1、Designation: D6906 11aD6906 12Standard 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 ad
2、option 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 dispersive X-ray fluores
3、cence (WDXRF) techniques for determination of thecoating weight of titanium treatments on metal substrates. These techniques are applicable for determination of the coating weightas titanium or total coating weight of a titanium containing treatment, or both, on a variety of metal substrates.1.2 Thi
4、s standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2
5、.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Summary of Practice3.1 ExcitationThe measurement of titanium treatment coating weights by WDXRF methods is
6、based on the combinedinteraction of the titanium coating and the substrate with an intense beam of primary radiation. Since each element fluoresces atan energy characteristic of the particular element, this interaction results in the generation of X-rays of defined energy. The primaryradiation may b
7、e generated by an X-ray tube or derived from a radioisotope.3.2 DetectionThe secondary beam (fluorescent X-rays of the elements and scattered radiation) is read by a detector that candiscriminate between the energy levels of fluorescing radiations in the secondary beam. The detection system includes
8、 the radiationdetector with electronics for pulse amplification and pulse counting.3.3 Basic Principle:3.3.1 A relationship exists between the treatment coating weight and secondary radiation intensity. This relationship is usuallylinear within the desired coating weights of the titanium treatments
9、on metal substrates. The measurements are based on primarystandards of known coating weights and instrument calibration that correlates the secondary radiation intensity with the coatingweight quantitatively.3.3.2 The coating weight is determined by measurement of the fluorescent X-rays of the coati
10、ng. The detection system is setto count the number of X-rays in an energy region that is characteristic of X-rays from the element of interest. The element ofinterest in this practice is titanium.3.3.3 If a linear relationship exists, the coating weight and number of counts of X-rays of a titanium t
11、reatment on a particularsubstrate can be expressed by a conversion factor that represents the number of counts for a particular coating weight unit/unit area.This is usually expressed in mg/ft2 or mg/m2 of titanium or total coating weight.3.3.4 The exact relationship between the measured number of c
12、ounts and the corresponding coating weight must be establishedfor each individual combination of substrate and titanium-containing treatment. Usually determined by the treatment supplier, thisrelationship is established by using primary standards having known amounts of the same treatment applied to
13、 the same substratecomposition as the specimens to be measured.1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1, 20
14、11July 15, 2012. Published June 2011January 2013. Originally approved in 2003. Last previous edition approved in 2011 asD6906 - 11.D6906 11A. DOI: 10.1520/D6906-11A.10.1520/D6906-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.or
15、g. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit
16、may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Ha
17、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3.5 Some X-ray apparatuses have a data handling system whereby a coating weight versus X-ray counts curve may beestablished within the system for the direct readout of coating weight. If such apparatus does not permit the ent
18、ry of a conversionfactor as described in 2.3.33.3.3, it is calibrated using a bare, untreated specimen and a minimum of three specimens with knowncoating weights of the treatment and substrate combination of interest. The coating weight to be measured must be within the rangeof these known coating w
19、eights. More than three known specimens must be used if the relationship of X-ray counts to coatingweight is not linear over the range to be measured. The treatment supplier should be consulted for recommendations forestablishing the curve in the instrument for the particular treatment and substrate
20、 combination of interest.4. Significance and Use4.1 The procedure described in this test method is designed to provide a method by which the coating weight of titaniumtreatments on metal substrates may be determined.4.2 This test method is applicable for determination of the total coating weight and
21、 the titanium coating weight of atitanium-containing treatment.5. Apparatus and Materials5.1 Measuring Instrument, which is capable of determining the coating weights of titanium-containing treatments on metalsubstrates by X-ray fluorescence is required. The treatment supplier should be consulted fo
22、r the suitability of the instrumentationto be used5.2 Calibration Standard, necessary to calibrate the instrument. The count value of this standard must be specified by thetreatment supplier.5.3 Treated Coupon, on which the coating weight is to be determined must be cut to the required size for the
23、instrument fromthe treated substrate.5.4 Blank (Bare and Untreated) Coupon should be a sample of the same metal substrate on which the treatment coating weightis to be determined. It may be necessary to prepare a blank coupon from a treated sample if an untreated coupon is not available.To best imit
24、ate a bare, untreated blank, abrade a treated coupon that is from the same metal specimen as the test specimen usinga small abrasive pad.5.4.1 The first abrading is made parallel with the rolling direction of the metal, the second abrading is made perpendicular tothe rolling direction of the metal,
25、and the third abrading is made parallel with the rolling direction of the metal. This procedureshould be repeated until constant readings are obtained. Always use the same side of the metal substrate from which the readingsof the treated coupon will be taken.6. Test Specimens6.1 All test specimens m
26、ust be flat in the area of measurement and free of burrs and distortions that would prevent proper seatingin the specimen holder.6.2 The treatment on the substrate must be uniform in the area of measurement.6.3 The area of measurement must be maintained free of foreign materials. The specimen must b
