ASTM F746-04(2014)

Standard Test Method for Pitting or Crevice Corrosion of Metallic Surgical Implant Materials

SIGNIFICANCE AND USE
4.1 This test method is designed solely for determining comparative laboratory indices of performance. The results may be used for ranking alloys in order of increasing resistance to pitting and crevice corrosion under the specific conditions of this method. It should be noted that the method is intentionally designed to reach conditions that are sufficiently severe to cause breakdown of at least one alloy (Type 316 L stainless steel) currently considered acceptable for surgical implant use, and that those alloys which suffer pitting or crevice corrosion during the more severe portions of the test do not necessarily suffer localized corrosion when placed within the human body as a surgical implant.
SCOPE
1.1 This test method covers the determination of resistance to either pitting or crevice corrosion of metals and alloys from which surgical implants will be produced. It is a modified version of an established test2 and is used as a screening test to rank surgical implant alloys in order of their resistance to localized corrosion.  
1.2 This test method applies only to passive metals and alloys. Nonpassive alloys (other than noble alloys) are susceptible to general corrosion and are not normally suitable for implant use.  
1.3 This test method is intended for use as a laboratory screening test for metals and alloys which undergo pitting or crevice corrosion, or both.  
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2014
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.15 - Material Test Methods

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F746 − 04 (Reapproved 2014)
Standard Test Method for
Pitting or Crevice Corrosion of Metallic Surgical Implant
1
Materials
ThisstandardisissuedunderthefixeddesignationF746;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope F2129Test Method for Conducting Cyclic Potentiodynamic
Polarization Measurements to Determine the Corrosion
1.1 This test method covers the determination of resistance
Susceptibility of Small Implant Devices
to either pitting or crevice corrosion of metals and alloys from
G3Practice for Conventions Applicable to Electrochemical
which surgical implants will be produced. It is a modified
2 Measurements in Corrosion Testing
versionofanestablishedtest andisusedasascreeningtestto
G5Reference Test Method for Making Potentiodynamic
rank surgical implant alloys in order of their resistance to
Anodic Polarization Measurements
localized corrosion.
G15TerminologyRelatingtoCorrosionandCorrosionTest-
1.2 This test method applies only to passive metals and 4
ing (Withdrawn 2010)
alloys. Nonpassive alloys (other than noble alloys) are suscep-
3. Summary of Test Method
tible to general corrosion and are not normally suitable for
implant use.
3.1 Acylindricalspecimenfittedwithaninerttaperedcollar
is immersed in a phosphate buffered saline electrolyte at 37°C
1.3 This test method is intended for use as a laboratory
for1hto establish a corrosion potential. Pitting (or crevice
screening test for metals and alloys which undergo pitting or
corrosion) is then stimulated by potentiostatically polarizing
crevice corrosion, or both.
thespecimentoapotentialmuchmorenoblethanthecorrosion
1.4 The values stated in either SI units or inch-pound units
potential. Stimulation of pitting (or crevice corrosion) will be
are to be regarded separately as standard. The values stated in
marked by a large and generally increasing polarizing current.
each system may not be exact equivalents; therefore, each
3.2 Immediately after the stimulation step, the potential is
system shall be used independently of the other. Combining
decreased as rapidly as possible to one of several preselected
values from the two systems may result in non-conformance
potentials at, or more noble than, the corrosion potential. If the
with the standard.
alloy is susceptible to pitting (or crevice corrosion) at the
1.5 This standard does not purport to address all of the
preselected potential, the polarizing current will remain at
safety concerns, if any, associated with its use. It is the
relatively high values and will fluctuate or increase with time.
responsibility of the user of this standard to establish appro-
A post-test examination of the metal specimen establishes
priate safety and health practices and determine the applica-
whether localized corrosion has occurred by pitting of the
bility of regulatory limitations prior to use.
