ASTM F1854-01
(Test Method)Standard Test Method for Stereological Evaluation of Porous Coatings on Medical Implants
Standard Test Method for Stereological Evaluation of Porous Coatings on Medical Implants
SIGNIFICANCE AND USE
These test methods are recommended for elementary quantification of the stereological properties of porous coatings and the solid substrates to which they are bonded.
These test methods may be useful for comparative evaluations of different coatings or different lots of the same coating.
All three methods should be performed on the same working surface.
A statistical estimate can be made of the distributions of the mean coating thickness and the volume percent void. No estimate can be made of the distribution of intercept lengths unless the void is a regular geometric shape that can be defined mathematically.
SCOPE
1.1 This test method covers stereological test methods for characterizing the coating thickness, void content, and mean intercept length of various porous coatings adhering to nonporous substrates.
1.2 Porous coatings with significant gradients in the porosity from the substrate to the surface will require use of the alternate sample orientation method outlined in 8.2.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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.
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Designation:F1854–01
Standard Test Method for
Stereological Evaluation of Porous Coatings on Medical
1
Implants
This standard is issued under the fixed designation F 1854; 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 3.1.6 substrate interface—theregionwheretheporouscoat-
ing is attached to the substrate.
1.1 This test method covers stereological test methods for
3.1.7 working surface—the ground and polished face of the
characterizing the coating thickness, void content, and mean
metallographic mount where the measurements are made.
intercept length of various porous coatings adhering to nonpo-
rous substrates.
4. Summary of Test Method
1.2 Porous coatings with significant gradients in the poros-
4.1 Mean Coating Thickness—Measurement grid lines are
ity from the substrate to the surface will require use of the
orientedperpendiculartothesubstrateinterface.Oneachofthe
alternate sample orientation method outlined in 8.2.
lines in the group, the distance from the substrate interface to
1.3 The values stated in SI units are to be regarded as the
the last contact with the porous coating material is measured.
standard.
The average of the line lengths over the group of lines is the
1.4 This standard does not purport to address all of the
local mean coating thickness.
safety concerns, if any, associated with its use. It is the
4.2 Volume Percent Void—A regular grid of points is
responsibility of the user of this standard to establish appro-
superimposed on a field from the working surface. The
priate safety and health practices and determine the applica-
percentage of points that are in contact with void areas in the
bility of regulatory limitations prior to use.
coating correlates with the volume percent of void present.
2. Referenced Documents 4.3 Mean Void Intercept Length—Measurement grid lines
are oriented parallel to the substrate interface. The number of
2.1 ASTM Standards:
2
times the lines intercept voids is used with the volume percent
E 3 Practice for Preparation of Metallographic Specimens
2
void to calculate the mean void intercept length.
E 883 Guide for Reflected Light Photomicrography
5. Significance and Use
3. Terminology
5.1 These test methods are recommended for elementary
3.1 Definitions:
quantificationofthestereologicalpropertiesofporouscoatings
3.1.1 field—the image of a portion of the working surface
and the solid substrates to which they are bonded.
upon which measurements are performed.
5.2 These test methods may be useful for comparative
3.1.2 intercept—the point on a measurement grid line pro-
evaluations of different coatings or different lots of the same
jected on a field where the line crosses from solid to void or
coating.
vice versa.
5.3 All three methods should be performed on the same
3.1.3 measurement grid lines—a evenly spaced grid of
working surface.
parallel lines all of the same length.
5.4 Astatistical estimate can be made of the distributions of
3.1.4 porous coating—coating on an implant deliberately
the mean coating thickness and the volume percent void. No
appliedtocontainvoidregionswiththeintentofenhancingthe
estimate can be made of the distribution of intercept lengths
fixation of the implant.
unless the void is a regular geometric shape that can be defined
3.1.5 substrate—the solid material to which the porous
mathematically.
coating is attached.
6. Apparatus
1
This test method is under the jurisdiction ofASTM Committee F04 on Medical
6.1 The procedures outlined in this test method can be
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
performed manually or by an automated procedure. The
F04.15 on Material Test Methods.
following apparatus are necessary for manual calculations.
Current edition approved October 10, 2001. Published February 2002.
2
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F1854
6.2 Microscope, or other suitable device with a viewing 9. Procedure
screen or photomicrographic capability of at least 125 by 175
9.1 Mean Coating Thickness:
mm should be used to image the working surface.
9.1.1 Appendix X2 includes two sets of typical measure-
6.3 Transparent Sheet, with measurement grid lines or
ment grids each with ten measurement lines, one set separated
points is superimposed on the viewing screen or photomicro-
byadistanceof1cmandonesetseparatedbyadistanceof0.5
graph for the measurements. The grid lines grids of points
cm.
should be unifor
...
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