ASTM F1160-00
(Test Method)Standard Test Method for Shear and Bending Fatigue Testing of Calcium Phosphate and Metallic Medical and Composite Calcium Phosphate/Metallic Coatings
Standard Test Method for Shear and Bending Fatigue Testing of Calcium Phosphate and Metallic Medical and Composite Calcium Phosphate/Metallic Coatings
SCOPE
1.1 This test method covers the procedure for determining the shear and bending fatigue performance of calcium phosphate coatings and of porous and nonporous metallic coatings and for determining the bending fatigue performance of metallic coatings oversprayed with calcium phosphate. This test method has been established based on plasma-sprayed titanium and plasma-sprayed hydroxylapatite coatings. The efficacy of this test method for other coatings has not been established. In the shear fatigue mode this test method evaluates the adhesive and cohesive properties of the coating on a metallic substrate. In the bending fatigue mode this test method evaluates both the adhesion of the coating as well as the effects that the coating may have on the substrate material. These methods are limited to testing in air at ambient temperature. These test methods are not intended for application in fatigue tests of components or devices; however, the test method which most closely replicates the actual loading configuration is preferred.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 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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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: F 1160 – 00
Standard Test Method for
Shear and Bending Fatigue Testing of Calcium Phosphate
and Metallic Medical and Composite Calcium Phosphate/
Metallic Coatings
This standard is issued under the fixed designation F 1160; 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 namic Loads on Displacements in an Axial Load Fatigue
Testing Machine
1.1 This test method covers the procedure for the perfor-
E 468 Practice for Presentation of Constant Amplitude Fa-
mance of calcium phosphate Ca/P and porous and non-porous
tigue Test Results for Metallic Materials
coated metallic coatings in shear and bending fatigue modes
E 1012 Practice for Verification of Specimen Alignment
and composite coatings of calcium phosphate/metal in the
Under Tensile Loading
bending fatigue mode. This test method has been established
based on plasma-sprayed titanium and plasma-sprayed hy-
3. Definitions
droxylapatite coatings. The efficacy of this test method for
3.1 The definitions of terms relating to shear and fatigue
other coatings has not been established. In the shear fatigue
testing appearing in Terminology E 6 shall be considered as
mode this test method evaluates the adhesive and cohesive
applying to the terms used in this test method.
properties of the coating on a metallic substrate. In the bending
fatigue mode this test method evaluates both the adhesion of
4. Summary of Test Method
the coating as well as the effects that the coating may have on
4.1 Shear Fatigue Testing:
the substrate material. These methods are limited to testing in
4.1.1 The intent of the shear fatigue test is to determine the
air at ambient temperature. These test methods are not intended
adhesive or cohesive strength, or both, of the coating.
for application in fatigue tests of components or devices;
4.1.2 This test method is designed to allow the coating to
however, the test method which most closely replicates the
fail at either the coating/substrate interface, within the coating,
actual loading configuration is preferred.
or at the glue/coating interface between the coating and the
1.2 The values stated in SI units are to be regarded as the
adhesive bonding agent used to transmit the load to the coating.
standard.
4.2 Bending Fatigue Testing:
1.3 This standard does not purport to address all of the
4.2.1 The primary intent of the bending fatigue test is to
safety concerns, if any, associated with its use. It is the
quantify the effect that the coating has on the substrate it is
responsibility of the user of this standard to establish appro-
applied to. Secondarily, it may be used to provide a subjective
priate safety and health practices and determine the applica-
evaluation of coating adhesion, (that is, spalling resistance,
bility of regulatory limitations prior to use.
cracking resistance, and so forth).
2. Referenced Documents 4.2.2 This test is designed to first provide a substrate fatigue
strength to serve as a baseline to assess the effects of the
2.1 ASTM Standards:
coating on the resulting fatigue strength of the system.
E 6 Terminology Relating to Methods of Mechanical Test-
ing
5. Significance and Use
E 206 Definitions of Terms Relating to Fatigue Testing and
3 5.1 The shear and bending fatigue tests are used to deter-
the Statistical Analysis of Fatigue Data
mine the effect of variations in material, geometry, surface
E 466 Practice for Conducting Force Controlled Constant
2 condition, stress, and so forth, on the fatigue resistance of
Amplitude Axial Fatigue Tests of Metallic Materials
coated metallic materials subjected to direct stress for up to 10
E 467 Practice for Verification of Constant Amplitude Dy-
cycles. These tests may be used as a relative guide to the
selection of coated materials for service under condition of
This test method is under the jurisdiction of ASTM Committee F04 on Medical
repeated stress.
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
5.2 In order that such basic fatigue data be comparable,
F04.15 on Materials Test Methods.
reproducible, and can be correlated among laboratories, it is
Current edition approved Nov. 10, 2000. Published January 2001. Originally
published as F 1160 – 91. Last previous edition F 1160 – 98.
essential that uniform fatigue practices be established.