27、e handled only by the edgesthat are outside of the area to be measured.6.4 The coated area of the specimen must be larger than the measuring area.7. Procedure7.1 Operate the instrument in accordance with the manufacturers instructions.7.2 Set the instrument settings as follows:Dial and arm titanium
28、positionSeconds indicator pretreatment supplierMultiplier switch pretreatment supplierResponse switch pretreatment supplierRange pretreatment supplierMilliamps adjust for calibration of outputpretreatment supplier7.3 All specimens must be seated firmly and securely over the measuring opening. The di
29、stance between the measuringapparatus and specimen must be maintained the same as that during the calibration. The blank and treated specimens must beplaced in the holder so that the rolling direction of the metal is in the same orientation. Whenever a sample tray holder is a partof the apparatus, t
30、he same opening of the slide must be used for the blank and treated specimen unless the openings have beendetermined to produce equivalent results. If it is necessary to use a backer to hold the test specimen firmly against the window,make sure that the backer is of untreated coupons of the same met
31、al as the specimen. The same backer must be used for each setof measurements.D6906 1227.4 Insert the titanium calibration standard that has been recommended by the treatment supplier into the instrument, and obtaina count. Adjust the current with the control knob on the probe until the count value i
32、s within a single significant figure roundedapproximation of 63 times the square root of the counts provided by the treatment supplier with each titanium calibration standard.7.5 Obtain the counts of a blank.7.6 Obtain the counts of the treated specimen.7.7 Consult the instrument manufacturers instr
33、uction manuals for calibrating and operating procedures if the X-ray apparatushas a data handling system for direct readout of coating weights.8. Calculation8.1 Use 7.2-8.2-7.58.5 for calculating the coating weight if an automated data handling system is not available.8.2 The average of a minimum of
34、 three readings of both the blank and treated specimen is used to calculate the coating weight.8.3 Calculate the delta () counts by subtracting the counts of the blank from the counts of the treated specimen.8.4 The coating weight is calculated by dividing the counts by the conversion factor that is
35、 supplied by the treatment supplierfor the particular substrate and treatment combination under study.Coating weight weight/unit area!5 countsconversion factor (1)Other methods as recommended by the treatment supplier may be used to calculate the coating weight.8.5 The conversion factors supplied by
36、 the treatment supplier are valid only for the instrument calibration procedurerecommended by the treatment supplier.9. Precision and Bias9.1 The precision and bias of this test method is being determined based on an interlaboratory study of D6906and will beavailable on or before June 2012., Standar
37、d Test Method for Determination of Titanium Treatment Weight on Metal Substrates byWavelength Dispersive X-Ray Fluorescence conducted in 2011. A total of eleven laboratories tested samples prepared on threedifferent representative coil industry metal substrates, each substrate having been coated wit
38、h three different target coating weights(low, intermediate, and high) of either of two different Ti-containing commercial coil dry-in-place metal pretreatments. Eachlaboratory reported test results from triplicate samples made for each substrate/pretreatment/coating weight variation in this study.Ev
39、ery test result was the average of triplicate measurements made to determine the net (Sample Blank) WDXRF integrated Tisignal intensities of a particular sample, presumed to be proportional to its respective pretreatment coating weight. Practice E691was followed for the design and analysis of the da
40、ta; the details are given in an ASTM Research Report.39.1.1 Repeatability Limit (r)Two test results obtained within one laboratory shall be judged not equivalent if they differ bymore than the “r” value for that material; “r” is the interval representing the critical difference between two test resu
41、lts for the samepretreatment/substrate combination at the same intended applied coating weight, obtained by the same operator using the sameequipment on the same day in the same laboratory.9.1.1.1 Repeatability limits are listed in Table 1.9.1.2 Reproducibility Limit (R)Two test results shall be jud
42、ged not equivalent if they differ by more than the “R” value forthat material; “R” is the interval representing the critical difference between two test results for the same pretreatment/substratecombination at the same intended applied coating weight, obtained by different operators using different
43、 equipment in differentlaboratories.3 Research report pending.TABLE 1 Net Integrated Ti Signal Intensity (Counts)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitX sr sR r R3105 Al A 397.9 95.5 175.1 267.5 490.43105 Al B 613.6 80.9
44、183.5 226.4 513.83105 Al C 786.0 44.6 204.0 124.9 571.1NCT AZ50 A 391.7 103.0 191.0 288.4 534.8NCT AZ50 B 600.7 116.3 208.5 325.8 583.9NCT AZ50 C 720.5 207.5 347.6 581.0 973.2G70 HDG A 166.1 92.0 138.7 257.7 388.4G70 HDG B 350.2 122.7 165.8 343.6 464.2G70 HDG C 265.2 111.7 184.3 312.9 516.1A The ave
45、rage of the laboratories calculated averages.D6906 1239.1.2.1 Reproducibility limits are listed in Table 1.9.1.3 The above terms (repeatability limit and reproducibility limit) are used as specified in Practice E177.9.1.4 Any judgment in accordance with statements 9.1.1 and 9.1.2 would have an appro
46、ximate 95 % probability of beingcorrect.9.2 BiasAt the time of the study, there was no accepted reference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.9.3 The precision statement was determined through statistical examination of 293 res
47、ults, from a total of eleven laboratories,on three substrates, with three applied pretreatment target coating weights. The coating weight targets were designated in the studyas:A: Low target coating weightB: Intermediate target coating weightC: High target coating weight10. Keywords10.1 coating weig
48、ht; non-chrome; titanium; treatment; X-ray fluorescenceASTM International 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
49、rights, and the riskof infringement of such rights, are entirely 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 should 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
