1、Designation: F2024 10Standard Practice forX-ray Diffraction Determination of Phase Content of Plasma-Sprayed Hydroxyapatite Coatings1This standard is issued under the fixed designation F2024; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice is for the determination, by the ReferenceIntensity Ratio External Standard Method,
3、 of the percent byweight of the crystalline phases, hydroxyapatite (HA), beta-(whitlockite) tricalcium phosphate (b-TCP), and calcium oxide(CaO) in coatings deposited upon metallic substrates byplasma-spraying hydroxyapatite.1.2 A major component in plasma-sprayed HA coatingsother than HA is expecte
4、d to be amorphous calcium phosphate(ACP). Crystalline components other than HA that may bepresent include alpha- and beta- (whitlockite) tricalcium phos-phates, tetracalcium phosphate (TTCP), calcium oxide, andcalcium pyrophosphates. Quantification of the minor crystal-line components has proven to
5、be very unreliable due toextreme overlap and confounding of X-ray diffraction peaks.Therefore, this practice addresses the quantification of onlyHA, b-TCP, and CaO.1.3 This practice was developed for plasma-sprayed HAcoatings with HA contents of at least 50 % of the total coating.It is recognized th
6、at the analysis of the crystalline componentsuses diffraction from regions of the pattern that also includes asmall contribution from the amorphous component. However,within the limits of applicability of this practice, the effect ofsuch interference is believed to be negligible.1.4 The coating anal
7、yzed shall be produced and processedunder equivalent manufacturing conditions to that on thedevice of interest.1.5 This practice requires the use of monochromated copperKa radiation and flat samples.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are in
8、cluded in thisstandard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
9、 to use.2. Terminology2.1 Definitions:2.1.1 crystalline phases:Chemical and MineralNamesFormula PDF Card No.2whitlockitebeta-tricalcium phosphateb-Ca3(PO4)29-169calcium phosphatealpha-tricalcium phosphatea-Ca3(PO4)29-348limecalcium oxideCaO 37-1497hydroxyapatite(hydroxylapatite)Ca5(PO4)3OH 9-4322.2
10、plasma-sprayed hydroxyapatite coatinga coating,consisting of at least 50 % hydroxyapatite by weight, preparedby plasma-spraying hydroxyapatite on a substrate.3. Significance and Use3.1 Calcium phosphate coatings have been shown in animaland clinical studies to be biocompatible and to enhance theearl
11、y attachment of bone to implant surfaces (see Refs. 1-5)33.2 It is believed that the form of calcium phosphateceramic and its purity with respect to secondary crystallinephases and amorphous material have an effect on its physical,mechanical, and biological properties. However, no definitivestudies
12、of effects on biological properties have been completed.To achieve reproducible clinical results and to permit thedetermination of the effects of properties of the coating onbiological performance, it is essential that the properties ofboth clinical and experimental materials be well-characterizedan
13、d consistent.1This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.13 on Ceramic Materials.Current edition approved June 1, 2010. Published June 2010. Originallyapproved in 2000. Last previous ed
14、ition approved in 2000 as F202400 which waswithdrawn in January 2009 and reinstated in June 2010. DOI: 10.1520/F202410.2Joint Committee on Powder Diffraction Standards, Swarthmore, PA.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM Inte
15、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.3 This practice provides procedures for determination ofthe percentage by weight of the crystalline phases identified ashydroxyapatite, b-TCP and CaO in plasma-sprayed hydroxya-patite coatings.4. Quantit
16、ative Phase Analysis by the External StandardTechnique4.1 The external standard technique allows the determina-tion of weight fractions of individual phases in a mixturecontaining an amorphous fraction by comparison of the inte-grated intensity of one or more peaks from the phase(s) ofinterest to th
17、e external standard under identical instrumentalconditions (6). The sample analyzed may be a solid such as aplasma-sprayed coating or may be a powder. The massabsorption coefficients of the sample and standard must beknown.4.2 The weight fraction of the analyte phase in the mixtureis given by Equati
