Potentiodynamic tests and electrochemical impedance spectroscopy of injection molded 316L steel in NaCl solution

• Published in: Corrosion science 2001-06, Vol.43 (6), p.1019-1030
• Main Authors: Sobral, Ana V.C., Ristow, W., Azambuja, Denise S., Costa, Isolda, Franco, César V.
• Format: Article
• Language: English
• Subjects: Applied sciences; Corrosion; Corrosion tests; Electrochemical impedance spectroscopy; Exact sciences and technology; Injection molding; Metals. Metallurgy; Sintered steel
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/S0010-938X(00)00140-2

Cyclic polarization tests of injection molded 316L steel were carried out in 3% NaCl solution. The microstructure of the as-tested samples was studied by optical and scanning electron microscopy. The corrosion resistance of injection molded 316L steel was also evaluated studying the evolution of electrochemical impedance spectroscopy at the open-circuit potential for immersion periods varying from 1 to 78 days in aerated salt solution. The penetration of the electrolyte solution through surface open pores as a function of the immersion time has also been addressed so the effect of porosity on the corrosion behavior was investigated. The results demonstrated that the corrosion resistance of the injected steel is affected by the presence of open pores, as they act towards increasing the effective surface area of the material. This fact was confirmed by an increase in the corresponding value of the double layer capacitance, C dc, and a decrease in the value of the charge transfer resistance, R t.