1、Designation: F 1044 05Standard Test Method forShear Testing of Calcium Phosphate Coatings and MetallicCoatings1This standard is issued under the fixed designation F 1044; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers shear testing of continuouscalcium phosphate coatings and metallic coatings adhering todense
3、metal substrates at ambient temperatures. It assesses thedegree of adhesion of coatings to substrates, or the internalcohesion of a coating in shear, parallel to the surface plane.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for information
4、only.1.3 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter
5、-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE8 Test Methods for Tension Testing of Metallic Materials3. Terminology3.1 Definit
6、ionsTerminology E6 shall be considered asapplying to the terms used in this test method.4. Summary of Test Method4.1 Shear Method for Calcium Phosphate or Metallic Coat-ings:4.1.1 This test method consists of subjecting a specimenassembly composed of one coated and one uncoated compo-nent to a shear
7、 load. The components to be tested may bebonded together directly by thermomechanical means (forexample, sintering or diffusion bonding) or may be bondedtogether by use of a polymeric adhesive. The adhesive may bein film form or bulk form, but it must have a minimum bulkshear strength of 34.5 MPa (5
8、000 psi) or as great as theminimum required adhesion or cohesion strength of the coat-ing, whichever is greater.4.1.2 The shear load must be applied parallel to the plane ofthe coating utilizing a tensile machine, which is capable ofdetermining the maximum strength of the coating or coatingattachmen
9、t to the substrate interface.4.2 Shear Method for Metallic Coatings OnlyThe lapshear method consists of subjecting a porous coated area tosingle shear loading, generally utilizing suitable polymericadhesive or bone cement adhesive and test jig in a tensionmachine, and determining the maximum shear s
10、tress requiredto obtain separation (that is, the shear strength of the coating/substrate bond or shear strength of the coating).5. Significance and Use5.1 The shear test method is recommended for shear testingof calcium phosphate and metallic/substrate combinations andcan provide information on the
11、adhesive or cohesive strengthof coatings under a uniaxial shear stress.5.2 The test method may be useful for comparative evalu-ation of adhesive or cohesive strengths of a variety of types ofcoatings. Information developed using this test method may beuseful for certain quality control and design pu
12、rposes.5.3 The test method should not be considered to provide anintrinsic values for utilization directly in making calculationssuch as determining the ability of a coating to withstandspecified environmental stresses.5.4 Processing variables, such as substrate preparation priorto coating, surface
13、texture, coating technique variables orpost-coating heat treatment, or heat may introduce a significanteffect on the results of the shear test. The specimen beingevaluated must be representative of the actual end-use coating.6. Apparatus6.1 Testing MachinesMachines used for testing shallconform to t
14、he requirements of Practices E4. The loads used indetermining shear strength and yield strength shall be within1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Method
15、s.Current edition approved April 1, 2005. Published April 2005. Originallyapproved in 1999. Last previous edition approved in 1999 as F 1044 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards v
16、olume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the loading range of the testing machine as defined in PracticesE4. See also Test Methods E8.6.2 Gripp
17、ing Devices:6.2.1 GeneralVarious types of grips may be used totransmit the load applied to the specimens by the testingmachine. To ensure axial shear stress, it is important that thespecimen axis coincide with the centerline of the heads of thetesting machine and that the coating test plane be paral
18、lel to theaxial load. Any departure from this requirement (that is, anyeccentric loading) will introduce bending stresses that are notincluded in the usual stress calculation (force/cross-sectionalarea).6.2.2 Aligned Interface Method for Calcium Phosphate orMetallic Coatings:6.2.2.1 A drawing of a t
19、ypical gripping device for the testassembly is shown in Fig. 1.6.2.2.2 A drawing of the adapter to mate the shear fixture tothe tensile machine is shown in Fig. 2.6.2.2.3 A schematic of the test assembly is shown in Fig. 3.6.2.3 Lap Shear Method for Metallic Coatings Only:6.2.3.1 Lap Shear Testing B
