Corrosion behavior of FeCrSiB alloy coatings prepared by HVOF thermal spraying

FeCrSiB alloy coatings were prepared on Q235 steel substrate by high velocity oxygen fuel (HVOF) spray process. The microstructure and corrosion resistance of the deposited coatings were investigated by means of X-ray diffraction (XRD),scanning electron microscopy (SEM) and corrosion resistance evaluation equipments. It was found that the coatings exhibited dense structure with the porosity of 0.65% and compact bonding with the substrate. Electrochemical tests indicate that the FeCrSiB coatings underwent the subsequent processes of active solution,passivation,and repassivation in 3.5% NaCl solution, 1 mol/L HCl solution and 1 mol/L NaOH solution. Compared to the electrodeposited chromium coatings,FeCrSiB coating had better corrosion resistance in 3.5% NaCl solution and 1 mol/L HCl solution but worse corrosion resistance in 1 mol/L NaOH solution.