1、Designation: D5723 95 (Reapproved 2010)Standard Practice forDetermination of Chromium Treatment Weight on MetalSubstrates by X-Ray Fluorescence1This standard is issued under the fixed designation D5723; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 practice covers the use of X-ray fluorescence(XRF) techniques for determination o
3、f the coating weight ofchromium treatments on metal substrates. These techniques areapplicable for determination of the coating weight as chro-mium or total coating weight of a chromium-containingtreatment, or both, on a variety of metal substrates.1.2 This standard does not purport to address all o
4、f 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. Summary of Practice2.1 ExcitationThe measurement of chromium tr
5、eatmentcoating weights by XRF methods is based on the combinedinteraction of the chromium coating and 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 defin
6、ed energy.The primary radiation may be generated by an X-ray tube orderive from a radioisotope.2.2 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 be
7、am. The detection system in-cludes the radiation detector with electronics for pulse ampli-fication and pulse counting.2.3 Basic Principle:2.3.1 A relationship exists between the treatment coatingweight and secondary radiation intensity. This relationship isusually linear within the desired coating
8、weights of thechromium treatments on metal substrates. The measurementsare based on primary standards of known coating weights andinstrument calibration that correlates the secondary radiationintensity with the coating weight quantitatively.2.3.2 The coating weight is determined by measurement ofthe
9、 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 chromium.2.3.3 If a linear relationship exists, the coating weight andnumber of co
10、unts of X rays of a chromium 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 chromium or total coating weight.2.3.4 The exact relationship betwee
11、n the measured numberof counts and corresponding coating weight must be estab-lished for each individual combination of substrate andchromium-containing treatment. Usually determined by thetreatment supplier, this relationship is established by usingprimary standards having known amounts of the same
12、 treat-ment applied to the same substrate composition as the speci-mens to be measured.2.3.5 Some X-ray apparatus 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 perm
13、it the entry of aconversion factor as described in 2.3.3, 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 coatin
14、g weights. Morethan three known specimens must be used if the relationship ofX-ray counts to coating weight is not linear over the range tobe measured. The treatment supplier should be consulted forrecommendations for establishing the curve in the instrumentfor the particular treatment and substrate
15、 combination ofinterest.3. Significance and Use3.1 The procedure described in this practice is designed toprovide a method by which the coating weight of chromiumtreatments on metal substrates may be determined.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatin
16、gs, Materials, and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1, 2010. Published July 2010. Originally approvedin 1995. Last previous edition approved in 2002 as D5723 - 95 (2002). DOI:10.1520/D5723-95R10.1Copyright ASTM Int
17、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 This procedure is applicable for determination of thetotal coating weight and the chromium coating weight of achromium-containing treatment.4. Apparatus and Materials4.1 Measuring Instrument,2which is
18、 capable of determiningthe coating weights of chromium-containing treatments onmetal substrates by X-ray fluorescence is required. The treat-ment supplier should be consulted for the suitability of theinstrumentation to be used.4.2 Calibration Standard,3necessary to calibrate the instru-ment. The co
19、unt value of this standard must be specified by thetreatment supplier.4.3 Treated Coupon, on which the coating weight is to bedetermined must be cut to the required size for the instrumentfrom the treated substrate.4.4 Blank (Bare and Untreated) Coupon should be asample of the same metal substrate o
20、n which the treatmentcoating weight is to be determined. It may be necessary toprepare a blank coupon from a treated sample if an untreatedcoupon is not available. To best imitate a bare, untreated blank,abrade a treated coupon that is from the same metal specimenas the test specimen with a small ab
21、rasive pad.44.4.1 The first abrading is made parallel with the rollingdirection of the metal, the second abrading is made perpen-dicular to the rolling direction of the metal, and the thirdabrading is made parallel with the rolling direction of themetal. This procedure should be repeated until const
