1、Designation: D6580 00 (Reapproved 2009)D6580 17Standard Test Method forThe Determination of Metallic Zinc Content in Both ZincDust Pigment and in Cured Films of Zinc-Rich Coatings1This standard is issued under the fixed designation D6580; the number immediately following the designation indicates th
2、e year 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 by diffe
3、rential scanning calorimetry of the metallic zinc content of both zinc-dustpigment, and of dried films of zinc-rich coatings. This test method is applicable to both inorganic and organic zinc-rich coatings1.2 The values stated in SI units are to be regarded as the standard. The values given in paren
4、theses are for information only.1.3 This 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 safety, health, and healthenvironmental practices and determine theapplicabi
5、lity of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World
6、 Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D521 Test Methods for Chemical Analysis of Zinc Dust (Metallic Zinc Powder)E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Summary of Test Me
7、thod3.1 Samples of either zinc-dust pigment or of cured films of zinc-rich coatings are ground in a mortar and pestle, then carefullyweighed into standard differential scanning calorimetry (DSC) sample pans. The pans are then crimped shut, and analyzed in adifferential scanning calorimeter in a sing
8、le dynamic heating step, ranging from 370 to 435C at 10C per min, under a nitrogenpurge. The percent metallic zinc in the sample is determined by measuring the energy associated with the endothermic peak near419C caused by the melting of the metallic zinc, and comparing this value to the heat of fus
9、ion of pure zinc.4. Significance and Use4.1 This test method is useful for determining the amount of metallic zinc in zinc dust pigment, and also in dried films of bothinorganic and organic zinc-rich coatings. Test Methods D521 is an appropriate method for analyzing zinc dust, but hasshortcomings wh
10、en applied to samples of cured coatings.5. Interferences5.1 An increase or decrease in heating rate from those specified may slightly alter the results. However, the variation would beexpected to be minimal, so long as the zinc reference standard and the samples are subjected to the same heating rat
11、e.5.2 Daily calibration of the calorimeter with high purity zinc foil results in improved results. Reagent grade zinc granules orzinc powder are of insufficient purity to properly calibrate the instrument. Furthermore, the high purity-zinc foil should only beused one time as a calibration standard.
12、WarningUsing the same piece of foil more than once can result in inaccurate results,due to oxidation of the zinc at the high temperatures in the calorimeter, coupled with the alloying effects of zinc with the aluminumsample pans.1 This test method is under the jurisdiction of ASTM Committee D01 on P
13、aint 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, 2009Dec. 1, 2017. Published June 2009January 2018. Originally approved in 2000. Last previous edition appr
14、oved in 20052009 asD6580 00 (2005).(2009). DOI: 10.1520/D6580-00R09.10.1520/D6580-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary p
15、age 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 may not be technically possible to adequately depict all changes accurately, ASTM recommends that
16、 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 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Important steps in a
17、chieving accurate and reproducible results are very gentle tapping of the pan in order to distribute thesample evenly over the bottom of the pan, and careful placement of the pan lid to avoid expulsion of the fine powder duringcrimping.NOTE 1Round-robin testing has shown no evidence that pyrolysis o
18、f the binder interferes with the measurement of the heat of fusion. Either pyrolysisdoes not occur, occurs during stabilization of the instrument prior to the scan, or is negligible due to the small amount of binder present in such coatings.If there is reason to suspect interference from the binder,
19、 the analyst may wish to test a blank sample of binder (with no zinc pigment) to ensure that thereis no effect on heat flow measurements.6. Apparatus6.1 Differential Scanning Calorimeter , Calorimeter, either of the heat flux or power compensation type, capable of heating ratesup to at least 10 6 1C
20、/min and of automatic recording of difference in heat input between the sample and a reference material,to the required sensitivity and precision.6.2 Sample PansAluminum or other metal pans of high thermal conductivity are appropriate. A method or instrument forcrimping the pans shut is also necessa
21、ry.6.3 Reference MaterialHigh purity-zinc foil suitable for calibration of DSC instruments can be obtained from severalinstrument manufacturers.6.4 Nitrogen, or other inert gas supply, for blanketing the sample.6.5 Microbalance, capable of measuring to at least 10 g.6.6 Mortar and PestleAn agate mor
22、tar and pestle, of diameter approximately 29 mm (112 in.) has been found satisfactory.7. Calibration7.1 The instrument should be calibrated for heat flow as described in the manufacturersmanufacturers instruction manual. Inaddition to, or as part of the manufacturersmanufacturers standard calibratio
23、n procedure, the instrument should be calibratedusing high-purity zinc-foil reference material. Approximately 32.8 to 63.0 mg of reference material shall be weighed into astandard aluminum pan using a microbalance capable of weighing to at least 10 g. The pan shall then be crimped using analuminum l
24、id, and the reference sample analyzed in a single dynamic step ranging from 370 to 435C at 10C per min, under anitrogen purge.7.2 When analyzed as just described, the reference sample of zinc foil will give rise to an endothermic peak due to the fusionof zinc near 419C. The area under the endothermi
25、c transition, in joules per gram, should be measured either electronically ormanually, and should be very close to that for within 2 J/g of pure zinc (108 J/g).8. Procedure8.1 In the case of pigment samples, after thoroughly agitating the container in which the sample is contained, weigh 32.8 to 63.