exposed surface or by preferential attack at the crevice formed
by the tapered collar, or both.
2. Referenced Documents
3 3.3 If the pit (or crevice) surface repassivates at the pre-
2.1 ASTM Standards:
selected potential and localized corrosion is halted, the polar-
D1193Specification for Reagent Water
izing current will drop to values typical for passive surfaces
F86Practice for Surface Preparation and Marking of Metal-
and the current will decrease continuously. The parameter of
lic Surgical Implants
interest, the critical potential for pitting (or crevice corrosion),
is defined as the highest (most noble) pre-selected potential at
1
ThistestmethodisunderthejurisdictionofASTMCommitteeF04onMedical
whichpit(orcrevice)surfacesrepassivateafterthestimulation
andSurgicalMaterialsandDevicesandisthedirectresponsibilityofSubcommittee
step.
F04.15 on Material Test Methods.
Current edition approved Oct. 1, 2014. Published November 2014. Originally
4. Significance and Use
ε1
approved in 1981. Last previous edition approved in 2009 as F746–04(2009) .
DOI: 10.1520/F0746-04R14.
4.1 This test method is designed solely for determining
2
Syrett, B. C., Corrosion, Vol 33, 1977, p. 221.
comparative laboratory indices of performance. The results
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F746 − 0
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: F746 − 04 (Reapproved 2009) F746 − 04 (Reapproved 2014)
Standard Test Method for
Pitting or Crevice Corrosion of Metallic Surgical Implant
1
Materials
This standard is issued under the fixed designation F746; 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 (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Units information was editorially corrected in January 2010.
1. Scope
1.1 This test method covers the determination of resistance to either pitting or crevice corrosion of metals and alloys from which
2
surgical implants will be produced. It is a modified version of an established test and is used as a screening test to rank surgical
implant alloys in order of their resistance to localized corrosion.
1.2 This test method applies only to passive metals and alloys. Nonpassive alloys (other than noble alloys) are susceptible to
general corrosion and are not normally suitable for implant use.
1.3 This test method is intended for use as a laboratory screening test for metals and alloys which undergo pitting or crevice
corrosion, or both.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
3
2.1 ASTM Standards:
D1193 Specification for Reagent Water
F86 Practice for Surface Preparation and Marking of Metallic Surgical Implants
F2129 Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements to Determine the Corrosion Suscepti-
bility of Small Implant Devices
G3 Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing
G5 Reference Test Method for Making Potentiodynamic Anodic Polarization Measurements
4
G15 Terminology Relating to Corrosion and Corrosion Testing (Withdrawn 2010)
3. Summary of Test Method
3.1 A cylindrical specimen fitted with an inert tapered collar is immersed in a phosphate buffered saline electrolyte at 37°C for
1 h to establish a corrosion potential. Pitting (or crevice corrosion) is then stimulated by potentiostatically polarizing the specimen
to a potential much more noble than the corrosion potential. Stimulation of pitting (or crevice corrosion) will be marked by a large
and generally increasing polarizing current.
3.2 Immediately after the stimulation step, the potential is decreased as rapidly as possible to one of several preselected
potentials at, or more noble than, the corrosion potential. If the alloy is susceptible to pitting (or crevice corrosion) at the
1
This test method is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.15 on Material Test Methods.
Current edition approved Dec. 1, 2009Oct. 1, 2014. Published January 2010November 2014. Originally approved in 1981. Last previous edition approved in 20042009
ε1
as F746 – 04.F746 – 04(2009) . DOI: 10.1520/F0746-04R09E01.10.1520/F0746-04R14.
2
Syrett, B. C., Corrosion, Vol 33, 1977, p. 221.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F746 − 04 (2014)
preselected potential, the polarizing current will remain at relatively high values and will fluctuate or increase with time. A post-test
examination of the metal specimen establishes whether localized corrosion has occurred by pitting of the exposed surface or by
preferential attack at the crevice formed by the tapered collar, or both.
3.3 If the pit (or crevice) surf
...