Electrochemical behaviour of some commercial stainless steel alloys in simulated body fluid electrolytes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
A. Bahrawy ◽  
Mohamed El-Rabiei ◽  
Hesham Elfiky ◽  
Nady Elsayed ◽  
Mohammed Arafa ◽  
...  

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.

2011 ◽  
Vol 471-472 ◽  
pp. 325-330 ◽  
Author(s):  
K. Venkateswarlu ◽  
N. Rameshbabu ◽  
Arumugam Chandra Bose ◽  
V. Muthupandi ◽  
S. Subramanian

Nanostructured titania/hydroxyapatite (HA) composite layer was developed on commercially pure titanium (Cp Ti) implant material by plasma electrolytic processing (PEP) technique in order to improve its bioactivity and corrosion resistance under physiological conditions. The phases present in the developed composite layer were studied by X-ray diffraction (XRD) technique. The surface morphology and thickness of the composite layers were observed by scanning electron microscopy (SEM). The corrosion characteristics of the developed layer were studied by potentiodynamic polarization scan under simulated body fluid (7.4 pH Hanks solution) and simulated osteoclast (4.5 pH) conditions. The in-vitro bioactivity of the composite layers was studied by using Kokubu’s simulated body fluid (SBF) solution. The X-ray diffractograms reveal the presence of anatase TiO2 and HA phases in the developed layer. The SEM results confirm the pore-free morphology of the implant material surface and the thickness of the developed composite layer was observed to be 110 ± 5 µm for 12 min of PEP. The potentiodynamic polarization study shows an improved corrosion resistance and the in-vitro bioactivity test results indicate enhanced apatite forming ability of PEP treated Cp Ti surfaces compared to that of the untreated Cp Ti, under simulated body fluid conditions.


2020 ◽  
Vol 71 (6) ◽  
pp. 96-110
Author(s):  
Omyma Ramadan Mohammed Khalifa ◽  
Abdel-Wahab Abd Elhamid Ali ◽  
Aisha Kassab ◽  
Amal Hemida Tilp ◽  
Marwa Mohamed Mohamed Mohamed Esmail

In recent years, smart implants take the most attention in the field of bone manufacturing. Our study seeks to develop the biodegradability of Mg alloys to use orthopedic implants for the biomedical applications to avoid post removal of the implant. Mg and Zn are very important to human body and have no toxicity. Mg - 6% wt Zn biodegradability is studied in simulated body fluid for two and four weeks. Four electro-deposition bathes are used to deposit a coat on the substrate to improve the corrosion resistance of this alloy in the media of simulated body fluid. The following analyses were studied to emphasize the research aim. Scanning electron microscope (SEM), Energy dispersive X-Ray (EDX) analysis shows the surface morphology and the elements of the coat phases components. The results also confirmed by X-Ray diffraction Pattern (XRD) that show the phases that confirmed the formation of hydroxyapatite HA phase, Fourier-Transform Infrared Spectroscopy (FTIR) to investigate the functional groups of the phases coats that confirm the formation of hydroxyapatite and the electrochemical measurements that investigate the improvement of corrosion resistance. The results indicated that the fourth bath gives the best coat and four weeks immersion gives more corrosion resistance than two weeks.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 659
Author(s):  
Rebeka Rudolf ◽  
Aleš Stambolić ◽  
Aleksandra Kocijan