18、on 11 of Ref (6), as follows:Wi5SIihklIiRELDSxmxsDS1IsPure RIRiD(1)where:Iihkl= integrated intensity of the analyte phase (hkl) peakor sum of peaks,IiREL= relative intensity of the analyte phase (hkl) peak orsum of peaks,xm= mass absorption coefficient of the mixture,xs= mass absorption coefficient
19、of the standard,IsPure= integrated intensity of the most intense peak of thepure standard measured under identical condi-tions, andRIRi= reference intensity ratio of the analyte phase to thestandard.Values of the relative intensities, mass absorption coeffi-cients, and reference intensity ratios whi
20、ch have been mea-sured for HA, b-TCP, and CaO are given in Appendix X1.5. Procedure5.1 Sample Preparation:5.1.1 Plasma sprayed coating samples in the form of flatcoupons of nominal dimensions 2.5 by 2.5 by 0.6 cm may beanalyzed directly on the coated surface. The coating must be atleast 44 m thick t
21、o provide a sample opaque to the X-raybeam. Thinner samples must be removed from the substrateand either deposited in a layer of at least 44-m thickness andarea sufficient to exceed the dimensions of the irradiated area.5.1.2 Reliable quantitative analysis cannot be performed byX-ray diffraction on
22、curved surfaces because of errors causedby absorption and defocusing.5.1.3 Microabsorption caused by variations in either particlesize or surface roughness will produce errors in the measureddiffracted intensity. The effective particle size and variation insurface roughness of the alpha-corundum ext
23、ernal standardmust be less than 5 m.5.2 X-ray Equipment:5.2.1 A standard Bragg-Brentano focusing diffractometerequipped with a pyrolytic graphite monochromator is recom-mended. Because of the need to resolve closely spaced andoverlapping peaks, a diffracted beam monochromator is re-quired unless a s
24、olid-state detector is used. Linearity of theinstrument and associated electronics must be verified dailyprior to utilizing this method. Use of NIST silicon powderstandard, SRM 640 is suggested.45.2.2 An X-ray source with a copper target is required.Characteristic copper radiation provides the neede
25、d X-raydiffraction peak resolution and allows for separation of peaksfrom contaminant phases at a suitable range of diffractionangles from nominally 20 to 60 2u. A 1.0 incident beamdivergence, a 0.2 receiving slit, and soller slits in eitherincident or diffracted beam, or both, are suitable.5.3 X-ra
26、y Method and Data Reduction Strategy:5.3.1 Collect a diffraction pattern from 20 to 60 2u at 0.02increments for a minimum of 1s/point.5.3.2 X-ray diffraction peaks (or peak groups) from thecrystalline phases must be separated in order to quantify theHA content. The following outline provides a data
27、reductionstrategy in order to provide the integrated intensities necessaryto determine the HA, b-TCP, and CaO content of mixtures ofamorphous calcium phosphate, a-TCP, b-TCP, CaO,b-Ca2P2O7, tetracalcium phosphate, and hydroxyapatite. Ac-complish the determination of integrated intensities usingcompu
28、ter techniques, with least-squares fitting of the selectedpeak shape to the experimental data. Manual fitting of peak andbackground is not permitted under this standard practice.5.3.2.1 Obtain the b-TCP content by integration from 30.5to 31.5 2u. The b-TCP peak being used for quantification isthe (0
29、 2 10) peak. This region is integrated by assuming a linearbackground and a Pearson VII functional form of the peakssurrounding the region.5.3.2.2 Determine the calcium oxide content by integrationfrom 37.0 to 38.5 2u and correct for the b-TCP (1 2 11) and(315) peaks. This region contains the 100 %
30、(200) calciumoxide peak, and is integrated by assuming a linear form to thebackground.5.3.2.3 Finally, determine by integration the region from38.5 to 59.0 2u HA and correct for interference by b-TCP andcalcium oxide. A large angular range is used in order to use asmany peaks as possible and to redu
31、ce the effects of preferredorientation. Again, this region is integrated assuming a linearform of the background.5.3.3 Perform the analysis as an external standard techniquewith reference to an alpha-corundum standard, using therelative intensities, mass absorption coefficients, and referenceintensi