Annual Book of ASTM Standards, Vol 03.01.
5.3 The results of the fatigue test may be used for basic
Discontinued 1988, see Annual Book of ASTM Standards, Vol 03.01; replaced
material property design. Actual components should not be
by Terminology E 1823.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F 1160
tested using these test methods.
6. Equipment Characteristics
6.1 Equipment characteristics shall be in accordance with
Practice E 466, Section 7.
6.2 Shear Fatigue Test Grips:
6.2.1 General—Various types of grips may be used to
transmit the load to the specimens by the testing machine. To
ensure axial shear stress, it is important that the specimen axis
coincide with the centerline of the heads of the testing machine
and that the coating test plane be parallel to the axial load. Any
departure from this requirement (that is, any eccentric loading)
will introduce bending stresses that are not included in the
usual stress calculation (force/cross-sectional area).
6.2.2 A drawing of a typical gripping device for the test
assembly is shown in Fig. 1.
6.2.3 Fig. 2 shows a drawing of the adaptor to mate the
shear fixture to the tensile machine
6.2.4 Figs. 3 and 4 show a schematics of the test setup.
6.3 Bending Fatigue Test Grips—There are a variety of
testing machines that may be employed for this test (that is,
FIG. 2 Adaptor to Mate the Gripping Device to the Tensile
rotating beam fatigue machines and axial fatigue machines). Machine
The gripping method for each type of equipment shall be
determined by either the manufacturer of that equipment
(rotating beam machines) or the user.
7. Adhesive Bonding Materials
7.1 Adhesive Bonding Agent—A polymeric adhesive bond-
ing agent in film form, or filled viscous adhesive cement, shall
be identified and shall meet the following requirements.
FIG. 3 Schematic of the Shear Test Setup
7.1.1 The bonding agent shall be capable of bonding the
coating on the test specimen components with an adhesive
shear strength that is at least 34.5 MPa.(5000 psi) or as great as to the substrate. The FM 1000 Adhesive Film with a thickness
the minimum required adhesion or cohesion strength of the of 0.25 mm (0.01 in.) has proven satisfactory for this test.
coating, whichever is greater.
7.1.3 If a material other than FM 1000 is used, or the
condition of the FM 1000 is unknown, it must be tested to
7.1.2 In instances where coating porosity extends to the
establish its equivalence to fresh FM 1000. Testing should be
coating/substrate interface, the bonding agent shall be suffi-
performed without the presence of the coating to establish the
ciently viscous and application to the coating sufficiently
performance of the adhesive.
detailed, to ensure that it will not penetrate through the coating
8. Test Specimen
8.1 Shear Fatigue Specimen for Ca/P and metallic coatings
only:
8.1.1 The recommended shear test specimen and setup is
illustrated in Figs. 3 and 4, respectively. A complete assembled
test assembly consists of two solid pieces, one with a coated
surface and the other with an uncoated surface. The uncoated
surface may be roughened to aid in the adhesion of the
adhesive bonding agent.
8.1.2 The cross-sectional area of the substrate upon which
2 2
the coating is applied shall be a nominal 2.85 cm (0.44 in. ).
When specimens of another cross-sectional area are used, the
data must be demonstrated to be equivalent to the results
produced using the 2.85-cm standard cross-sectional area and
the specimen size should be reported.
FIG. 1 Gripping Device for Shear Testing Available from Cytec, Harve de Grace, MD.
F 1160
FIG. 6 Specimens With a Continuous Radius Between the Ends
for Rotating Beam or Axial loading
FIG. 7 Specimens With Tangentially Blending Fillets Between the
Uniform Test Section and the Ends for Axial Loading
FIG. 8 Specimens With a Continuous Radius Between the Ends
FIG. 4 Drawing of the Recommended Shear Test Specimen
for Axial Loading
Assembly
be applied to the 19.05-mm (0.75-in.) diameter face only (see
8.2 Bending Fatigue Specimen for Ca/P, metallic, and
Fig. 3)
Ca/P-metallic composite coatings:
8.3.2.2 For the bending fatigue specimens, the coating
8.2.1 The type of specimen used will depend upon the
should be applied to the reduced section only, with the
objective of the test program, the type of equipment, the
exception of the constant stress specimen which should have
equipment capacity, and the form in which the material is
coating in the entire region of constant stress (see Figs. 5-9).
available. However, the design must meet certain general
8.3.3 All thermal treatments normally performed on the
criteria as follows:
devices should be performed on the test specimens.
8.2.1.1 The design of the specimen should be such that if
8.3.4 If employed, passivation and sterilization techniques
specimen failure should occur, it should occur in the test
should be consistent with those used for actual devices.
section (reduced area as shown in Figs. 5-8).
