Effect of fetal calf serum on the corrosion behaviour of magnesium alloys
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In: Materials Science and Engineering: B, Vol. 176, No. 20, 15.12.2011, p. 1746-1755.
Research output: Journal contributions › Journal articles › Research › peer-review
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TY - JOUR
T1 - Effect of fetal calf serum on the corrosion behaviour of magnesium alloys
AU - Hornberger, H.
AU - Witte, F.
AU - Hort, N.
AU - Mueller, W. D.
PY - 2011/12/15
Y1 - 2011/12/15
N2 - The corrosion behaviour of WE43 magnesium alloys using the mini cell system was studied. Voltammetry and impedance spectroscopy were applied to study on the one hand the effect of microstructure of the working electrode and on the other hand the effect of proteins in the electrolyte. Two types of alloy samples were produced (i) by permanent mould casting and (ii) by gas atomization followed by extrusion. The results showed that the microstructure was strongly influenced by the production process. The extruded samples showed an improved homogeneity of phase distribution compared with cast samples as it was aimed for. Due to increased homogeneity it was expected to find higher corrosion resistance. However, the electrochemical results are contradictory and suggest an additional phase in the extruded microstructure. Using energy dispersive X-ray spectroscopy (EDX) the secondary magnesium rare earths (RE) phase of extruded samples showed differing composition than of cast samples as well as additional oxide phases. After the samples were electrochemically investigated in cell medium with and without fetal calf serum (FCS), an impact of FCS was detected in voltammetry due to the length of the polarisation curve. As the tip of the mini cell in contact with the working electrode is small, developing gases tend to spread on the working electrode and break the contact of liquid to the counter electrode; which results in disrupting the current flow. This effect was more pronounced when rising the voltage and was found reduced when using electrolytes with FCS. Impedance spectra were slightly deformed by FCS, seen as a kinetic effect but not as a basic differing corrosion reaction. The insight into the effects of FCS was provided by the mini cell system as this system enables to collect entire series of measurements. In contrast of two single measurements, those series reflected the slight difference caused by FCS. The focus of the electrochemical corrosion study was set on the first half hour of immersion.
AB - The corrosion behaviour of WE43 magnesium alloys using the mini cell system was studied. Voltammetry and impedance spectroscopy were applied to study on the one hand the effect of microstructure of the working electrode and on the other hand the effect of proteins in the electrolyte. Two types of alloy samples were produced (i) by permanent mould casting and (ii) by gas atomization followed by extrusion. The results showed that the microstructure was strongly influenced by the production process. The extruded samples showed an improved homogeneity of phase distribution compared with cast samples as it was aimed for. Due to increased homogeneity it was expected to find higher corrosion resistance. However, the electrochemical results are contradictory and suggest an additional phase in the extruded microstructure. Using energy dispersive X-ray spectroscopy (EDX) the secondary magnesium rare earths (RE) phase of extruded samples showed differing composition than of cast samples as well as additional oxide phases. After the samples were electrochemically investigated in cell medium with and without fetal calf serum (FCS), an impact of FCS was detected in voltammetry due to the length of the polarisation curve. As the tip of the mini cell in contact with the working electrode is small, developing gases tend to spread on the working electrode and break the contact of liquid to the counter electrode; which results in disrupting the current flow. This effect was more pronounced when rising the voltage and was found reduced when using electrolytes with FCS. Impedance spectra were slightly deformed by FCS, seen as a kinetic effect but not as a basic differing corrosion reaction. The insight into the effects of FCS was provided by the mini cell system as this system enables to collect entire series of measurements. In contrast of two single measurements, those series reflected the slight difference caused by FCS. The focus of the electrochemical corrosion study was set on the first half hour of immersion.
KW - Corrosion
KW - Impedance
KW - Magnesium
KW - Polarization
KW - Proteins
KW - Reproducibility
KW - Engineering
UR - http://www.scopus.com/inward/record.url?scp=81155162538&partnerID=8YFLogxK
U2 - 10.1016/j.mseb.2011.07.018
DO - 10.1016/j.mseb.2011.07.018
M3 - Journal articles
AN - SCOPUS:81155162538
VL - 176
SP - 1746
EP - 1755
JO - Materials Science and Engineering: B
JF - Materials Science and Engineering: B
SN - 0921-5107
IS - 20
ER -