ASTM D7639-2010(2018) 6875 Standard Test Method for Determination of Zirconium Treatment Weight or Thickness on Metal Substrates by X-Ray Fluorescence.pdf

《ASTM D7639-2010(2018) 6875 Standard Test Method for Determination of Zirconium Treatment Weight or Thickness on Metal Substrates by X-Ray Fluorescence.pdf》由会员分享，可在线阅读，更多相关《ASTM D7639-2010(2018) 6875 Standard Test Method for Determination of Zirconium Treatment Weight or Thickness on Metal Substrates by X-Ray Fluorescence.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: D7639 10 (Reapproved 2018)Standard Test Method forDetermination of Zirconium Treatment Weight or Thicknesson Metal Substrates by X-Ray Fluorescence1This standard is issued under the fixed designation D7639; the number immediately following the designation indicates the year oforiginal a

2、doption or, in the 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) spectromet

3、ry for the determination 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 d

4、etermination using 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

5、zirconiumcontaining 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

6、The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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-pr

7、iate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelo

8、pment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlab

9、oratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 The test specimen is placed in the 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 c

10、ounts or counts persecond) is then compared to a previously prepared calibrationcurve or equation to obtain the coating 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

11、) must be established for each individual combinationof substrate and zirconium-containing treatment. Usually de-termined 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

12、test specimens to be measured.4. Significance and Use4.1 The procedure described in this test method is designedto provide 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

13、 and the zirconium coating weight of azirconium-containing treatment.5. Apparatus5.1 X-Ray Fluorescence Spectrometer, capable of measuringthe intensity of zirconium Ka or La line, and establish the1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materia

14、ls, and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved Sept. 1, 2018. Published September 2018. Originallyapproved in 2010. Last previous edition approved in 2014 as D7639 10 (2014).DOI:10.1520/D7639-10R18.2For referenced ASTM standa

15、rds, visit the 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

16、19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Te

17、chnical Barriers to Trade (TBT) Committee.1relationship 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 measuring the zirconium La line, or above18 keV

18、 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), this can be an analyzing crystal (fo

19、r example,fixed channel, goniometer) setup to detect the zirconiumX-rays (La or Ka line). Germanium 111 has been found to beacceptable for the Zirconium La line and LiF220 or LiF200 forthe zirconium Ka line.5.1.2.2 In the case of energy dispersive X-ray fluorescence(EDXRF), it can be a proportional

20、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 when measuring the zirconiumLa line in order to minimize the attenuation

21、 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 counts curve may beestablished within the system for the direct readout of coa

22、tingweight.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 Standardsshould be specimens for whichthe coating weight has been well characterized by otheranalytical procedures such as

23、x-ray photoelectronspectroscopy, Auger emission spectroscopy, glow dischargeoptical emission spectrometry, weigh-strip-weigh method, orother depth-profiling analytical technique.6.2 Blank (bare and untreated) Specimen (optional), shouldbe of the same metal substrate on which the treatment coatingwei

24、ght 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 same metalspecimen as the test specimen using a small abrasive pad.NOTE 1The fi

25、rst abrading is made parallel with the rolling direction ofthe 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 metal. This procedure should be repeated untilconstant readings are obtained.

26、 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 Specimensshall be cutto the required size, if necessary, for measurement by theinstrument.6.4 All calibration standards and test specimens shall be flatin

27、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 handheld analyzeron the standards surface.6.5 The treatment on the substrate should be uniform in thearea of measurement. If the coating

28、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. The test specimen shall be handled only bythe edges that are outside of the

29、 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 the metal. This is not necessary for instruments operatingwith a sample spinn

30、er.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 determining theintensity of the emitted zirconium radiation from each of thecalibra

31、tion 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 Construct a calibration by using the software andalgorithms supplied by the equipmen

32、t 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 Immediately after completing the calibration, determinethe zirconium coating

33、 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 thecase, the stability of the instrument and the repeatability of thesample p

34、reparation 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 Instrument SetupBefore using any XRF spectrometer,it is essential that the inst

35、rument 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 the spectrometer for analysis or, in the case ofhandheld spectrometers, place

36、the instruments analysis headagainst the test specimen to measure. If the instrument does notoperate with a sample spinner, ensure that test specimens areD7639 10 (2018)2measured with the same rolling orientation. If coating weight iseven, measure each test specimen once to obtain the zirconiumcoati

37、ng 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 recommended to measure a quality control sampleperiodically, ty

38、pically 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 zirconium treatment coatingweight (in mg/m2or mg/ft2) or thick

39、ness (in m or nm).12. 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 using the same calibrations standards and mea-sured the same test specime

40、ns (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 “test result” reported represents an individualdetermination. Except f

41、or 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 calibration standards (that is, coating treatmentdensity or coating weight w

42、ere 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” value for that material; “r”istheinterval representing the critical dif

43、ference 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)Two test results shall bejudged not equivalent if they differ by more

44、 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.12.1.2.1 Reproducibility limits are listed in Table 1.12.1.3 The above terms

45、 (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 limited number of materials tested,the precision statistics for this

46、 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 will arise, sometimes with considerably greater orsmaller frequency than

47、 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 study, there was no acceptedreference material suitable for determining

48、 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 as:F4: ZrOx-coated cold-rolled steelF8: ZrOx-coated electro-galvanize

49、d steel13. Keywords13.1 benchtop; coating weight; EDXRF; handheld; pre-treatment; substrate; thickness; treatment; WDXRF; x-rayfluorescence; zirconium3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1151. ContactASTM CustomerService at serviceastm.org.TABLE 1 Precision Data (units: nm)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitXSXsrSRrRF4 34.26 0.95 1.79 1.95 5.01 5.46F8 91.11 5.87 5.82 8.06 16.29 22.55AAverage of lab