26、0mg, to at least the nearest 10 g, into a standard aluminum pan, and crimp the pan shut. In the case of dried coating films, it isrecommended that a razor blade or razor-blade type knife be used to remove the coating from an area measuring at least 12.7 mmby 12.7 mm (12 by 12 in.) in size. This coat
27、ing should then be ground briefly, and approximately 32.8 to 63.0 mg weighed intoa standard aluminum pan, which should then be crimped shut.8.2 The sample should be analyzed in a singe dynamic step ranging from 370 to 435C at 10C per min, under a nitrogen purge.The area under the endothermic transit
28、ion corresponding to the melting (fusion) of zinc, in joules per gram, should then bedetermined in the same fashion as described for the zinc foil reference standard. Triplicate analyses should be performed, and theresults should be averaged to obtain the average heat of fusion.9. Calculation9.1 Cal
29、culate the percent metallic zinc in the sample as follows:Percent zinc metal5X/108!100 (1)where:X = measured heat of fusion of sample, in joules/gram.where:X = measured heat of fusion of sample, in joules/gram.10. Report10.1 Report the following information:10.1.1 Complete identification and descrip
30、tion of the material tested, including source and manufacturers code, if known,10.1.2 Description of instrument used for the test, andD6580 17210.1.3 Description of calibration procedure.11. Precision and Bias11.1 PrecisionAn interlaboratory evaluation of this test method with three laboratories and
31、 four materials resulted in thefollowing statistics, from Practice E691, as shown in Table 1, where Sr and r are the within laboratory standard deviation andrepeatability and SR and R are the multi-laboratory standard deviation and reproducibility: Materials I and II represent twoinorganic zinc-rich
32、 coatings, while III and IV represent two organic zinc rich coatings.11.2 Based on this, the following criteria should be used for judging the acceptability of results:11.2.1 Repeatability (Single Analyst) Analyst)The standard deviation for a single determination has been estimated to be2.8 % relati
33、ve. The 95 % limit for the difference between two such runs is 7.8 % relative.11.2.2 Reproducibility (Multilaboratory) (Multilaboratory)The coefficient of variation of results (each the average of threedeterminations), obtained by analysts in different laboratories has been estimated to be 5.0 % rel
34、ative. The 95 % limit for thedifference between two such averages is 13.9 % relative.11.2.3 BiasBias cannot be determined, as there are no standard materials available.12. Keywords12.1 differential scanning calorimetry; metallic zinc; zinc dust pigment; zinc-rich primersASTM International takes no p
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36、ility.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 A
37、STM 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 Standards, at the addres
38、s 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), 61
39、0-832-9555 (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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1 Summary of Interlaboratory Precision DataMaterials Average Sr SR r RMaterials Average Sr SR r RI 84.1000 1.9156 3.9497 5.3636 11.0591II 71.8264 1.7122 4.8757 4.7943 13.6520III 82.5222 2.0552 2.6453 5.7546 7.4068IV 69.3944 2.7797 3.5989 7.7831 10.0768D6580 173
