The study of mechanical properties and corrosion behavior of the Fe-based amorphous alloy coatings using high velocity oxygen fuel spraying

Abstract

• Prepared Fe-based amorphous alloy with high hardness and corrosion resistance by high velocity oxygen fuel spraying. • Used cold and hot alternating salt spray corrosion test and high-speed water erosion to simulate ocean atmosphere climate. • The corrosion behaviors of Mo and Cr elements between Fe-based substrates and Fe-based amorphous alloys coatings. The Fe-based amorphous alloy powders Fe 40 -Cr 19 -Mo 18 -C 15 -B 8 are sprayed on 316 stainless steel substrates by high velocity oxygen fuel spraying (HVOF) process. The microstructure of coatings are analyzed by XRD, SEM, XPS and TEM. The corrosion behavior of coatings under different corrosive solutions is also studied. The experimental results presented that the average hardness of coating is approximately at 1024 Hv, contact angle is from 72° to 74°. The scratch test result shows that the LC 2 value of coatings occurred at 46.0 N. SEM images presented that there are micro-holes and micro-cracks in coatings. XRD pattern and TEM images indicated the microstructure of coatings are the amorphous structure and amorphous/crystalline mixed structure. The potentiodynamic polarization analysis results show the corrosion resistance of coatings under sea water and 3.5 wt% NaCl solution has a transition behaviors of activation, passivation and over passivation. Through the cold and heat alternating salt spray corrosion test and the high-speed water erosion test, the surface of coatings rusted after 12 weeks. The surface of coatings formed passivation film during corrosion test, and it has a very slight weight loss. It can be seen that the Fe-based amorphous alloy has a good stable passivation and a corrosion-resistant.