1、Designation: D 7639 10Standard Test Method forDetermination of Zirconium Treatment Weight or Thicknesson Metal Substrates by X-Ray Fluorescence1This standard is issued under the fixed designation D 7639; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, 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 test method covers the use of X-ray fluorescence(XRF) spectrometry for the deter
3、mination of the mass ofzirconium (Zr) coating weight per unit area of metal substrates.1.2 Coating treatments can also be expressed in units oflinear thickness provided that the density of the coating isknown, or provided that a calibration curve has been estab-lished for thickness determination usi
4、ng standards with treat-ment matching this of test specimens to be analyzed. Forsimplicity, the method will subsequently refer to the determi-nation expressed as coating weight.1.3 XRF is applicable for the determination of the coatingweight as zirconium or total coating weight of a zirconiumcontain
5、ing treatment, or both, on a variety of metal substrates.1.4 The maximum measurable coating weight for a givencoating is that weight beyond which the intensity of thecharacteristic X-ray radiation from the coating or the substrateis no longer sensitive to small changes in weight.1.5 The values state
6、d in SI units are regarded as thestandard.1.6 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 regulator
7、y limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 The test specimen is placed in t
8、he X-ray beam, and theresultant peak intensity of the zirconium Ka line (at 0.0786 nmor 15.747 keV) or the zirconium La line (at 0.606 nm or 2.042keV) is measured. The intensity (in counts or counts persecond) is then compared to a previously prepared calibrationcurve or equation to obtain the coati
9、ng weight of zirconiumtreatment in mg/m2or mg/ft2(or m or nm).3.2 The exact relationship between the measured number ofcounts and the corresponding coating weight (or coatingthickness) must be established for each individual combinationof substrate and zirconium-containing treatment. Usually de-term
10、ined by the treatment supplier, this relationship is estab-lished by using primary standards having known amounts ofthe same treatment applied to the same substrate compositionas the test specimens to be measured.4. Significance and Use4.1 The procedure described in this test method is designedto pr
11、ovide a method by which the coating weight of zirconiumtreatments on metal substrates may be determined.4.2 This test method is applicable for determination of thetotal coating weight and the zirconium coating weight of azirconium-containing treatment.5. Apparatus5.1 X-Ray Fluorescence Spectrometer,
12、 capable of measur-ing the intensity of zirconium Ka or La line, and establish therelationship between peak intensity and coating weight. Thespectrometers design must include, as a minimum, the follow-ing features:5.1.1 Source of X-Ray Excitation, X-ray tube with excitationabove 2.55 keV if measurin
13、g the zirconium La line, or above18 keV if measuring the zirconium Ka line.5.1.2 X-Ray Detector, with high sensitivity and capable ofdiscriminating between zirconium La or Ka radiation and otherX-rays of higher or lower energies.5.1.2.1 In the case of wavelength dispersive X-ray fluores-cence (WDXRF
14、), this can be an analyzing crystal (for example,fixed channel, goniometer) setup to detect the zirconiumX-rays (La or Ka line). Germanium 111 has been found to be1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the di
15、rect responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1, 2010. Published June 2010. DOI:10.1520/D763910.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vo
16、lume 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.acceptable for the Zirconium La line and LiF220 or LiF200 forthe zirconium Ka line.5.1.2.2 In the case
17、of energy dispersive X-ray fluorescence(EDXRF), it can be a proportional counter, or a semiconductorsuch as a PIN diode or a silicon-drift detector.5.1.3 Pulse-Height Analyzer, or other means of energydiscrimination.5.1.4 Optical Path, specified by manufacturer. A helium orvacuum path is recommended
18、 when measuring the zirconiumLa line in order to minimize the attenuation of the X-rays bythe air in the optical path. The zirconium Ka line has a higherenergy and its intensity will not be affected by air.5.1.5 Signal Conditioning and Data Handling System,whereby a coating weight versus X-ray count
19、s curve may beestablished within the system for the direct readout of coatingweight.5.1.6 Sample Spinner (optional), to reduce the effects ofcoating weight variation across the test specimen.6. Calibration Standards and Test Specimens6.1 Calibration Standards should be specimens for whichthe coating
20、 weight has been well characterized by otheranalytical procedures such as x-ray photoelectron spectros-copy, Auger emission spectroscopy, glow discharge opticalemission spectrometry, weigh-strip-weigh method, or otherdepth-profiling analytical technique.6.2 Blank (bare and untreated) Specimen (optio
21、nal), shouldbe of the same metal substrate on which the treatment coatingweight is to be determined. It may be necessary to prepare ablank specimen from a treated specimen if an untreatedspecimen is not available. To best imitate a bare, untreatedblank, abrade a treated specimen that is from the sam
22、e metalspecimen as the test specimen using a small abrasive pad.NOTE 1The first abrading is made parallel with the rolling directionof the metal, the second abrading is made perpendicular to the rollingdirection of the metal, and the third abrading is made parallel with therolling direction of the m
23、etal. This procedure should be repeated untilconstant readings are obtained. Always use the same side of the metalsubstrate from which the readings of the treated specimen will be taken.6.3 Calibration Standards and Test Specimens shall be cutto the required size, if necessary, for measurement by th
24、einstrument.6.4 All calibration standards and test specimens shall be flatin the area of measurement and free of burrs and distortionsthat would prevent proper seating in the analysis chamber orthe specimen holder, or proper seating of the handleld analyzeron the standards surface.6.5 The treatment