20、onding FixtureA bondingfixture of the type shown in Fig. 4 or equivalent shall bedesigned and machined with sufficient precision to minimizemovement of the specimen during curing of the adhesive.Some coatings, such as porous fiber metal coatings, may bebonded by sintering without the use of this fix
21、ture.6.2.3.2 Lap Shear Test Loading GripsA loading jig of thetype shown in Fig. 5 or equivalent shall be used. It shall bemade of hardened steel having a hardness of not less thanRockwell C60. To minimize the possible effect of distortion ofthe device under load, fitted and machined steel bolts may
22、beused to hold the components together. The interfaces betweenthe tongue and clevises shall be smooth.7. Adhesive Bonding Materials7.1 Adhesive Bonding AgentA polymeric adhesive bond-ing agent in film form, or filled viscous adhesive cement, whenused, shall be identified and shall meet the following
23、 require-ments:7.1.1 The bonding agent shall be capable of bonding thecoating on the test specimen components with an adhesiveshear strength that is at least 34.5 MPa (5000 psi) or as great asthe minimum required adhesion or cohesion strength of thecoating, whichever is greater.7.1.2 In instances wh
24、ere porosity extends to the coating/substrate interface, the bonding agent shall be sufficientlyviscous and application to the coating sufficiently careful toassure that it will not penetrate through the coating to thesubstrate. The FM 1000 Adhesive Film3with a thickness of0.25 mm (0.01 in.) has pro
25、ven satisfactory for this test.7.1.3 If a material other than FM 1000 is used, or thecondition of the FM 1000 is unknown, it must be tested toestablish its equivalence to fresh FM 1000. Testing should beperformed without the presence of the calcium phosphatecoating to establish the performance of th
26、e adhesive.3The sole source of supply of the apparatus known to the committee at this timeis Cytec Engineered Materials, Inc., 1300 Revolution St., Havre de Grace, MD21078. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments wil
27、l receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.FIG. 1 Gripping Device for Shear TestingFIG. 2 Adapter to Mate the Gripping Device to the TensileMachineF10440528. Test Specimen8.1 General:8.1.1 In order to ensure precision and accuracy in te
28、stresults, it is important that care be exercised in the preparationof specimens, both in machining and in the case of multi-partspecimens, in the assembly. Specimen components must beproperly aligned in order that generated stresses be purelyaxial, that is, parallel to the coated surface.8.1.2 Alig
29、ned Interface Method SpecimenThis shear testspecimen is illustrated in Fig. 6. A complete, assembled testassembly consists of two solid pieces; one with a coatedsurface and the other with an uncoated surface. The uncoatedsurface may be roughened to aid in the bonding of theadhesive.8.1.2.1 The cross
30、-sectional area of the substrate upon whichthe coating is applied shall be nominal 2.84 cm2(0.44 in.2).When specimens of another cross-sectional area are used, thedata must be demonstrated to be equivalent to 2.84 cm2standard cross-sectional area and the specimen size should bereported.8.1.3 Lap She
31、ar SpecimenLap shear specimens shallconsist of substrate plates of the type shown in Fig. 7 orequivalent. The dimensions of test specimens differing fromFig. 7 shall be included in the report.8.1.3.1 Test Specimen PositioningThe specimen shall bepositioned in the loading grips so as to cause the loa
32、d axis tobe coincident with the plane of the adhesive. This may beaccomplished by suitably shimming the specimen within thegrips.8.2 Specimen Coating Preparation:8.2.1 Coatings may be applied by any one of a number oftechniques. All test specimens for coating characterizationshall be prepared from i
33、ndicative coating lots, using productionFIG. 3 Drawing of the Recommended Shear Test SpecimenAssemblyFIG. 4 Lap Shear Bonding FixtureFIG. 5 Lap Shear Loading GripsFIG. 6 Aligned Interface SpecimenF1044053feedstock lots and be coated on the same equipment used foractual implants. The coating should c
34、onsist of a layer which ismechanically or chemically attached and covers the surface.8.2.2 All thermal treatments normally performed on thedevices should be performed on the test specimens.8.2.3 If employed, passivation and sterilization techniquesshould be consistent with those used for actual devi
35、ces.8.2.3.1 If the passivation and sterilization processes can beshown not to influence the shear strength, these steps may beeliminated.8.2.4 InspectionBefore testing, visual inspections shouldbe performed on 100 % of the test specimens. Lack of coatingin highly stressed regions, as well as nonunif
