1、Designation: D4764 01 (Reapproved 2012)Standard Test Method forDetermination by X-ray Fluorescence Spectroscopy ofTitanium Dioxide Content in Paint1This standard is issued under the fixed designation D4764; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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 determination of titaniumdioxide content in liquid pai
3、nt. This test method is applicableto both water-reducible and solvent-reducible paints.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associa
4、ted 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. Specific hazardsstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D1193 Spe
5、cification for Reagent WaterD1394 Test Methods for Chemical Analysis of White Tita-nium PigmentsD2369 Test Method for Volatile Content of CoatingsD3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD3980 Practice for Interlaboratory Testing of Paint andRelated Materials (Withdrawn
6、 1998)3E180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals (Withdrawn 2009)33. Summary of Test Method3.1 Paint containing a known amount of titanium dioxide isused as the reference standard. A solution of tetraethylammo-nium brom
7、ide in 2-ethoxyethanol is added to the standard paintand to each paint being analyzed. Drawdown films of thestandard and test paint are made on thin plastic sheets. Theintensities of key X-ray fluorescence peaks of titanium andbromine are measured. The titanium dioxide content is deter-mined by comp
8、aring the ratio of the intensities of titanium andbromine peaks in the test paint and the standard. Differences inthe nonvolatile content of the paints are taken into account inthe calculation of results.4. Significance and Use4.1 Titanium dioxide pigments are components with highrefractive index th
9、at significantly influence the opacity, color,durability, and other properties of coatings. This test methodfor determining titanium dioxide content is quicker and easierto use than Test Methods D1394, a wet chemical analysismethod for pigments. It is conveniently applicable to singlesamples and to
10、large numbers of samples. Only a singlerelatively stable reagent used to prepare standards and paintsunder test need be stored. Drawdown specimens used asstandards, once prepared, can be stored indefinitely and usedrepeatedly.5. Apparatus5.1 X-ray Fluorescence Spectrometer, suitable for measure-ment
11、 of the baseline corrected intensity of the Ka lines oftitanium and of bromine. For spectrometers equipped with atungsten or chromium target and a lithium fluoride (200)analyzing crystal, these lines are observed at 2u angles of86.09 and 29.97, respectively.NOTE 1Follow the recommendations of the ma
12、nufacturer of theinstrument used. Use operating conditions that ensure that the count ratefor bromine and titanium are within the linear response range of thedetector. Although the base operating conditions and count rate may bedifferent for different instruments, these differences will not affect t
13、heoutcome of the analysis.5.2 Paint Shaker.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jun
14、e 1, 2012. Published July 2012. Originally approvedin 1988. Last previous edition approved in 2006 as D4764 01 (2006). DOI:10.1520/D4764-01R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vo
15、lume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Film Applicator,
16、 to produce a 75-m (3-mil) wet filmthickness.5.4 Plastic Sheet,4with no interfering X-ray fluorescencepeaks and not attacked by paint solvent.5.5 Perforated Suction Plate, or other flat surface.5.6 Vials and caps, 20 mL.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tes
17、ts, unless otherwise specified. It is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.5Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyh
18、igh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water thatconforms to the requirements of Type II of SpecificationD1193.6.3 2-ethoxyethanol, purified grade.6.4 Tetrae
19、thylammonium Bromide, internal standardsolutionInto a 100-mLvolumetric flask weigh approximately10.80 g of tetraethylammonium bromide (TEAB) to 1 mg.Dissolve the TEAB in 2-ethoxyethanol, fill the flask to themark with 2-ethoxyethanol, and mix thoroughly. (TEAB dis-solved in 2-ethoxyethanol can be us
20、ed as an internal standardfor both water-reducible and solvent-reducible paint. However,water may be substituted for 2-ethoxyethanol, if only water-reducible paint is to be analyzed.)7. Hazards7.1 As exposure to excessive quantities of x-radiation isinjurious to health, X-ray producing equipment can
21、 be danger-ous to both the operator and persons in the immediate vicinityunless safety precautions are strictly observed. Therefore, usersshould avoid exposing any parts of their bodies, not only to thedirect beam, but also to secondary or scattered radiation thatoccurs when an X-ray beam strikes or
22、 passes through anymaterial. It is strongly recommended that users check thedegree of exposure by film carried on them or by the use ofdosimeters and that blood counts be made periodically. Beforeutilizing the equipment, all persons designated or authorized tooperate X-ray instrumentation or supervi
23、se its operation,should have a full understanding of its nature and should alsobecome familiar with established safe exposure factors by acareful study of the National Bureau of Standards Handbook“X-ray Recommendations of the International Roentgen RayCommittee on X-ray Protection,”6the manufacturer
24、s instruc-tion manual, and other standard publications on the subject.Inquiries should be made of state agencies as to existingrequirements.8. Specimen Preparation8.1 Thoroughly mix and sample each paint in accordancewith Practice D3925. Prepare duplicate specimens of thestandard paint, which contai
25、ns a known concentration oftitanium dioxide, and each test paint using the followingprocedure. Into a 20-mL vial weigh approximately 7.00 g ofpaint to 1 mg. Pipet 2 mL of TEAB internal standard solution(see 6.4) into the paint and thoroughly mix.8.2 Place a plastic sheet on the perforated suction pl
