Microstructure and Properties of Fe-based Amorphous/Nanocrystalline Coating Prepared by Arc Surface Welding

The Fe-based amorphous/nanocrystalline coating was prepared by combining the properties of the amorphous alloy with surface welding. The microstructure of the coating was investigated by scanning election microscopy equipped with energy-dispersive spectroscopy, transmission electron microscopy and x-ray diffraction. The thermal stability and crystallization behavior were characterized by differential scanning calorimetry. The corrosion behavior of the coating under different heat treatments was evaluated by electrochemical measurement. The results showed that the surface coating had a mixed microstructure composed of amorphous phases and nanocrystallines. Moreover, the coating was well metallurgically bonded with the substrate and had good thermal stability. However, the proportion of amorphous phase in the coating decreased to 40%, 27%, 15% and 9% after heat treatment at 550°C, 600°C, 650°C and 700°C. The corrosion resistance of the coating was first improved at 550°C but decreased as the annealing temperature increased further.