8.3.5 Inspection—Before testing, visual inspections should
8.2.1.2 Specimens employing a flat tapered beam configu-
be performed on 100 % of the test specimens. Nonuniform
ration should be designed such that a constant surface stress
coating density shall be cause for specimen rejection. For the
exists in the test section when the specimen is constrained at
shear fatigue specimen, lack of coating on the coated face shall
one end and point loaded perpendicular to the beam axis at the
be cause for specimen rejection. For the bending fatigue
other end (that is, cantilever loading).
specimen, lack of coating in highly stressed regions shall be
8.2.1.3 Rotating beam specimens may have unique dimen-
cause for specimen rejection.
sions, depending upon the type of machine used. Appropriate
manufacturers’ specifications for these specimens should be
9. Procedure
used.
9.1 The number of specimens required for testing, as well as
8.3 Specimen Coating Preparation:
the test methods in which the fatigue data may be interpreted,
8.3.1 Coatings may be applied by any one of a number of
can vary. Several test methods are referenced in this test
techniques. All test specimens for coating characterization
5 ,6,7
method.
shall be prepared from indicative coating lots, using production
feedstock lots and be coated on the same equipment used for
actual implants. The coating should consist of a layer which is
Collins, J.A., Failure of Materials in Mechanical Design, John Wiley & Sons,
mechanically or chemically attached and covers the surface.
New York, 1981.
Handbook of Fatigue Testing, ASTM STP 566, ASTM, 1974.
8.3.2 Coatings should be applied as follows:
8.3.2.1 For the shear fatigue specimens, the coating should
FIG. 5 Bending Fatigue Specimen With Tangentially Blending
Fillets Between the Test Section and the Ends for Rotating Beam
or Axial Loading FIG. 9 Tapered Beam Configuration for Bend Testing
F 1160
9.2 The type of specimen used will depend upon the 9.5.3 For the rotating beam test, do not apply the load until
objective of the test program, the type of equipment available, the machine is operating at the frequency desired for testing.
the equipment capacity, and the form in which the material is 9.5.4 For the purpose of calculating the applied loads on the
available. The specimen chosen should come as close to test specimen, to determine the applied stresses, measure the
matching the intended application as possible. dimensions from which the substrate area is calculated to the
9.3 The test frequency employed shall not exceed 170 Hz. nearest 0.03 mm (0.001 in.) for dimensions equal to or greater
9.4 Shear Fatigue Specimens: than 5.08 mm (0.200 in.) and to the nearest 0.013 mm (0.0005
9.4.1 Curing the Adhesive—The test results achieved are in.) for dimensions less than 5.08 mm (0.002 in.).
greatly dependent upon the adhesive used and the way in which 9.5.4.1 For the coated specimens, the uncoated substrate
it is cured. One suggested adhesive is FM 1000 having a dimensions should be used to calculate the applied stress.
thickness of 0.25 mm (0.01 in.). This material has successfully 9.5.5 Any fracture which occurs outside the gage section
been cured using the following cycle: shall be rejected.
9.4.1.1 Align the adhesive with the surface of the coating,
10. Test Termination
taking precautions to align the adhesive in the center of the
coating. 10.1 Continue the testing until the specimen fails or until a
predetermined number of cycles has been reached (typically 10
9.4.1.2 Apply a constant force using a calibrated high
temperature spring, resulting in a stress of 0.138 MPa (20 psi) 7 cycles). Failure may be defined as: (1) complete separation of
the coating, (2) visible cracking at a specified magnification,
between the coating and the opposing device that will test the
coating. (3) a crack of certain dimensions, (4) or by some other
9.4.1.2.1 Care must be taken to maintain alignment of the criterion.
coating and the matching counterface during the test.
11. Stress Calculation
9.4.1.3 Place the assembly in an oven and heat at 176°C for
11.1 Shear Fatigue Specimens—Calculate the substrate area
2to3h.
upon which the coating is applied to the nearest 0.06 cm (0.01
9.4.1.3.1 The exact amount of time necessary to cure the
in. ). Record peak (failure) load and calculate failing stress in
adhesive will need to be determined by each user, as oven
megapascals (pound-force per square inch) of adhesive area as
temperature may vary with load size and oven type. It is
follows:
suggested that the curing cycle be optimized first without the
Adhesion or cohesion strength = maximum load/cross-
coating present.
sectional area
9.4.1.4 Remove the cured assembly from the oven and
11.2 Bending Fatigue Specimens—For the purpose of cal-
allow it to cool to room temperature.
culating the applied loads on the test specimen to determine the
9.4.1.5 Remove all excess adhesive which has protruded
applied stresses, measure the dimensions from which the
from the coated surface. This process must not compromise the
su
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