Surface Chemistry and Semiconducting Properties of Passive Film and Corrosion Resistance of Annealed Surgical Stainless
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JMEPEG https://doi.org/10.1007/s11665-020-05067-3
Surface Chemistry and Semiconducting Properties of Passive Film and Corrosion Resistance of Annealed Surgical Stainless Steel Rodrigo Kenji de Oliveira, Olandir Vercino Correa, Mara Cristina Lopes de Oliveira, and Renato Altobelli Antunes (Submitted March 25, 2020; in revised form June 24, 2020) ASTM F-139 surgical stainless steel was subjected to annealing treatments at 700 °C for different times. The effect of annealing on the chemical composition of the passive film was evaluated by x-ray photoelectron spectroscopy. The correlation of the surface chemistry with the corrosion behavior and semiconducting properties of the passive film was also investigated. Potentiodynamic polarization tests were conducted in phosphate-buffered solution at 37°C. The semiconducting character of the passive film was assessed by the Mott–Schottky approach. The microstructure of the annealed samples was characterized by optical microscopy. The grain size increased after annealing, but the differences between each annealing condition were not significant and could not be associated with the corrosion behavior of the annealed samples. The corrosion resistance was improved depending on the heat treatment condition due to compositional changes of the passive film upon annealing. The best corrosion properties were observed after annealing for 8 h which was ascribed to Cr2O3, MoO3 and FeO enrichment in the passive film. Keywords
annealing treatments, surface chemistry
corrosion,
Mott–Schottky,
1. Introduction Austenitic stainless steels are commonly employed as biomedical devices especially for temporary applications such as plates and screws during fracture healing (Ref 1, 2). The surgical grade ASTM F-139 is the standard material for this usage owing to its adequate set of attributes relying on its mechanical strength, reasonable corrosion resistance, ease of manufacturing and low cost (Ref 3-5). It is, though, well known that it is prone to pitting corrosion in chloride-containing electrolytes such as the body fluid (Ref 6, 7). Stress corrosion cracking and corrosion fatigue of surgical stainless steels are often associated with the nucleation and growth of pits (Ref 810). It is, therefore, important to decrease its pitting corrosion susceptibility in order to reduce the risk of premature failures. Annealing treatments can affect the corrosion resistance of stainless steels. Microstructural changes originated from the heat treatments are closely related to the corrosion properties. Deng et al. (Ref 11) investigated the effect of annealing treatments on the pitting corrosion resistance of a super duplex stainless steel. Complex microstructural transformations can be
Rodrigo Kenji de Oliveira, Mara Cristina Lopes de Oliveira, and Renato Altobelli Antunes, Centro de Engenharia, Modelagem e Cieˆncias Sociais Aplicadas (CECS), Universidade Federal do ABC (UFABC), Santo Andre´, SP 09210-580, Brazil; and Olandir Vercino Correa, Centro de Cieˆncia e Tecnologia de Materiais (CCTM) – Instituto de Pe
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