Effects of Relaxation and Nanocrystallization on Wear and Corrosion Behaviors of Fe-Based Amorphous Coating

In this study, amorphous Fe60Nb3B17Si6Cr6Ni4Mo4 coatings were prepared using the high-velocity air fuel method. The microstructure, wear resistance, and corrosion resistance of the Fe60Nb3B17Si6Cr6Ni4Mo4 coatings were examined for various levels of nanocrystallization. In contrast to the as-sprayed coating, the samples that were heat-treated formed partial α-Fe and crystalline Cr2O3. The generated nanocrystals exerted a dispersion-strengthening effect on the coatings, leading to enhanced hardness and fracture toughness. When the annealing temperature was below the initial crystallization temperature, the wear resistance improved by approximately 1.65 times, the wear rate decreased to half of that in the as-sprayed state, and the depth of the wear scar reduced. However, the resistance of the coatings to corrosion deteriorated as the degree of crystallization increased. X-ray photoelectron spectroscopy analysis revealed that heat treatment modified the composition of the passive film, thereby influencing its corrosion resistance. These results provide crucial insights into the application of Fe-based amorphous coatings in wear- and corrosion-resistant environments.