Nitinol is a group of nearly equiatomic alloys composed of nickel and titanium, which was developed in the 1970s. Its properties, such as superelasticity and Shape Memory Effect, have enabled its use, especially for biomedical purposes. Due to the fact that Nitinol exhibits good corrosion resistance in a chloride environment, an unusual combination of strength and ductility, a high tendency for self-passivation, high fatigue strength, low Young’s modulus and excellent biocompatibility, its use is still increasing. In this research, Atomic Layer Deposition (ALD) experiments were performed on a continuous vertical cast (CVC) NiTi rod (made in-house) and on commercial Nitinol as the control material, which was already in the rolled state. The ALD deposition of the TiO2 layer was accomplished in a Beneq TFS 200 system at 250 °C. The pulsing times for TiCl4 and H2O were 250 ms and 180 ms, followed by appropriate purge cycles with nitrogen (3 s after the TiCl4 and 2 s after the H2O pulses). After 1100 repeated cycles of ALD depositing, the average thickness of the TiO2 layer for the CVC NiTi rod was 52.2 nm and for the commercial Nitinol, it was 51.7 nm, which was confirmed by X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscope (SEM) using Energy-dispersive X-ray (EDX) spectroscopy. The behaviour of the CVC NiTi and commercial Nitinol with and without the TiO2 layer was investigated in a simulated body fluid at body temperature (37 °C) to explain their corrosion resistance. Potentiodynamic polarisation measurements showed that the lowest corrosion current density (0.16 μA/cm2) and the wider passive region were achieved by the commercial NiTi with TiO2. Electrochemical Impedance Spectroscopy measurements revealed that the CVC NiTi rod and the commercial Nitinol have, for the first 48 h of immersion, only resistance through the oxide layer, as a consequence of the thin and compact layer. On the other hand, the TiO2/CVC NiTi rod and TiO2/commercial Nitinol had resistances through the oxide and porous layers the entire immersion time since the TiO2 layer was formatted on the surfaces.


Author(s):  
Lilian N. M. Braguin ◽  
Caio A. J. da Silva ◽  
Larissa O. Berbel ◽  
Isolda Costa ◽  
Mitiko Saiki

The ISO 5832-1 austenitic stainless steel used as biomaterial is largely applied in the area of orthopedics, especially in the manufacture of implants, such as temporary or permanent replacement of bone structures. The objective of this study was to evaluate the localized corrosion resistance of the ISO 5832-1 stainless steel used in orthopedic implants by electrochemical tests in two different solutions. The results of this study are of great interest to evaluate the corrosion of metallic implants that can result in the release of corrosion products into bodily fluids causing possible adverse biological reactions. The determination of the chemical elements in the composition of the ISO 5832-1 stainless steel was performed by neutron activation analysis (NAA). The samples for electrochemical tests were grinded with silicon carbide paper up to #4000 finishing, followed by mechanical polishing with diamond paste. The open circuit potential measurements and anodic polarization curves were obtained in solution of 0.90 wt. % of NaCl and of simulated body fluid (SBF). The results indicated that the ISO 5832-1 stainless steel presented a high resistance to crevice corrosion in simulated body fluid solution but high susceptibility to this form of corrosion in the chloride solution.  


2013 ◽  
Vol 97 ◽  
pp. 162-165 ◽  
Author(s):  
E. Salahinejad ◽  
M.J. Hadianfard ◽  
D.D. Macdonald ◽  
M. Mozafari ◽  
D. Vashaee ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1391
Author(s):  
Hamad F. Alharbi ◽  
Yassir A. Bahri ◽  
El-Sayed M. Sherif

Pure Ti and 85%Ti-15%Zr alloy were sintered in a heat induction high frequency furnace. The corrosion behaviour of Ti and 85%Ti-15%Zr in simulated body fluid (SBF) was studied. The work was achieved using different techniques as the cyclic polarization (PCP), the impedance spectroscopy (EIS), and the change of the potentiostatic current with time (PCT) experiments. The morphology of the surfaces of Ti and Ti-Zr after being corroded in SBF for 72 were investigated by a scanning electron microscope (SEM) and the analysis for the layer formed on that surface was collected via energy dispersive X-ray (EDX). Results depicted that the 15% Zr present within Ti decreases the corrosion via increasing Ti corrosion resistance and minimizing its measured corrosion rate. PCP data proved that the addition of Zr reduced all anodic, cathodic and corrosion currents. EIS results confirmed that Zr has a positive impact on the reduction of corrosion resistance. PCT, SEM, and EDX examinations displayed that both Ti and Ti-Zr alloy don’t show pitting corrosion even after 72 h exposure to SBF.


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