32、ty ratios shown in Appendix X1. Reference intensityratios determined experimentally using the equipment andconditions used for analysis of unknown samples may besubstituted for those shown, provided that their validity underthe experimental conditions used for analysis has been verifiedusing known s
33、tandards. An example calculation is shown asAppendix X2.5.3.4 Verify the validity of the analytical procedures appliedusing known mixtures of powders ranging from nominally 50to 95 % hydroxyapatite. Conduct periodic revalidation (at least4Available from National Institute of Standards and Technology
34、 (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.F2024 102annually) of instrument conditions and analytical techniqueusing retained plasma-sprayed hydroxyapatite samples.6. Report6.1 Report following information:6.1.1 Sample identification,6.1.2 Condition of analyze
35、d sample, as-sprayed coating oncoupon or powder spalled from sample,6.1.3 Analytical results expressed as percent hydroxyapa-tite, percent b-TCP, and percent CaO relative to the entiresample,6.1.4 Balance expressed as balance-amorphous calciumphosphate (ACP) and other minor phases, and6.1.5 Statisti
36、cal variability of the results based on thevariability in the RIR values (shown in Table X1.1) andinstrumental conditions.6.2 Further reporting by the device manufacturer shallinclude any treatment applied to the coating after plasma-spraying.7. Precision and Bias7.1 The precision and bias of this p
37、ractice are currentlybeing determined in an interlaboratory test program. Individualexperience indicates that reproducibility is on the order of63 % for determination of the HA content of plasma-sprayedcoatings.8. Keywords8.1 amorphous calcium phosphate (ACP); hydroxyapatitecoatings; hydroxyapatite
38、(HAP); hydroxylapatite coatings;phase analysis; tricalcium phosphate; whitlockiteAPPENDIXES(Nonmandatory Information)X1. REFERENCE VALUES FOR ANALYSISTABLE X1.1 Experimentally Determined Reference IntensityRatios (RIR) Relative to Alpha-Corundum, aAl2O3Phase RIRHydroxyapatite (commercial powder) 1.2
39、76 6 0.001b-TCP 1.146 6 0.004CaO 3.375 6 0.004TABLE X1.2 Combined Relative Intensities for the IntegrationRegions Indicated (6)Phase Range 2u, IRelHydroxyapatite 38.5 - 59.0 2.16 6 0.02b-TCP 30.5 - 31.637.0 - 38.538.5 - 59.01.00 6 0.000.145 6 0.0012.35 6 0.01CaO 37.0 - 38.538.5 - 59.01.00 6 0.001.32
40、 6 0.007F2024 103X2. EXAMPLE CALCULATIONX2.1Phase Net Intensity (after correction),counts s/b-TCP 23.9CaO 12.4HA 603.2Standard 989.0X2.2 The weight percentages are determined from Equa-tion 11 of Ref (6) with the RIR, Irel, and mass absorptioncoefficients from Appendix X1.Wb2TCP5S23.91DS87.2331.78DS
41、1989.0 1.146D5 0.058 5 5.8 %(X2.1)WCaO5S12.41DS87.2331.78DS1989.0 3.375D5 0.010 5 1.0 %(X2.2)WHA5S603.22.16DS87.2331.78DS1989.0 1.276D5 0.607 5 60.7 %(X2.3)REFERENCES(1) Cook, S.D., Thomas, K.A., Kay, J.F., and Jarcho, M.,“Hydroxylapatite-Coated Titanium for Orthopedic Implant Applica-tions,” Clinic
42、al Orthopaedics, Vol 232, 1988, p. 225.(2) Cook, S.D., Kay, J.F., Thomas, K.A., and Jarcho, M., “InterfaceMechanics and Histology of Titanium and Hydroxylapatite-CoatedTitanium for Dental Implant Applications,” International Journal ofOral and Maxillofacial Implants, Vol 2, 1987, p. 15.(3) Kent, J.N
43、., Block, M.S., Finger, I.M., Guerra, L.S., Larsen, H., andMisiek, D.J., “Biointegrated Hydroxylapatite-Coated Dental Implants:5-Year Clinical Observations,” Journal of the American DentalAssociation, Vol 121, 1990, p. 138.(4) DAntonio, J.A., Capello, W.N., and Jaffe, W.L., “Hydroxylapatite-Coated H
44、ip Implants: Multicenter Three-Year Clinical and Roentgeno-graphic Results,” Clinical Orthopaedics, Vol 285, 1992, p. 102.(5) Thomas, K.A., “Hydroxyapatite Coatings,” Orthopedics, Vol 17,1994, p. 267.(6) Prevey, P.S., and Rothwell, R.J., “X-ray Diffraction Characterization ofPercent Crystallinity an
45、d Contaminants in Plasma-Sprayed Hydroxy-lapatite Coatings,” Characterization and Performance of CalciumPhosphate Coatings for Implants, ASTM STP 1196, Emanuel Horowitzand Jack E. Parr, eds., American Society for Testing and Materials,Philadelphia, PA, 1994, p. 63.ASTM International takes no positio
46、n respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.
47、This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM I
48、nternational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address sho
49、wn below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE X1.3 Mass Absorption CoefficientsPhases(s) Mass Abs