22、ant read-ings are obtained. Always use the same side of the metalsubstrate from which the readings of the treated coupon will betaken.5. Test Specimens5.1 All test specimens must be flat in the area of measure-ment and free of burrs and distortions that would preventproper seating in the specimen ho
23、lder.5.2 The treatment on the substrate must be uniform in thearea of measurement.5.3 The area of measurement must be maintained free offoreign materials. The specimen must be handled only by theedges that are outside of the area to be measured.5.4 The coated area of the specimen must be larger than
24、 themeasuring area.6. Procedure6.1 Operate the instrument in accordance with the manufac-turers instructions.6.2 Set the instrument settings as follows:Dial and Arm Chromium PositionSeconds indicator per treatment supplierMultiplier switch per treatment supplierResponse switch per treatment supplier
25、Range per treatment supplierMilliamps adjust for calibration of output per treatment supplier6.3 All specimens must be seated firmly and securely overthe measuring opening. The distance between the measuringapparatus and specimen must be maintained the same as thatduring the calibration. The blank a
26、nd treated specimens mustbe placed in the holder so that the rolling direction of the metalis in the same orientation. Whenever a sample tray holder is apart of the apparatus, the same opening of the slide must beused for the blank and treated specimen unless the openingshave been determined to prod
27、uce equivalent results. If it isnecessary to use a backer to hold the test specimen firmlyagainst the window, make sure that the backer is of untreatedcoupons of the same metal as the specimen. The same backermust be used for each set of measurements.6.4 Insert the chromium instrument calibration st
28、andard thathas been recommended by the treatment supplier into theinstrument, and obtain a count. Adjust the current with thecontrol knob on the probe until the count value is within60.50 % of the counts provided by the treatment supplier witheach chromium calibration standard.6.5 Obtain the counts
29、of a blank.6.6 Obtain the counts of the treated specimen.6.7 Consult the instrument manufacturers instructionmanuals for calibrating and operating procedures if the X-rayapparatus has a data handling system for direct readout ofcoating weights.7. Calculation7.1 Use 7.2-7.5 for calculating the coatin
30、g weight if anautomated data handling system is not available.7.2 The average of a minimum of three readings of both theblank and treated specimen is used to calculate the coatingweight.7.3 Calculate the delta (D) counts by subtracting the countsof the blank from the counts of the treated specimen.7
31、.4 The coating weight is calculated by dividing the Dcounts by the conversion factor that is supplied by thetreatment supplier for the particular substrate and treatmentcombination under study.Coating weight weight/unit area!5D countsconversion factor(1)Other methods as recommended by the treatment
32、suppliermay be used to calculate the coating weight.7.5 The conversion factors supplied by the treatment sup-plier are valid only for the instrument calibration procedurerecommended by the treatment supplier.8. Keywords8.1 chromium; coating weight; treatment; X-rayfluorescence2A measuring instrument
33、 such as a Portaspec, a registered trademark ofCianflone Scientific Instruments Corp., or equivalent, available from CianfloneScientific, 228 RIDC Park West Drive, Pittsburgh, PA 15275, has been foundsuitable for this purpose.3The calibration standard may be a coupon of 316 stainless steel or otherc
34、hromium standard provided by the treatment supplier, Standard Reference Material1155 (AISI 316 stainless steel) from National Institute of Standards and Technology(NIST), Office Standard Reference Materials, Gaithersburg, MD 20899, or otherchromium calibration standard as agreed upon between the pur
35、chaser and the seller.4An abrasive pad such as Scotchbrite, a registered trademark of 3M company,No. 7447 General Purpose Hand Pad or No. 96 General Purpose CommercialScouring Pad, available from 3M, St. Paul, Minnesota, or equivalent, has been foundsuitable for this purpose.D5723 95 (2010)2ASTM Int
36、ernational takes no position respecting the validity of any patent rights 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 entirel
37、y their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand sh
38、ould be addressed to ASTM International Headquarters. Your comments 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 St
39、andards, at the address shown below.This standard is copyrighted by 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 ASTM website (www.astm.org/COPYRIGHT/).D5723 95 (2010)3
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