26、ate. Onthe plastic sheet make a 3.0-mil (75-m) thick drawdown of theliquid paint.Air dry the drawdown film overnight. Cut from thedrawdown on the plastic sheet a disk of a size appropriate forthe specimen holder of the spectrometer.8.3 Determine the percent nonvolatile content of each paintat 110C i
27、n accordance with Test Method D2369 if theinformation is not already available.9. Procedure9.1 Turn on the spectrometer and allow it to stabilizethoroughly before beginning collection of results. With the aidof the manufacturers literature, select spectrometer settings topermit measurement of the in
28、tensity of the Ka peaks oftitanium and bromine. For instruments equipped with an X-raytube with a tungsten or chromium target, the settings pre-scribed in Table 1 may be used as guidelines (Note 1).9.2 Place the disk in the specimen holder in such a way thatthe coated side of the sheet is turned tow
29、ard the incidentX-rays. Before measuring the specimens, record the back-ground spectrum in the ranges of the Ka peaks of titanium andbromine, including at least 10 on each side. Check the spectrafor the presence of interfering peaks and select for each peak anangle for background measurement where i
30、nterference is at aminimum.4Leneta P-121-10N dull black plastic panels 165 by 432 by 0.25 mm (612 by 17in. by 10 mils) in size, available from Leneta Co., 15 Whitney Rd., Mahwah, NJ07430 were used in this test method to get these results. Please consult theresponsible technical committee1for any oth
31、er suitable sources.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Unit
32、ed States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.6Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.TABLE 1 Instrument ConditionsTi Ka Br KaAnalyzer cry
33、stal LiF LiFCounter Flow or Scintillation ScintillationCollimator Fine CoarseOrder First FirstTube KV/mA 10/5 60/24Time, s 20 20Peak, 2u, 86.09 29.97Background, 2u, 85.00 29.00D4764 01 (2012)29.3 At the selected angles measure the background intensi-ties and the intensities of the Ka peaks of titani
34、um and brominein counts per second (c/s). Determine the net intensity, c/s, ofeach peak by subtracting the background count from the peakcount.10. Calculation10.1 Use the values of the standard paint of known TiO2content to calculate Kt, the reference intensity ratio of titaniumrelative to bromine i
35、n the film, defined as:7,8Kt5BB1NTB1N3ItIb5BT3ItIb(1)where:B = TEAB used in making film, g,= TEAB used, g, 2mL100 mL = TEAB used, g, 150T =TiO2in film, g,= paint used, g, (% TiO2in dry paint/100) % nonvola-tile matter/100,= paint used, g, % TiO2in liquid paint/100,= paint used, g, weight fraction of
36、 TiO2in liquid paint,N = nonvolatile matter (from paint) in film, g,= paint used, g, % nonvolatile matter/100,= paint used, g, % weight fraction of nonvolatile matter,Ib= intensity of bromine peak, c/s, andIt= intensity of titanium peak, c/s.ThereforeKt5BW3150X3ItIb(2)where:W = paint used, g, andX =
37、 weight fraction of TiO2in liquid paint.Calculate the mean of the Ktvalues obtained from the twodisks coated with the standard paint and use in the calculationin 10.2.10.2 Calculate the percent TiO2in the test paint, P,asfollows:P 52 3 B 3 ItKt3 W 3 Ib(3)where the symbols are defined as in 10.1.10.3
38、 Sample Calculation:10.3.1 Reference intensity ratio, Kt,Standard paint12.8 % TiO2in liquid paint,Standard solution10.347 g TEAB in 100-mL solution,Film2 mL of standard solution in 7.25 g of liquidstandard paint, andX-ray intensity: Ib= 4396 c/s, It= 1804 c/s.Kt510.3477.2523150!0.128!3180443965 0.09
39、15 (4)The mean of duplicate analyses is Kt= 0.0916.10.3.2 TiO2content of test paint,Data:Film2 mL of standard solution in 7.186 g wet paint, andX-ray intensity: Ib= 4272 c/s, It= 2569 c/sP 510.3477.186320.09163256942725 18.9% (5)11. Precision and Bias11.1 PrecisionIn an interlaboratory study of this
40、 testmethod, one operator in each of five laboratories analyzed ontwo days two samples of latex house paint and two samples ofsolvent-reducible house paint. The mean weight percent tita-nium dioxide in samples Number 1 through 4 was, respec-tively, 3.64, 19.1, 7.44, and 15.8 %. The pooled within-lab
41、oratory coefficient of variation was 2.39 % with 19 df andthe pooled between-laboratories coefficient of variation 4.47 %with 15 df, after discarding one duplicate value from onelaboratory because the range differed significantly from allother duplicate ranges for paint sample Number 2. Based onthes
42、e coefficients of variation, the following criteria should beused for judging the acceptability of results at the 95 %confidence level (see practices D3980 and E180):11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays should be
43、considered suspect if they differ by more than7.08 % relative.11.1.2 ReproducibilityTwo results, each the mean of du-plicate determinations, obtained by operators in different labo-ratories should be considered suspect if they differ by morethan 13.5 % relative.11.2 BiasBias cannot be determined bec
44、ause there are noaccepted standards for titanium dioxide in paints.12. Keywords12.1 titanium dioxide content; XRF spectroscopy7Chung, F. H., “A New Approach to Quantitative Multi-element X-ray Fluores-cence Analysis,” Advances in X-ray Analysis , 19, 1976, p. 81.8Chung, F. H., Lentz,A. J., and Scott
45、, R. W., “AVersatile Thin Film Method forQuantitative X-ray Emission Analysis,” X-ray Spectrometry, 3(4), 1974, p. 172.D4764 01 (2012)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this stand
46、ard are expressly advised that determination of the validity of any such patent 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 andi
47、f 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, wh
48、ich 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 Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
49、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/).D4764 01 (2012)4
