ASTM_D_6906_-_12a.pdf

Designation:D690612aStandard Test Method forDetermination of Titanium Treatment Weight on MetalSubstrates by Wavelength Dispersive X-Ray Fluorescence1This standard is issued under the fixed designation D6906;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 wavelength disper-sive X-ray fluorescence(WDXRF)techniques for determina-tion of the coating weight of titanium treatments on metalsubstrates.These techniques are applicable for determinationof the coating weight as titanium or total coating weight of atitanium containing treatment,or both,on a variety of metalsubstrates.1.2 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 regulatory 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 Practice3.1 ExcitationThe measurement of titanium treatmentcoating weights by WDXRF methods is based on the combinedinteraction of the titanium coating and the substrate with anintense beam of primary radiation.Since each element fluo-resces at an energy characteristic of the particular element,thisinteraction results in the generation of X-rays of definedenergy.The primary radiation may be generated by an X-raytube or derived from a radioisotope.3.2 DetectionThe secondary beam(fluorescent X-rays ofthe elements and scattered radiation)is read by a detector thatcan discriminate between the energy levels of fluorescingradiations in the secondary beam.The detection system in-cludes the radiation detector with electronics for pulse ampli-fication and pulse counting.3.3 Basic Principle:3.3.1 A relationship exists between the treatment coatingweight and secondary radiation intensity.This relationship isusually linear within the desired coating weights of thetitanium treatments on metal substrates.The measurements arebased on primary standards of known coating weights andinstrument calibration that correlates the secondary radiationintensity with the coating weight quantitatively.3.3.2 The coating weight is determined by measurement ofthe fluorescent X-rays of the coating.The detection system isset to count the number of X-rays in an energy region that ischaracteristic of X-rays from the element of interest.Theelement of interest in this practice is titanium.3.3.3 If a linear relationship exists,the coating weight andnumber of counts of X-rays of a titanium treatment on aparticular substrate can be expressed by a conversion factorthat represents the number of counts for a particular coatingweight unit/unit area.This is usually expressed in mg/ft2ormg/m2of titanium or total coating weight.3.3.4 The exact relationship between the measured numberof counts and the corresponding coating weight must beestablished for each individual combination of substrate andtitanium-containing treatment.Usually determined by the treat-ment supplier,this relationship is established by using primarystandards having known amounts of the same treatment appliedto the same substrate composition as the specimens to bemeasured.3.3.5 Some X-ray apparatuses have a data handling systemwhereby a coating weight versus X-ray counts curve may beestablished within the system for the direct readout of coatingweight.If such apparatus does not permit the entry of aconversion factor as described in 3.3.3,it is calibrated using abare,untreated specimen and a minimum of three specimenswith known coating weights of the treatment and substratecombination of interest.The coating weight to be measuredmust be within the range of these known coating weights.Morethan three known specimens must be used if the relationship ofX-ray counts to coating weight is not linear over the range to1This 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 Nov.1,2012.Published January 2013.Originallyapproved in 2003.Last previous edition approved in 2012 as D6906 12.DOI:10.1520/D6906-12A.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 States1 be measured.The treatment supplier should