1、Designation: D5381 93 (Reapproved 2014)Standard Guide forX-Ray Fluorescence (XRF) Spectroscopy of Pigments andExtenders1This standard is issued under the fixed designation D5381; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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 guide covers the general considerations for properuse of X-ray fluorescence (XRF) spectroscopy. Because m
3、anydifferences exist between XRF instruments, no detailed oper-ating instructions are provided. The analyst should follow theinstructions provided by the manufacturer for his instrument.1.2 The analyst is encouraged to consult the chemicalliterature, various trade journals, pigment supplierpublicati
4、ons, etc., as well as the instrument manuals from themanufacturer.1.3 XRF is commonly employed to determine the elementspresent in inorganic pigments and extenders, often in concertwith other analysis techniques. Organic pigments cannot nor-mally be identified solely by XRF. On occasion, organicpigm
5、ents contain heavier elements that can distinguish be-tween major classes of these pigments or may serve todistinguish one of the two distinct pigments. However, theanalyst should be wary of a qualitative pigment identificationsolely by XRF technique.1.4 This standard does not purport to address all
6、 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 to use. For specific hazardinformation see Section 3 on Radiation Conce
7、rns.2. Referenced Documents2.1 ASTM Standards:2D3925 Practice for Sampling Liquid Paints and RelatedPigmented Coatings3. Radiation Concerns3.1 Modern XRF instrumentation has been designed tominimize exposure of laboratory personnel to X-ray radiationduring instrument use. However, most laboratories
8、use dosim-etry to monitor personnel who are normally present around theXRF instrument while it is in operation. Such dosimetrydevices are normally read on a monthly basis.3.2 After XRF instrument maintenance (especially wherethe X-ray tube, detector, or shielding has been moved orreplaced), an X-ray
9、 survey of all areas around the instrument(while in operation) is recommended. The results of such asurvey should be documented and stored for future reference.3.3 It is recommended that the laboratory check its compli-ance with all applicable local, state, and federal requirements.Many companies al
10、so have policies concerning use of X-rayequipment in their laboratories.3.4 It is common laboratory practice to post placards on allentrances to the laboratories containing X-ray equipment thatindicate its presence.4. Summary of the Guide4.1 A general guide for qualitative elemental analysis ofpaint
11、 and paint components is provided. Knowledge of theelements present in a sample can be used to infer the identityof pigments and extenders that may be present. The absence ofspecific pigments and extenders can be proven by the absenceof their constituent elements. The presence or absence of toxicele
12、ments can be demonstrated. Analysis consists of irradiatingthe test specimen with monochromatic X-rays and determiningthe energy or wavelength of the fluorescent X-ray emitted bythe specimen. Since different elements emit X-rays withdifferent energy and wavelength under these conditions, theelement
13、content of the specimen can be determined by exami-nation of the X-ray spectrum. The spectrum is recorded eitheron chart paper or magnetic media. Identification of the con-stituent elements is accomplished by comparing the peaks inthe spectrum with known tabulated data, using either manual orcompute
14、r-assisted procedures.5. Significance and Use5.1 The identification of pigments in a sample of liquidpaint or paint film is often important for regulatory purposes.1This guide is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct
15、responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved July 1, 2014. Published July 2014. Originally approvedin 1993. Last previous edition approved in 2009 as D5381 93 (2009). DOI:10.1520/D5381-93R014.2For referenced ASTM standards, visit th
16、e ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. U
17、nited States1Many inorganic pigments or extenders utilized in past paintformulation are now regulated by federal, state, or municipalhealth authorities. XRF is one of the more common andconvenient methods employed to characterize the pigmentcomposition of a paint formulation.5.2 XRF techniques, in g
18、eneral, do not provide the ability toidentify the chemical nature of organic pigments. There areinstances where XRF techniques, used in tandem with otheranalytical methods, such as solid state Carbon 13 NuclearMagnetic Resonance (C-13 NMR), can identify the organicpigments utilized in coatings. Howe
19、ver, XRF provides only anelemental sketch of the inorganic pigmentation. The chemicalcomposition of the pigments is inferred by the analyst from thesamples, color, elemental information, and common sense.Small impurities are often found in pigments, so the relativeXRF intensities also serve to guide
20、 the analyst in proposing theprobable pigment present.6. Apparatus6.1 XRF SpectrometerEither an energy dispersive orwavelength dispersive X-ray fluorescence spectrometer is re-quired. The instrument should be able to operate with theanalysis chamber either evacuated or purged with helium. Theinstrum
21、ent should be able to detect all elements with atomicnumber 11 (sodium) or higher. Extension of the atomic numberrange below 11 may be desirable for some users, an optionavailable at higher cost.6.2 Sample CupsSuitable sample containers are normallyspecified in the manufacturers operating manuals. S
22、amplecontainers are after polyethylene cups that are sealed withpolyester film or polypropylene sheeting.7. Samples7.1 Samples may be either a solid or liquid sample of paintor pigment.7.1.1 Liquid paint samples may be introduced directly intothe sample containers and the container sealed to prevent
23、spillage. Normally, the XRF specimen chamber is purged withhelium while running liquid samples.7.1.2 Solid samples may be in powder form, supportedtablets (briquettes), or paint chips. If paint chips contain severaldistinct paint layers, the resulting XRF spectrum will be acompilation of elements de
24、tected in all paint layers. If asupported pellet or briquette is made prior to analysis, theanalyst should know the binders elemental composition toavoid misinterpreting the resulting spectrum. Analyze loosepowder under helium purge. Firmly briquetted samples may berun under vacuum.8. Calibration8.1
25、 Set up the XRF instrument in accordance with thespecific manufacturers instructions.8.2 Perform calibration of the XRF spectrometer based onthe manufacturers recommendation. Stainless Steel #316 discsare often used to check the operation of the XRF instrument.Because of the wide variety of XRF inst
26、ruments on the market,no specific calibration instructions will be provided.9. Interpreting Results9.1 Computerbased elemental identification routines areoften employed for determining the identity of the variousX-ray fluorescence lines. Despite the sophistication of thesesoftware routines, the anal
27、yst must be wary of placing toomuch reliance on them. It is important that the analyst checkthe identification of each peak based on the samples color andthe knowledge of the common inorganic pigments used incoatings.9.2 Some paint formulations employ inorganic driers. Theelements contained in these
28、 dryers may appear in the XRFspectrum. Normally, these peaks are of lower intensity com-pared to the intensity of the inorganic pigments.9.3 The energy dispersive XRF instruments normally pro-duce a less wellresolved X-ray spectrum than wavelengthdispersion instruments. It is even of greater importa
29、nce that theoperator use caution with computer-based peak identificationroutines.10. Keywords10.1 briquette; energy dispersive XRF; extender; inorganicdrier; pigment; spectroscopy; wavelength dispersive XRF;X-ray fluorescenceASTM International takes no position respecting the validity of any patent
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32、 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 shown below.This standard is copyrighted by
33、 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 93 (2014)2
