Abstract:Two kinds of nanoparticles reinforced with Ni-based composite alloying layer were prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO2 and nano-SiC were firstly predeposited by brush plating. The microstructure of the two kinds of nanoparticles was investigated by XRD, SEM and TEM. Their corrosion resistance and erosion-corrosion resistance were analyzed by Tafel Plot, electrochemical impedance spectroscopy (EIS) and erosion-corrosion tests. The results indicate that under the alloying temperature (1000 oC) condition, the amorphous nano-SiO2 particles still kept the amorphous structure, whereas the nano-SiC particles was decomposed and Ni and Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. The corrosion test results indicate that the alloying layer reinforced by amorphous nano-SiO2 particles display passivation, and the pitting potential (Epit) and passive current (ip) are slightly smaller than that of single alloying layer, whereas the Ni-based alloying layer reinforced by nano-SiC particles is active in 3.5% NaCl solution (mass fraction, similarly hereinafter). The results of impedance spectroscopy of measured samples show that the Nyquist plots of Ni-based alloying layers consisted of single capacitance arc. Compared with the single alloying layer, the capacitance arc of the amorphous nano-SiO2 particles reinforced by Ni-based composite alloying layer is slightly decreased. The capacitance arc of alloying layer reinforced by nano-SiC particle is lower than that of the single alloying layer and nano-SiO2 particles reinforced by Ni-based composite alloying layer, but still higher than that of 316L substrate. The erosion-corrosion results indicate that the alloying layer reinforced by amorphous nano-SiO2 particles show the highest erosive-corrosive resistance of the three alloying layers, while the 316L stainless steel is the worst