Enhancement of the corrosion properties of cold sprayed Ti–6Al–4V coatings on mild steel via silica sealer

The pore formation associated with the cold spray process requires the development of an economical sealer to enhance the corrosion resistance of Ti–6Al–4V coatings on a mild steel substrate. Herein, a sound method is developed to seal pores in the cold sprayed Ti–6Al–4V coatings with silica sealer....

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Veröffentlicht in:Materials and corrosion 2022-01, Vol.73 (1), p.20-30
Hauptverfasser: Morks, Magdi F., Zahiri, Saden, Chen, Xiao‐Bo, Gulizia, Stefan, Cole, Ivan S.
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Sprache:eng
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Zusammenfassung:The pore formation associated with the cold spray process requires the development of an economical sealer to enhance the corrosion resistance of Ti–6Al–4V coatings on a mild steel substrate. Herein, a sound method is developed to seal pores in the cold sprayed Ti–6Al–4V coatings with silica sealer. Potentiodynamic polarization tests in 3.5 wt% sodium chloride electrolyte were employed to investigate the corrosion resistance of cold sprayed Ti–6Al–4V coatings fabricated at two standoff distances (30 and 70 mm) before and after the sealing process. The polarization resistance of cold sprayed Ti–6Al–4V coatings significantly increased by >80% after the sealing process. The electrochemical responses of cold sprayed Ti–6Al–4V were dependant on sealing the pores with agglomerated silica nanoparticles as observed by scanning electron microscopy and energy‐dispersive X‐ray analysis. The increase in polarization resistance makes the sealer an effective treatment for cold sprayed Ti–6Al–4V coatings used in marine environments and other engineering applications. This sophisticated sealing process can reduce the deposition cost by reducing the thickness of Ti–6Al–4V coatings and increasing their lifetime on metal components. Pores in the cold sprayed Ti–6Al–4V coatings on mild steel have a significant impact on the corrosion properties. The coating failure occurs when the corrosive species penetrate the protective coating through the open pores and reach the substrate materials. Therefore, sealing the open pores are critical to enhancing corrosion resistance. Nano‐silica sealer—in the liquid state—is a potential ceramic material to fill the pores with nano‐silica particles.
ISSN:0947-5117
1521-4176
DOI:10.1002/maco.202112504