium-entropy alloy films were prepared on copper substrate by electrodeposition under direct current density.The phase structure,morphology,and element distribution of CoCrNi medium-entropy alloy films electrodeposited at different current densities were analyzed by X-ray diffraction(XRD),field-emission electron probe microanalysis(FE-EPMA),and energy-dispersive spectroscopy(EDS),respectively.The effect of current density on the corrosion resistance of CoCrNi alloy film was studied by electrochemical measurements.[Result]The electrodeposited CoCrNi alloy film consists of spherical particles and particle clusters with an amorphous structure.All of the elements i.e.Co,Cr,and Ni were uniformly distributed through the alloy film.With the increasing of current density,the mass fraction of Cr was initially increased and then stabilized,the mass fraction of Ni was decreased firstly and then stabilized,while the mass fraction of Ni was almost unchanged.With the increasing of Cr content,the microhardness of CoCrNi alloy film was increased,accompanied with the appearance of some microcracks,and its corrosion resistance get better initially and then worse.[Conclusion]Current density has great impact on the corrosion resistance of CoCrNi medium-entropy alloy film.The CoCrNi film electrodeposited at 100 mA/cm2 has the best corrosion resistance despite the presence of some microcracks.
direct current electrodepositioncobalt-chromium-nickel medium-entropy alloy filmmicrostructurecorrosion resistance
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