1、Designation: D4764 01 (Reapproved 2012)D4764 01 (Reapproved 2016)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
2、 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 determination of titanium di
3、oxide content in liquid paint. This test method is applicable to bothwater-reducible and solvent-reducible paints.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the sa
4、fety 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. Specific hazards statements are given in Section 7.2. Referenced Documents2
5、.1 ASTM Standards:2D1193 Specification for Reagent WaterD1394 Test Methods for Chemical Analysis of White Titanium PigmentsD2369 Test Method for Volatile Content of CoatingsD3925 Practice for Sampling Liquid Paints and Related Pigmented CoatingsD3980 Practice for Interlaboratory Testing of Paint and
6、 Related Materials (Withdrawn 1998)3E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)33. Summary of Test Method3.1 Paint containing a known amount of titanium dioxide is used as the reference standard. A solutio
7、n of tetraethylammoniumbromide in 2-ethoxyethanol is added to the standard paint and to each paint being analyzed. Drawdown films of the standard andtest paint are made on thin plastic sheets. The intensities of key X-ray fluorescence peaks of titanium and bromine are measured.The titanium dioxide c
8、ontent is determined by comparing the ratio of the intensities of titanium and bromine peaks in the test paintand the standard. Differences in the nonvolatile content of the paints are taken into account in the calculation of results.4. Significance and Use4.1 Titanium dioxide pigments are component
9、s with high refractive index that significantly influence the opacity, color,durability, and other properties of coatings. This test method for determining titanium dioxide content is quicker and easier to usethanTest Methods D1394, a wet chemical analysis method for pigments. It is conveniently app
10、licable to single samples and to largenumbers of samples. Only a single relatively stable reagent used to prepare standards and paints under test need be stored.Drawdown specimens used as standards, once prepared, can be stored indefinitely and used repeatedly.5. Apparatus5.1 X-ray Fluorescence Spec
11、trometer, suitable for measurement of the baseline corrected intensity of the K lines of titaniumand of bromine. For spectrometers equipped with a tungsten or chromium target and a lithium fluoride (200) analyzing crystal,these lines are observed at 2 angles of 86.09 and 29.97, respectively.1 This t
12、est method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1, 2012Dec. 1, 2016. Published July 2012Decemb
13、er 2016. Originally approved in 1988. Last previous edition approved in 20062012 asD4764 01 (2006).(2012). DOI: 10.1520/D4764-01R12.10.1520/D4764-01R16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Sta
14、ndardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication o
15、f what changes have been made to the previous version. Becauseit 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 considere
16、d the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1NOTE 1Follow the recommendations of the manufacturer of the instrument used. Use operating conditions that ensure that the count rate for bromineand titanium are
17、within the linear response range of the detector. Although the base operating conditions and count rate may be different for differentinstruments, these differences will not affect the outcome of the analysis.5.2 Paint Shaker.5.3 Film Applicator, to produce a 75-m (3-mil) wet film thickness.5.4 Plas
18、tic Sheet,4with no interfering X-ray fluorescence peaks 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 be used in all tests, unless otherwise specified. It is intended that
19、 allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening t
20、he accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water that conformsto the requirements of Type II of Specification D1193.6.3 2-ethoxyethanol, purified grade.6.4 Tetraethylammonium BromideBromide, , internal stand
21、ard solutionInto a 100-mL volumetric flask weigh approximately10.80 g of tetraethylammonium bromide (TEAB) to 1 mg. Dissolve the TEAB in 2-ethoxyethanol, fill the flask to the mark with2-ethoxyethanol, and mix thoroughly. (TEAB dissolved in 2-ethoxyethanol can be used as an internal standard for bot
22、hwater-reducible and solvent-reducible paint. However, water may be substituted for 2-ethoxyethanol, if only water-reducible paintis to be analyzed.)7. Hazards7.1 As exposure to excessive quantities of x-radiation is injurious to health, X-ray producing equipment can be dangerous toboth the operator
23、 and persons in the immediate vicinity unless safety precautions are strictly observed. Therefore, users shouldavoid exposing any parts of their bodies, not only to the direct beam, but also to secondary or scattered radiation that occurs whenan X-ray beam strikes or passes through any material. It
24、is strongly recommended that users check the degree of exposure by filmcarried on them or by the use of dosimeters and that blood counts be made periodically. Before utilizing the equipment, all personsdesignated or authorized to operate X-ray instrumentation or supervise its operation, should have
25、a full understanding of its natureand should also become familiar with established safe exposure factors by a careful study of the National Bureau of StandardsHandbook “X-ray Recommendations of the International Roentgen Ray Committee on X-ray Protection,”6 the manufacturersinstruction manual, and o
26、ther 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 accordance with Practice D3925. Prepare duplicate specimens of the standardpaint, which contains a known concentration o
