Erosion–corrosion characteristic of nano‐particulates reinforced Ni–Cr–Mo–Cu surface alloying layer in acidic flow and acidic slurry flow

Abstract

In order to improve the corrosion and erosion-corrosion resistance of 316L stainless steel in engineering application, two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO 2 predeposited by brush plating, respectively, and a subsequent surface alloying with Ni-Cr-Mo-Cu by double glow process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were performed on the two kinds of composite alloying layer using 10 wt% HCl solution to assess the corrosion behavior. Erosion-corrosion tests were carried out by erosion-corrosion test rig in acidic flow and acidic slurry flow for test time of 20 h at four different rotational speeds. Results of electrochemical tests indicated that the corrosion resistance of composite alloying layer with brush plating Ni/nano-SiO 2 particles interlayer approximated to that of single Ni-based alloying layer, whereas the corrosion resistance of the composite alloying layer with brush plating Ni/nano-SiC particles interlayer was apparently inferior to that of Ni-based alloying layer in 10 wt% HCl solution at static state. Under the conditions of acidic flow and acidic slurry flow, the mass losses of tested samples increased with increase in the time of erosion-corrosion tests and the rotational speeds of samples. The mass losses of composite alloying layer with brush plating Ni/nano-SiO 2 particles interlayer were lower than that of single Ni-based alloying layer at all rotational speeds, except at 1.88 m/s in acidic flow. The mass losses of composite alloying layer with brush plating Ni/nano-SiC particles interlayer were higher than that of single Ni-based alloying layer at all rotational speeds, but were obviously lower than that of AISI 316L stainless steel. The influences of second phase on the corrosion and erosion-corrosion of the two kinds of composite alloying layer were discussed in this paper.