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3890 |
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Corrosion behavior of arc sprayed stainless steel coating |
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Yamina Mebdoua Lahmar* / Centre de développement des technologies Avancées, Algérie Sofiane Djeraf / Centre de Développement des Technologies Avancées, Algeria Yamina Mebdoua/ CDTA, Algeria Hadj Lahmar/ CDTA, Algeria Yazid Fizi/ CDTA, Algeria |
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In this paper, electrochemical tests were performed on wire arc sprayed 316 stainless steel deposited on C35 steel substrate. The corrosion behavior of the coatings in various solutions as NaCl and H2SO4 as well as their microstructure study were investigated taking into account the effect of the heat treatment of the coating on their corrosion resistance, the obtained results were compared to the behavior of the stainless steel bulk material. The corrosion behavior of the coatings was investigated by the electrochemical polarization measurements in 3,5 % NaCl solution and H2SO4 2M. Open-circuit potential measurements, potentiodynamic polarization, electrochemical impedance spectroscopy and porosity measurements were performed. The electrochemical behavior of the stainless steel coatings mainly depend on the coating porosity, the presence of micro- cracks, and the inclusion of un-melted particles in the coating. Once the electrolyte reached the steel substrate via these defects, the galvanic pair formed between the coating and substrate accelerated corrosion, leading to the depletion of the coating. Coatings obtained using 100 mm spraying distance and a post annealing have presented the best electrochemical and corrosion resistance. |