27、f titanium dioxide, and each test paint using the following procedure. Into a 20-mLvial weigh approximately 7.00 g of paint to 1 mg. Pipet 2 mL of TEAB internal standard solution (see 6.4) into the paint andthoroughly mix.8.2 Place a plastic sheet on the perforated suction plate. On the plastic shee
28、t make a 3.0-mil (75-m) thick drawdown of theliquid paint. Air dry the drawdown film overnight. Cut from the drawdown on the plastic sheet a disk of a size appropriate for thespecimen holder of the spectrometer.8.3 Determine the percent nonvolatile content of each paint at 110C in accordance with Te
29、st Method D2369 if the informationis not already available.9. Procedure9.1 Turn on the spectrometer and allow it to stabilize thoroughly before beginning collection of results. With the aid of themanufacturers literature, select spectrometer settings to permit measurement of the intensity of the K p
30、eaks of titanium andbromine. For instruments equipped with an X-ray tube with a tungsten or chromium target, the settings prescribed in Table 1 maybe used as guidelines (Note 1).4 Leneta P-121-10N dull black plastic panels 165 by 432 by 0.25 mm (612 by 17 in. by 10 mils) in size, available from Lene
31、ta Co., 15 Whitney Rd., Mahwah, NJ 07430were used in this test method to get these results. Please consult the responsible technical committee1 for any other suitable sources.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on
32、the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.6 Available from National Institute of
33、 Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.D4764 01 (2016)29.2 Place the disk in the specimen holder in such a way that the coated side of the sheet is turned toward the incident X-rays.Before measuring the specimens, record the backg
34、round spectrum in the ranges of the K peaks of titanium and bromine, includingat least 10 on each side. Check the spectra for the presence of interfering peaks and select for each peak an angle for backgroundmeasurement where interference is at a minimum.9.3 At the selected angles measure the backgr
35、ound intensities and the intensities of the K peaks of titanium and bromine incounts per second (c/s). Determine the net intensity, c/s, of each peak by subtracting the background count from the peak count.10. Calculation10.1 Use the values of the standard paint of known TiO2 content to calculate Kt
36、, the reference intensity ratio of titanium relativeto bromine in the film, defined as:7,8Kt 5BB1NTB1N3ItIb5BT 3 ItIb(1)where:where:B = TEAB used in making film, g,= TEAB used, g, 2 mL100 mL = TEAB used, g, 150T = TiO2 in film, g,= paint used, g, (% TiO2 in dry paint/100) % nonvolatile matter/100,=
37、paint used, g, % TiO2 in liquid paint/100,= paint used, g, weight fraction of TiO2 in 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
38、of titanium peak, c/s.ThereforeKt 5 BW 3 150X 3I tIb (2)where:W = paint used, g, andX = weight fraction of TiO2 in liquid paint.where:W = paint used, g, andX = weight fraction of TiO2 in liquid paint.Calculate the mean of the Kt values obtained from the two disks coated with the standard paint and u
39、se in the calculation in 10.2.10.2 Calculate the percent TiO2 in the test paint, P, as follows:P 523B 3I tKt 3W 3I b (3)where the symbols are defined as in 10.1.7 Chung, F. H., “A New Approach to Quantitative Multi-element X-ray Fluorescence Analysis,” Advances in X-ray Analysis, 19, 1976, p. 81.8 C
40、hung, F. H., Lentz, A. J., and Scott, R. W., “A Versatile Thin Film Method for Quantitative X-ray Emission Analysis,” X-ray Spectrometry, 3(4), 1974, p. 172.TABLE 1 Instrument ConditionsTi K Br KAnalyzer crystal LiF LiFCounter Flow or Scintillation ScintillationCollimator Fine CoarseOrder First Firs
41、tTube KV/mA 10/5 60/24Time, s 20 20Peak, 2, 86.09 29.97Background, 2, 85.00 29.00D4764 01 (2016)310.3 Sample Calculation:10.3.1 Reference intensity ratio, Kt,Standard paint12.8 % TiO2 in liquid paint,Standard solution10.347 g TEAB in 100-mL solution,Film2 mL of standard solution in 7.25 g of liquid
42、standard paint, andX-ray intensity: Ib = 4396 c/s, It = 1804 c/s.Kt 510.3477.252 3 150!0.128!31804439650.0915 (4)The mean of duplicate analyses is Kt = 0.0916.10.3.2 TiO2 content 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
43、510.3477.186 3 20.0916325694272518.9% (5)11. Precision and Bias11.1 PrecisionIn an interlaboratory study of this test method, one operator in each of five laboratories analyzed on two daystwo samples of latex house paint and two samples of solvent-reducible house paint. The mean weight percent titan
44、ium dioxide insamples Number 1 through 4 was, respectively, 3.64, 19.1, 7.44, and 15.8 %. The pooled within-laboratory coefficient of variationwas 2.39 % with 19 df and the pooled between-laboratories coefficient of variation 4.47 % with 15 df, after discarding oneduplicate value from one laboratory
45、 because the range differed significantly from all other duplicate ranges for paint sampleNumber 2. Based on these coefficients of variation, the following criteria should be used for judging the acceptability of resultsat the 95 % confidence level (see practices D3980 and E180):11.1.1 Repeatability
46、Two results, each the mean of duplicate determinations, obtained by the same operator on different daysshould be considered suspect if they differ by more than 7.08 % relative.11.1.2 ReproducibilityTwo results, each the mean of duplicate determinations, obtained by operators in different laboratorie
47、sshould be considered suspect if they differ by more than 13.5 % relative.11.2 BiasBias cannot be determined because there are no accepted standards for titanium dioxide in paints.12. Keywords12.1 titanium dioxide content; XRF spectroscopyASTM International takes no position respecting the validity
48、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 entirely their own responsibility.This standard is subject t
49、o 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 have not received a fair hearing you shouldmake your views known to the ASTM
