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Microscopic bio‐corrosion evaluations of magnesium surfaces in static and dynamic conditions
Author(s) -
BONTRAGER J.,
MAHAPATRO A.,
GOMES A.S.
Publication year - 2014
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/jmi.12142
Subject(s) - corrosion , materials science , scanning electron microscope , magnesium alloy , metallurgy , composite material , magnesium , shear stress
Summary Biodegradable materials including biodegradable metals are continuously being investigated for the development of next generation cardiovascular stents. Predictive in vitro tests are needed that could evaluate potential materials while simulating in vivo conditions. In this manuscript we report the microscopic bio‐corrosion evaluations of magnesium surfaces in static and dynamic conditions. A corrosion test bench was designed and fabricated and static and dynamic corrosion tests were carried out with samples of magnesium alloy. The fluid wall shear stress equation and the Churchill's friction factor equation were used to calculate the fluid velocity required to generate the desired shear stress on samples in the test bench. Static and dynamic corrosion tests at 24 and 72 h were carried out at 0.88 Pa shear stress mimicking the in vivo shear stress. Microscopic evaluations of the corroded surfaces were carried out by optical, scanning electron microscopy and energy dispersive X‐ray spectroscopy to evaluate the corrosion behaviour and surface properties of the test samples. The surface and interface analysis of magnesium samples post test indicated that dynamic conditions prevented the build‐up of corrosion by‐products on the sample surface and the corrosion mechanism was uniform as compared to static conditions. The use of a masking element to restrict the exposed area of the sample didn't result in increased corrosion at the boundary. Thus, we have demonstrated the feasibility of the designed test bench as a viable method for bio‐corrosion surface analysis under dynamic corrosion conditions for potential biodegradable cardiovascular stent materials.