Effect Of Cryogenic Treatment On Corrosion Resistance Of Fe Based Amorphous Coatings

In order to investigate the effect of cryogenic treatment on the corrosion resistance of Fe-based amorphous composite coating,the coating was prepared by the high velocity oxygen fuel(HVOF)spraying,then the cryogenic treatment is carried out at different times.The coatings with different cryogenic treatment time are analyzed by the electrochemical test,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS)and X ray photoelectron spectroscopy(XPS),and the mechanism of improving the corrosion resistance is also investigated.The results of XRD show that the average interatomic distance increases,and the cryogenic treatment at different time has a significant effect on the microstructure of the Fe based amorphous composite coatings.The electrochemical results show that the corrosion current passivation platform reduces for the Fe based amorphous composite coatings after the cryogenic treatment,indicating that the cryogenic treatment can improve the corrosion resistance of the coating.The 4h cryogenic time passivation platform is the lowest,showing the passivation state is the best during the cryogenic process.In addition,when the NaCl concentration is 0.1wt%in cryogenic treatment,the cryogenic treatment on the corrosion resistance of the coating has the greatest effect.According to the results of SEM,the composite coating without the cryogenic treatment is the uniform corrosion,while the coating after the cryogenic treatment is the spitting corrosion.The results of EDS show that the Fe based amorphous composite coating of Mo is higher in the local zone after the 4h cryogenic treatment.During the electrochemical corrosion process,the oxide passivation film is more denser,improving the corrosion resistance.The XPS results show that both CrOX/Crm and MoOX/Mom ratio of the Fe based amorphous composite coating film after 4h cryogenic treatment are increased than those of other cryogenic treatments,confirming that of the formation of a more stable and thick oxide film in the electrochemical corrosion process.so as to improve the corrosion resistance of the Fe based amorphous composite coating.