25、on the substrate should be uniform in thearea of measurement. If the coating weight might vary acrossthe surface, it is recommended to analyze the test specimen inthree different areas and use the average reading as the result.6.6 The area of measurement should be maintained free offoreign materials
26、. The test specimen shall be handled only bythe edges that are outside of the area to be measured.6.7 The coated area of the test specimen should be largerthan the measured area.6.8 The calibration standards and test specimens should bemeasured over the X-ray port using the same rolling directionof
27、the metal. This is not necessary for instruments operatingwith a sample spinner.7. Calibration Procedure7.1 Set up the instrument calibration and operating param-eters according to the chemical supplier and instrument manu-facturers recommendations.7.2 Establish calibration curve by carefully determ
28、ining theintensity of the emitted zirconium radiation from each of thecalibration standards (a minimum of five standards is recom-mended). Obtain three readings for each standard (measuredacross the standards surface if it is suspected that the zirco-nium coating weight might be varying).7.3 Constru
29、ct a calibration by using the software andalgorithms supplied by the equipment manufacturer, establish-ing the relationship between zirconium intensity and zirconiumtreatment coating weight.7.4 When using drift correction monitors, determine theintensity of the drift correction monitor sample(s).7.5
30、 Immediately after completing the calibration, determinethe zirconium coating weight of one or more calibration checksample. Check samples can be stable, well-characterized ma-terials. The differences between two measured values shall bewithin the repeatability of this test method. When this is not
31、thecase, the stability of the instrument and the repeatability of thesample preparation should be investigated and correctivemeasures taken. Calibration check samples should have thesame substrate and same treatment as calibration standards andsamples to be measured.8. Preparation of Apparatus8.1 In
32、strument SetupBefore using any XRF spectrometer,it is essential that the instrument is performing to the manu-facturers specifications. Consult with the manufacturer onhow to perform spectrometer quality control checks.9. Procedure9.1 Following manufacturers instructions, place the testspecimen in t
33、he spectrometer for analysis or, in the case ofhandheld spectrometers, place the instruments analysis headagainst the test specimen to measure. If the instrument does notoperate with a sample spinner, ensure that test specimens aremeasured with the same rolling orientation. If coating weight iseven,
34、 measure each test specimen once to obtain the zirconiumcoating weight in the unknown test specimen. If coating weightis not even, measure three sub-specimens (or three differentlocations on the same specimen if spectrometer allows this),once each, and obtain the average of the readings.9.2 It is re
35、commended to measure a quality control sampleperiodically, typically on a daily basis, to verify that themethod is in statistical control.10. Calculation10.1 The zirconium coating weight on the test specimen isautomatically calculated from the calibration curve.11. Report11.1 Report the results as z
36、irconium treatment coatingweight (in mg/m2or mg/ft2) or thickness (in m or nm).D763910212. Precision and Bias312.1 The precision of this test method is based on apreliminary interlaboratory study conducted in 2009, whichincluded eight laboratories. All laboratories calibrated theirspectrometers usin
37、g the same calibrations standards and mea-sured the same test specimens (sent from one laboratory toanother in order to prevent errors due to differences in coatingthickness from set to set). The laboratories reported tenreplicate test results for each of the two different materialsprovided. Every “
38、test result” reported represents an individualdetermination. Except for the use of data representing just twomaterials, Practice E691 was followed for the design andanalysis of the data; the details are given in ASTM ResearchReport No. RR:D01-1151. Only the coating thickness wasknown for the calibra
39、tion standards (that is, coating treatmentdensity or coating weight were not known), therefore thisprecision study only shows data in thickness units (nm).12.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” va
40、lue for that material; “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.12.1.1.1 Repeatability limits are listed in Table 1.12.1.2 Reproducibility Limit (R)
41、Two test results shall bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.12.1.2.
42、1 Reproducibility limits are listed in Table 1.12.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.12.1.4 While any judgment in accordance with statement12.1.1 and 12.1.2 would have an approximate 95 % probabilityof being correct, due to the
43、 limited number of materials tested,the precision statistics for this ILS must not be treated as exactmathematical quantities which are applicable to all circum-stances and uses. The scope of the results guarantees that therewill be times when differences greater than predicted by theILS results wil
44、l arise, sometimes with considerably greater orsmaller frequency than the 95 % probability limit would imply.Consider the repeatability and reproducibility limits as ageneral guide, and the associated probability of 95 % as only arough indicator of what can be expected.12.2 BiasAt the time of the st
45、udy, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.12.3 The precision statement was determined through sta-tistical examination of 160 results, from eight laboratories, ontwo different materials, described
46、as:F4: ZrOx-coated cold-rolled steelF8: ZrOx-coated electro-galvanized steel13. Keywords13.1 benchtop; coating weight; EDXRF; handheld; pre-treatment; substrate; thickness; treatment; WDXRF; x-rayfluorescence; zirconiumASTM International takes no position respecting the validity of any patent rights
47、 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.This standard is subject to revision at any ti
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