Stent Corrosion Testing: Measured parameters
- Different potentials : Er (rest potential), Eb (breakdown potential), Ep (protection potential), Ev (vertex potential)
- icor (corrosion current in A)
- rest potential evolution in function of time
- Polarization curves
Stent Corrosion Testing: Scope
- Stent Corrosion Testing
- Corrosion susceptibility of small, metallic, implant medical devices, or components thereof, using cyclic (forward and reverse) potentiodynamic polarization.
- Examples of device types : vascular stents, ureteral stents, filters, support segments of endovascular grafts, cardiac occluders, aneurysm or ligation clips, staples, and so forth
Stent Corrosion Testing: Applicable standards
- ASTM F2129-08: STANDARD TEST METHOD FOR CONDUCTING CYCLIC POTENTIODYNAMIC POLARIZATION MEASUREMENTS TO DETERMINE THE CORROSION SUSCEPTIBILITY OF SMALL IMPLANT DEVICES
Stent Corrosion Testing: Associated tests
- Galvanic Corrosion
- Degradation of metallic implant
- Optical Inspection
- Scanning Electron Microscopy (SEM)
Stent Corrosion Testing: Test Method Description
The device is placed in an appropriate de-aerated simulated physiological solution and the rest potential (Er) is recorded for 1h or, alternatively, until the rest potential stabilizes to a rate of change less than 3mV/min. The potentiodynamic scan is then started at Er and scanned in the positive or noble (forward) direction.
The scan is reversed...
The scan is reversed after either the vertex potential is reached or the current density has reached a value approximately two decades greater than the current density measured at the breakdown potential. The reverse scan is stopped after the current has become less than that in the forward direction or the potential reaches Er. The data is plotted with the current density in mA/cm2 on the x axis (logarithmic axis) versus the potential in mV on the y axis (linear axis). The fluid test is PBS (Phosphate Buffer Saline) or other on demand. The test is performed at 37+/-1°C or other on demand.