Cu-bearing 316L stainless steel coatings produced by laser melting deposition: Microstructure and corrosion behavior in simulated body fluids

In order to clarify the effect of copper contents on the corrosion resistance of stainless steel in biological environment, 316L-0Cu (wt%), 316L-1.5Cu (wt%), 316L-4.5Cu (wt%) and 316L-7.5Cu (wt%) coatings were prepared by laser melting deposition (LMD), and the microstructure and corrosion behavior in simulated body fluids (SBF) were studied. The results show that the planar growth, cellular crystal and dendritic microstructure are formed in the four kinds of LMD-produced coatings. With the increase of copper contents, the microstructure is refined, the corrosion resistance is decreased first and then is increased. This is because the copper oxide precipitates at the high-density grain boundaries, which can promote the passivation behavior. Under the combined action of Cr 2 O 3 and Cu 2 O, the corrosion resistance of 316L-7.5Cu coating is closest to that of 316L-0Cu coating. • Cu-bearing 316L SS coatings is produced by laser melting deposition (LMD). • The transitions of planar, cellular and dendritic crystals occur at the different locations of coatings. • The copper addition leads to the refinement of austenitic dendrites. • Fine grain and high-copper content can improve the corrosion resistance of 316L coatings in SBF.