ASTM_D_7639_-_10_2018.pdf

Designation:D763910(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 adoption 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)spectrometry 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 determination 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 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 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-priate 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 theDevelopment 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 Interlaboratory 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 counts 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)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 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 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,Materials,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 standards,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 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 Technical Barriers to Trade(TBT)Committee.1 relationship 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 zir