1、Designation: D 4764 01 (Reapproved 2006)Standard Test Method forDetermination by X-ray Fluorescence Spectroscopy ofTitanium Dioxide Content in Paint1This standard is issued under the fixed designation D 4764; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of titaniumdioxide content in liquid
3、paint. This test method is applicableto both water-reducible and solvent-reducible paints.1.2 The values stated in SI units ae 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, assoc
4、iated 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:2D 1193
5、Specification for Reagent WaterD 1394 Test Methods for Chemical Analysis of WhiteTitanium PigmentsD 2369 Test Method for Volatile Content of CoatingsD 3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD 3980 Practice for Interlaboratory Testing of Paint andRelated Materials3E 180
6、 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3. Summary of Test Method3.1 Paint containing a known amount of titanium dioxide isused as the reference standard. A solution of tetraethylammo-nium bromide in 2-ethoxyethanol is add
7、ed 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 comparing the ratio of the intens
8、ities 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 that significantly influence th
9、e opacity, color,durability, and other properties of coatings. This test methodfor determining titanium dioxide content is quicker and easierto use than Test Methods D 1394, a wet chemical analysismethod for pigments. It is conveniently applicable to singlesamples and to large numbers of samples. On
10、ly 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 of the baseline corrected i
11、ntensity 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 manufacturer of theinstrument
12、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 theoutcome of the analysis.5.
13、2 Paint Shaker.5.3 Film Applicator, to produce a 75-m (3-mil) wet filmthickness.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint
14、Materials.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1988. Last previous edition approved in 2001 as D 4764 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStand
15、ards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Plastic Sheet,4with no interfering X-ray fluorescencepeaks and not attacked by pa
16、int solvent.5.5 Perforated Suction Plate, or other flat surface.5.6 Vials and caps,20mL.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests, unless otherwise specified. It is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents
17、 of the American Chemical Society wheresuch specifications are available.5Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated, refer
18、encesto water shall be understood to mean reagent water thatconforms to the requirements of Type II of SpecificationD 1193.6.3 2-ethoxyethanol, purified grade.6.4 Tetraethylammonium Bromide, internal standardsolutionInto a 100-mL volumetric flask weigh approxi-mately 10.80 g of tetraethylammonium br
19、omide (TEAB) to 1mg. 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 used as an internal standardfor both water-reducible and solvent-reducible paint. However,water may be substituted for 2-ethoxyeth
20、anol, 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 be danger-ous to both the operator and persons in the immediate vicinityunless safety precautions are strictly observed. Theref
21、ore, 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 passes through anymaterial. It is strongly recommended that users check thedegree of exposure by film carried on them or by the
22、 use ofdosimeters and that blood counts be made periodically. Beforeutilizing the equipment, all persons designated or authorized tooperate X-ray instrumentation or supervise its operation,should have a full understanding of its nature and should alsobecome familiar with established safe exposure fa
23、ctors by acareful study of the National Bureau of Standards Handbook“X-ray Recommendations of the International Roentgen RayCommittee on X-ray Protection,”6the manufacturers instruc-tion manual, and other standard publications on the subject.Inquiries should be made of state agencies as to existingr
24、equirements.8. Specimen Preparation8.1 Thoroughly mix and sample each paint in accordancewith Practice D 3925. Prepare duplicate specimens of thestandard paint, which contains a known concentration oftitanium dioxide, and each test paint using the followingprocedure. Into a 20-mL vial weigh approxim
25、ately 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 plate. Onthe plastic sheet make a 3.0-mil (75-m) thick drawdown of theliquid paint.Air dry the drawdown film overnight. Cut from
26、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 in accordance with Test Method D 2369 if theinformation is not already available.9. Procedure9.1 Turn on the spectrometer and al
27、low it to stabilizethoroughly before beginning collection of results. With the aidof the manufacturers literature, select spectrometer settings topermit measurement of the intensity of the Ka peaks oftitanium and bromine. For instruments equipped with an X-raytube with a tungsten or chromium target,
28、 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 toward the incidentX-rays. Before measuring the specimens, record the back-ground spectrum in the ranges of the Ka peaks of titan
29、ium 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 interference is at aminimum.9.3 At the selected angles measure the background intensi-ties and the intensities of the Ka peaks
30、of titanium and brominein counts per second (c/s). Determine the net intensity, c/s, ofeach peak by subtracting the background count from the peakcount.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., Mahw
31、ah, NJ07430 were used in this test method to get these results. Please consult theresponsible technical committee1for any other suitable sources.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notliste
32、d by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.6Available from National Institute of Standards and Technology (NIST), 1
33、00Bureau Dr., Stop 3460, Gaithersburg, MD 20899-3460.TABLE 1 Instrument ConditionsTi Ka Br KaAnalyzer crystal 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 29.00D 4764 01 (2006)210
34、. Calculation10.1 Use the values of the standard paint of known TiO2content to calculate Kt, the reference intensity ratio of titaniumrelative to bromine in the film, defined as:7,8Kt5BB 1 NTB 1 N3ItIb5BT3ItIb(1)where:B = TEAB used in making film, g,= TEAB used, g, 32mL100 mL = TEAB used, g, 3150T =
35、TiO2in film, g,= paint used, g, 3 (% TiO2in dry paint/100) 3 % non-volatile matter/100,= paint used, g, 3 %TiO2in liquid paint/100,= paint used, g, 3 weight fraction of TiO2in liquidpaint,N = nonvolatile matter (from paint) in film, g,= paint used, g, 3 % nonvolatile matter/100,= paint used, g, 3 %
36、weight fraction of nonvolatilematter,Ib= intensity of bromine peak, c/s, andIt= intensity of titanium peak, c/s.ThereforeKt5BW3150X3ItIb(2)where:W = paint used, g, andX = weight fraction of TiO2in liquid paint.Calculate the mean of the Ktvalues obtained from the twodisks coated with the standard pai
37、nt 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 Sample Calculation:10.3.1 Reference intensity ratio, Kt,Standard paint12.8 % TiO2in liquid paint,Standard solution10.347 g TEAB i
38、n 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 0.0915 (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
39、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 testmethod, one operator in each of five laboratories analyzed ontwo days two samples of latex house paint and two samples ofsol
40、vent-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-laboratory coefficient of variation was 2.39 % with 19 df andthe pooled between-laboratories coefficient of variation 4.47 %with 15
41、df, after discarding one duplicate value from onelaboratory because the range differed significantly from allother duplicate ranges for paint sample Number 2. Based onthese coefficients of variation, the following criteria should beused for judging the acceptability of results at the 95 %confidence
42、level (see practices D 3980 and E 180):11.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays should be considered suspect if they differ by more than7.08 % relative.11.1.2 ReproducibilityTwo results, each the mean of du-plicate de
43、terminations, 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 because there are noaccepted standards for titanium dioxide in paints.12. Keywords12.1 titanium dioxide content; XRF spectroscopyA
44、STM 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 rights, and the riskof infringement of such rights, are
45、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 standard
46、sand 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 Committe
47、e 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,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress o
48、r at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).7Chung, 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, R. W., “AVersatile Thin Film Method forQuantitative X-ray Emission Analysis,” X-ray Spectrometry, 3(4), 1974, p. 172.D 4764 01 (2006)3
