ASTM F2129-06

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Designation:F2129–06
Standard Test Method for
Conducting Cyclic Potentiodynamic Polarization
Measurements to Determine the Corrosion Susceptibility of
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Small Implant Devices
This standard is issued under the fixed designation F 2129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope G3 PracticeforConventionsApplicabletoElectrochemical
Measurements in Corrosion Testing
1.1 This test method assesses the corrosion susceptibility of
G5 Reference Test Method for Making Potentiostatic and
small, metallic, implant medical devices, or components
Potentiodynamic Anodic Polarization Measurements
thereof, using cyclic (forward and reverse) potentiodynamic
G15 Terminology Relating to Corrosion and Corrosion
polarization. Examples of device types that may be evaluated
Testing
by this test method include, but are not limited to, vascular
G61 Test Method for Conducting Cyclic Potentiodynamic
stents, ureteral stents (Specification F 1828), filters, support
Polarization Measurements for Localized Corrosion Sus-
segments of endovascular grafts, cardiac occluders, aneurysm
ceptibility of Iron-, Nickel-, or Cobalt-Based Alloys
or ligation clips, staples, and so forth.
1.2 This test method is used to assess a device in its final
3. Terminology
form and finish, as it would be implanted. These small devices
3.1 Definitions:
shouldbetestedintheirentirety.Theupperlimitondevicesize
3.1.1 potentiostat,n—aninstrumentforautomaticallymain-
is dictated by the electrical current delivery capability of the
taining an electrode in an electrolyte at a constant potential or
test apparatus (see Section 6). It is assumed that test methods,
controlled potentials with respect to a suitable reference
suchasReferenceTestMethodG5andTestMethodG61have
electrode (see TerminologyG15).
been used for material screening.
3.1.2 potentiodynamic cyclic polarization (forward and re-
1.3 Because of the variety of configurations and sizes of
verse polarization), n—a technique in which the potential of
implants, this test method provides a variety of specimen
the test specimen is controlled and the corrosion current
holder configurations.
measured by a potentiostat. The potential is scanned in the
1.4 This test method is intended for use on implantable
positiveornoble(forward)directionasdefinedinPracticeG3.
devices made from metals with a relatively high resistance to
The potential scan is continued until a predetermined potential
corrosion.
or current density is reached.Typically, the scan is run until the
1.5 This standard does not purport to address all of the
transpassive region is reached, and the specimen no longer
safety concerns, if any, associated with its use. It is the
demonstrates passivity, as defined in PracticeG3. The poten-
responsibility of the user of this standard to establish appro-
tial scan direction then is reversed until the specimen repassi-
priate safety and health practices and determine the applica-
vates or the potential reaches a preset value.
bility of regulatory limitations prior to use.
3.1.3 scan rate, n—the rate at which the controlling voltage
2. Referenced Documents is changed.
2
3.2 Symbols:
2.1 ASTM Standards:
3.2.1 E = Breakdown or Critical Pitting Potential—the
b
D 1193 Specification for Reagent Water
least noble potential at which pitting or crevice corrosion or
F 1828 Specification for Ureteral Stents
both will initiate and propagate as defined in Terminology
G15. An increase in the resistance to pitting corrosion is
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This test method is under the jurisdiction ofASTM Committee F04 on Medical
associated with an increase in E .
b
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
3.2.2 E = Rest Potential—the potential of the working
r
F04.15 on Material Test Methods.
electrode relative to the reference electrode measured under
Current edition approved May 15, 2006. Published May 2006. Originally
approved in 2001. Last previous edition approved in 2004 as F 2129 – 04.
virtual open-circuit conditions (working electrode is not polar-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ized).
contactASTM Customer Service at service@astm.org. ForAnnual Book ofASTM
3.2.3 E = Zero Current Potential—the potential at which
zc
Standards volume information, refer to the standard’s Document Summary page on
the current reaches a minimum during the forward scan.
the ASTM website.
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F2129–06
3.2.4 E = Fina
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