Purpose
The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not uncovered obviously. In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys (x = 4, 8, 10 and 14) has been studied. This study aims to evaluate the rate of corrosion and corrosion resistance of some Fe–Cr–Ni alloys in SBF at 37°C.
Design/methodology/approach
In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys has been studied using open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in the SBF at 37°C and pH 7.4 for a week. Also, the surface morphology of the four alloys was investigated using scanning electron microscopy, elemental composition was obtained via energy dispersive spectroscopy and the crystal lattice structure of Fe–17Cr–xNi alloys was obtained using X-ray diffraction technique. The chemical structure of the protective oxide film has been examined by X-ray photoelectron spectroscopy (XPS) and metals ions released into the solution have been detected after different immersion time using atomic absorption spectroscopy.
Findings
The results revealed that the increase of the Ni content leads to the formation of the stable protective film on the alloys such as the Fe–17Cr–10Ni and Fe–17Cr–14Ni alloys which possess solid solution properties. The Fe–17Cr–14Ni alloy displayed highest resistance of corrosion, notable resistance for localized corrosion and the low corrosion rate in SBF because of the formation of a homogenously protective oxide film on the surface. The XPS analysis showed that the elemental Fe, Cr and Ni react with the electrolyte medium and the passive film is mainly composed of Cr2O3 with some amounts of Fe(II) hydroxide at pH 7.4.
Originality/value
This work includes important investigation to use commercial stainless steel alloys for biomedical application.
Electrocatalytic behavior of commercially available Fe-17Cr-14Ni alloy as a cathodic material for the evolution of hydrogen in alkaline solutions has been characterized by means of microstructural and electrochemical techniques. The microstructure of the alloys was examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. The electrochemical behavior of the examined materials was studied through potentiodynamic polarization techniques and electrochemical impedance spectroscopy (EIS). The effect of electrolyte concentration on the hydrogen evolution reaction (HER) rate and the cathode's electrochemical stability were studied. Tafel extrapolation method was used to determine the kinetic parameters characteristic of the hydrogen evolution reaction. The results show that the investigated alloy can be seen as a good candidate for large-scale and long-term hydrogen evolution. The rate of evolution of hydrogen under low overpotential is relatively high.
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