ASTM F2024-10(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2024 − 10 (Reapproved 2021)
Standard Practice for
X-ray Diffraction Determination of Phase Content of Plasma-
Sprayed Hydroxyapatite Coatings
This standard is issued under the fixed designation F2024; 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. Scope responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This practice is for the determination, by the Reference
mine the applicability of regulatory limitations prior to use.
Intensity Ratio External Standard Method, of the percent by
1.8 This international standard was developed in accor-
weight of the crystalline phases, hydroxyapatite (HA), beta-
dance with internationally recognized principles on standard-
(whitlockite) tricalcium phosphate (β-TCP), and calcium oxide
ization established in the Decision on Principles for the
(CaO)incoatingsdepositeduponmetallicsubstratesbyplasma
Development of International Standards, Guides and Recom-
spraying hydroxyapatite.
mendations issued by the World Trade Organization Technical
1.2 A major component in plasma-sprayed HA coatings
Barriers to Trade (TBT) Committee.
other than HAis expected to be amorphous calcium phosphate
(ACP). Crystalline components other than HA that may be
2. Terminology
present include alpha- and beta- (whitlockite) tricalcium
2.1 Definitions:
phosphates, tetracalcium phosphate (TTCP), calcium oxide,
2.1.1 crystalline phases:
and calcium pyrophosphates. Quantification of the minor
Chemical and Mineral Formula PDF Card No.
crystalline components has proven to be very unreliable due to
Names
extreme overlap and confounding of X-ray diffraction peaks.
whitlockite β-Ca (PO ) 9-169
Therefore, this practice addresses the quantification of only 3 4 2
beta-tricalcium phosphate
HA, β-TCP, and CaO.
calcium phosphate α-Ca (PO ) 9-348
3 4 2
1.3 This practice was developed for plasma-sprayed HA
alpha-tricalcium phosphate
coatings with HAcontents of at least 50 % of the total coating.
It is recognized that the analysis of the crystalline components lime CaO 37-1497
calcium oxide
uses diffraction from regions of the pattern that also include a
small contribution from the amorphous component. However,
hydroxyapatite Ca (PO ) OH 9-432
5 4 3
within the limits of applicability of this practice, the effect of (hydroxylapatite)
such interference is believed to be negligible.
2.2 plasma-sprayed hydroxyapatite coating—a coating,
consisting of at least 50 % hydroxyapatite by weight, prepared
1.4 The coating analyzed shall be produced and processed
by plasma spraying hydroxyapatite on a substrate.
undermanufacturingconditionsequivalenttothoseusedonthe
device of interest.
3. Significance and Use
1.5 This practice requires the use of monochromated copper
3.1 Calcium phosphate coatings have been shown in animal
Kα radiation and flat samples.
and clinical studies to be biocompatible and to enhance the
1.6 The values stated in SI units are to be regarded as
early attachment of bone to implant surfaces (see Refs. (1-5)).
standard. No other units of measurement are included in this
3.2 It is believed that the form of calcium phosphate
standard.
ceramic and its purity with respect to secondary crystalline
1.7 This standard does not purport to address all of the
phases and amorphous material have an effect on its physical,
safety concerns, if any, associated with its use. It is the
mechanical, and biological properties. However, no definitive
studiesofeffectsonbiologicalpropertieshavebeencompleted.
To achieve reproducible clinical results and to permit the
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland
Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.13 on Ceramic Materials.
Current edition approved Feb. 1, 2021. Published February 2021. Originally Joint Committee on Powder Diffraction Standards, Swarthmore, PA.
approved in 2000. Last previous edition approved in 2016 as F2024 – 10 (2016). The boldface numbers in parentheses refer to the list of references at the end of
DOI: 10.1520/F2024-10R21. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2024 − 10 (2021)
determination of the effects of properties of the coating on surface roughness of the alpha-corundum external standard
biological performance, it is essential that the properties of must be less than 5 µm.
both clinical and experimental materials be well-characterized
5.2 X-ray Equipment:
and consistent.
5.2.1 A standard Bragg-Brentano focusing diffractometer
equipped with a pyrolytic graphite monochromator is recom-
3.3 This practice provides procedures for determination of
the percentage by weight of the crystalline phases identified as mended. Because of the need to resolve closely spaced and
overlapping peaks, a diffracted beam monochromator is re-
hydroxyapatite, β-TCP, and CaO in plasma-sprayed hydroxy-
apatite coatings. quired unless a solid-state detector is used. Linearity of the
instrument and associated electronics must be verified daily
prior to utilizing this method. Use of NIST silicon powder
4. Quantitative Phase Analysis by the External Standard
standard, SRM 640, is suggested.
Technique
5.2.2 An X-ray source with a copper target is required.
4.1 The external standard technique allows the determina-
Characteristic copper radiation provides the needed X-ray
tion of weight fractions of individual phases in a mixture
diffraction peak resolution and allows for separation of peaks
containing an amorphous fraction by comparison of the inte-
from contaminant phases at a suitable range of diffraction
grated intensity of one or more peaks from the phase(s) of
angles from nominally 20 to 60° 2θ. A 1.0° incident beam
interest to the external standard under identical instrumental
divergence, a 0.2° receiving slit, and soller slits in either the
conditions (6). The sample analyzed may be a solid such as a
incident or diffracted beam, or both, are suitable.
plasma-sprayed coating or may be a powder. The mass
5.3 X-ray Method and Data Reduction Strategy:
absorption coefficients of the sample and standard must be
5.3.1 Collect a diffraction pattern from 20 to 60° 2θ at 0.02°
known.
increments for a minimum of 1s/point.
4.2 The weight fraction of the analyte phase in the mixture
5.3.2 X-ray diffraction peaks (or peak groups) from the
is given by Equation 11 of Ref (6), as follows:
crystalline phases must be separated in order to quantify the
hkl
I χ 1
HA content. The following outline provides a data reduction
i m
W 5 · · (1)
S D S D S D
i REL Pure
I χ I ·RIR
strategy in order to provide the integrated intensities necessary
i s s i
to determine the HA, β-TCP, and CaO content of mixtures of
where:
amorphous calcium phosphate, α-TCP, β-TCP, CaO,
W = weight fraction,
i
β-Ca P O , tetracalcium phosphate, and hydroxyapatite. Ac-
hkl 2 2 7
I = integratedintensityoftheanalytephase(hkl)peakor
i
complish the determination of integrated intensities using
sum of peaks,
computer techniques, with least-squares fitting of the selected
REL
I = relative intensity of the analyte phase (hkl) peak or
i
peakshapetotheexperimentaldata.Manualfittingofpeakand
sum of peaks,
background is not permitted under this standard practice.
χ = mass absorption coefficient of the mixture,
m
5.3.2.1 Obtain the β-TCP content by integration from 30.5
χ = mass absorption coefficient of the standard,
s
Pure
to 31.5° 2θ. The β-TCP peak being used for quantification is
I = integrated intensity of the mo
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