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Corrosion of high‐velocity oxy‐fuel (HVOF) sprayed iron‐based amorphous metallic coatings for marine pump in sodium chloride solutions
Author(s) -
Wang Y.,
Zheng Y. G.,
Ke W.,
Sun W. H.,
Wang J. Q.
Publication year - 2012
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201106211
Subject(s) - materials science , corrosion , thermal spraying , passivation , metallurgy , amorphous solid , scanning electron microscope , porosity , microstructure , pitting corrosion , coating , ribbon , differential scanning calorimetry , alloy , composite material , chemistry , organic chemistry , layer (electronics) , physics , thermodynamics
FeCrMoMnWBCSi amorphous metallic coatings (AMCs) were deposited onto the 304 stainless steel (base material of pump impeller operated in sand‐containing seawater) by high‐velocity oxygen‐fuel (HVOF) thermal spray. The preparation, microstructural characteristics, and static corrosion behavior of the AMCs were presented. The microstructure and corrosion behavior of the AMCs were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and electrochemical methods. Melt‐spun ribbon and 304 stainless steel were also used for comparison purposes. The results indicated that the AMCs can spontaneously passivate with a wide passive region, and much higher ability to withstand pitting corrosion than that of the 304 stainless steel for the high pitting resistance equivalent value. The passive current density of the AMCs was at least two orders of magnitude higher than the counterpart ribbon, which showed a slightly decreased uniform corrosion resistance of the AMCs due to the incompact structure and porosity. The corrosion resistance of the AMCs increased with the coating thickness and decreased with the concentration of NaCl solution. A stable passivation ability held in the AMCs endowed them suitably used in marine environments.