Immersion corrosion and electrochemical performances of laser cladded FeSiB, FeSiBCr and FeSiBCrMo coatings in 3.5 wt% NaCl solution

摘要

FeSiB, FeSiBCr and FeSiBCrMo coatings were laser cladded on S355 steel using a pre-placed powder method. The surface and cross-section morphologies, chemical elements and phases of obtained coatings was analyzed using a scanning electron microscope (SEM), energy dispersive spectroscope (EDS), and X-ray diffraction (XRD), respectively, and the effects of Cr and Mo additions on the immersion corrosion and electrochemical performances of obtained coatings in 3.5 wt% NaCl solution for 720 h were analyzed. The result shows that the amorphous area fractions of FeSiB, FeSiBCr and FeSiBCrMo coatings are 7.27, 10.51, and 10.07%, respectively. The immersion corrosion rates of FeSiB, FeSiBCr and FeSiBCrMo coatings are 68.4, 31.6 and 27.6 wn/year, respectively, and the corresponding polarization resistances are 5464, 12,645, and 19,016 Omega.cm(2), respectively. The Cr2O3 passivation film is formed and further improved by the additions of Cr and Mo, respectively, which inhibits the occurrences of immersion and electrochemical corrosions.