36、orm coatingappearance, shall be cause for specimen rejection.8.2.4.1 Coating Thickness MeasurementThe dimensionsof the coating planar surface shall be measured to the nearest0.80 mm (132 in.). For lap shear specimens, the thicknessshould be measured at the center and all four corners of thecoated ar
37、ea to 0.03 mm (0.001 in.). Coating thickness may notvary by more than 615 % of the thickness at the center.9. Procedure9.1 Prepare a minimum of five test specimens and apply thecoating of interest to the face of each in the same manner as foractual production devices.9.2 FM1000 Glue CuringThe test r
38、esults achieved aregreatly dependent upon the adhesive used and the way in whichit is cured. One suggested adhesive commonly used withcalcium phosphate coatings is FM 1000 having a thickness of0.25 mm (0.01 in.). This material has successfully been curedusing the following cycle:9.2.1 Align the adhe
39、sive with the surface of the coating,taking precautions to align the adhesive in the center of thecoating.9.2.2 Apply a constant force using a calibrated high tem-perature spring, resulting in a stress of 0.138 MPa (20 psi)between the coating and the opposing device that will test thecoating.9.2.2.1
40、 Maintain alignment of the coating and the matchingcounterface during the curing of the adhesive.9.2.3 Place the assembly in an oven and heat at 176C(350F) for 2 to 3 h.9.2.3.1 The exact amount of time necessary to cure theadhesive will need to be determined by each user, as oventemperature may vary
41、 with load size and oven type. It issuggested that initially the curing cycle be optimized withoutthe coating present.9.2.4 Remove the cured assembly from the oven and allowit to cool to room temperature.9.2.5 Remove all excess glue which has protruded from thecoated surface without compromising the
42、 integrity of thesample.9.3 3M Scotch - Weld 2214 - NMF Structural AdhesiveGluing Procedure:9.3.1 Ensure that surface to be bonded is clean, degreased,and free of any loose particles and beads.9.3.2 Apply a thin layer of the adhesive evenly to the coatedsurface of the test coupons. A spatula or tong
43、ue depressor maybe used as an application device.9.3.3 Squeeze excess adhesive out of the assembly usinghand pressure while coated faces of the test coupons are buttedtogether.9.3.4 Place the specimen thus prepared in the fixture shownin Fig. 5. During curing, ensure that the fixture maintains amild
44、 pressure at the joint, and force bonding faces to remainparallel and maintain the axial alignment.9.4 Direct Thermomechanical FabricationMetallic coat-ing specimens may be tested in either the aligned interface orsingle lap configuration. For sintered or diffusion bondedcoating systems, the test sp
45、ecimen configurations indicated inFigs. 4-7 may be constructed in a single process with thecoating application without the use of adhesive. The details ofthe specimen fabrication process will necessarily be unique toeach coating system. Perform appropriate inspections to ensurethat the microstructur
46、e and morphology of the coating in thetest specimen configuration are representative of finish produc-tion parts (see 8.2).9.5 Aligned Interface Test:9.5.1 Place the specimen assembly in the grips so that thelong axis of the specimen is perpendicular to the direction ofapplied shear load through the
47、 centerline of the grip assembly.9.5.2 Apply a shear load to each test specimen at a constantrate of cross-head speed of 0.25 cm/min (0.1 in./min). Continuethe test until complete separation of the components has beenachieved. Record the maximum load applied.9.6 Lap Shear Test:9.6.1 Following curing
48、, place the specimen in the testassembly shown in Fig. 6.9.6.2 Load the specimens at a constant rate of cross-headspeed of 0.25 cm/min (0.1 in./min). Continue the test untilcomplete separation of the components has been achieved.Record the maximum load applied.FIG. 7 Lap Shear Specimen (Metal Coatin
49、gs Only)F10440549.7 Discard specimens for which the adhesive has pen-etrated to the substrate and do not include the results in theanalysis and report.10. Stress Calculation10.1 Calculate the substrate area upon which the coating isapplied to the nearest 0.06 cm2(0.01 in.2). Record peak(failure) load and calculate failing stress in MPa (psi) ofadhesive bond area, as follows:S 5 F/A (1)where:S = adhesion or cohesion strength,F = maximum load to failure, andA = cross-sectional area.11. Report11.1 Report the following information:11.1.1 Identification of the materials
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