1、Designation: D 6132 08Standard Test Method forNondestructive Measurement of Dry Film Thickness ofApplied Organic Coatings Using an Ultrasonic Gage1This standard is issued under the fixed designation D 6132; 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. Scope*1.1 This test method covers the use of ultrasonic filmthickness gages to measure accu
3、rately and nondestructively thedry film thickness of organic coatings applied over a substrateof dissimilar material. Measurements may be made on fieldstructures, on commercially manufactured products, or onlaboratory test specimens. These types of gages can accuratelymeasure the dry film thickness
4、of organic coatings on concrete,wood and wallboard substrates.1.2 This test method is not applicable to coatings that willbe readily deformable under load of the measuring instrumentas the instrument probe is placed directly on the coating surfaceto take a reading.1.3 The effective range of instrume
5、nts using the principle ofultrasonics is limited by gage design. A thickness range of 0.3to 600 mils (8 m to 15 mm) has been demonstrated.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to
6、address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 823 Practices for P
7、roducing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD 1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD 4138 Practices for Measurement of Dry Film Thicknessof Protective Coating Systems by Destructive, Cross-Sectioning
8、 MeansE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 SSPCThe Society for Protective Coatings Standards:3SSPC-PA2 Measurement of Dry Coating Thickness withMagnetic GagesSSPC
9、-PA9 Measurement of Dry Organic Coating Thicknesson Cementitious Substrates Using Ultrasonic Gages3. Summary of Test Method3.1 Instruments complying with this test method measurethickness by emitting an ultrasonic pulse into the coating thatis reflected back from the substrate to the probe. The trav
10、eltime is converted into a thickness reading. The instrument mustbe placed directly on the coating surface to take a reading.3.2 After verifying accuracy on a known coated part of theobject or material of the same kind, the instrument probe iscoupled with the coated specimen, after proper cure andco
11、nditioning according to the coating manufacturers instruc-tions.3.3 It should be recognized that the accuracy of the mea-surements can be influenced when:3.3.1 The coated object to be measured is not planar withrespect to the transducer face at the point of measurement,3.3.2 The surface roughness of
12、 the coated specimen exceedsthe coating thickness, and3.3.3 Coating density is not uniform.4. Significance and Use4.1 Many coating properties are markedly affected by thefilm thickness of the dry film such as adhesion, flexibility, andhardness. To be able to compare results obtained by differentoper
13、ators, it is essential to measure film thickness carefully.4.2 Most protective and high performance coatings areapplied to meet a requirement or a specification for the dry-filmthickness of each coat, or for the complete system, or both.Coatings must be applied within certain minimum and maxi-mum th
14、ickness tolerances in order that they can fulfill their1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition appr
15、oved July 1, 2008. Published July 2008. Originally approvedin 1997. Last previously edition approved in 2004 as D 6132 04.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
16、er to the standards Document Summary page onthe ASTM website.3Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,Pittsburgh, PA 15222-4656, http:/www.sspc.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor D
17、rive, PO Box C700, West Conshohocken, PA 19428-2959, United States.intended function. In addition to potential performance defi-ciencies, it is uneconomical to apply more material thannecessary when coating large areas such as floors and walls.4.3 Surface roughness can affect the accuracy of this te
18、stmethod. A rough surface has a tendency to scatter the ultra-sonic pulse and odd readings may occur occasionally.4.4 This test method may not be applicable to measureorganic coating thickness on all substrates. The instrumentsability to detect a distinct interface between the coating and thesubstra
19、te may be impeded if the coating and the substrate areof similar composition or if the coating is non-homogeneous.Verify operation on a known thickness of the coating/substratecombination if these circumstances are thought to exist.4.5 Multilayered coatings have many interfaces and theinstrument wil
20、l measure to the interface separating the twomost acoustically different materials. Some instruments havethe ability to detect and measure the individual layer thick-nesses in a multi-layer system.4.6 The use of this test method is not necessarily limited bythe type of substrate material as nondestr
21、uctive magnetic-typeor eddy current means.5. Apparatus5.1 Ultrasonic Gagean electronic gage with a transducerusing an ultrasonic principle and numerical techniques.6. Test Specimen6.1 When this test method is used in the field, the specimenis the coated structure or article on which the dry film thi
22、cknessis to be evaluated.6.2 For laboratory use, apply the materials to be tested topanels of the same composition, structure or article on whichthe dry film thickness is to be evaluated. Cure the organiccoating in accordance with the coating manufacturers instruc-tion.NOTE 1Coatings should be appli
23、ed in accordance with PracticesD 823, or as agreed upon between the purchaser and the seller.7. Calibration, Verification and Adjustment of Apparatus7.1 Although most ultrasonic instruments are pre-calibrated,accuracy should be verified by measuring a known thickness ofthe coating (reference standar
24、d) as determined by:7.1.1 Using a cross-sectioning method, or7.1.2 Nondestructively (that is, not destroying film integ-rity) removing and measuring the coating with a micrometer inaccordance with Test Method D 1005,or7.1.3 Cutting the product and comparing it to a shim ofknown thickness.7.2 Roughne
25、ss adversely affects accuracy. Therefore thereference standard should be smooth.7.3 Best calibration adjustment results are achieved oncoatings with a thickness equal to or greater than the coatingthickness range to be measured.NOTE 2The thickness of an organic coating can be determined inaccordance
26、 with the Test Method D 4138. While this is a destructive testmethod, it will provide an alternative test method to ensure measurementsmade in accordance with this test method are in the correct range.8. Procedure8.1 Use the instrument only after calibration has beenverified in accordance with Secti
27、on 7.8.2 Ensure that the coating is cured prior to use of theinstrument.8.3 Unless the coating is soft, a couplant may be required totransmit the ultrasonic pulse from the instruments probe intothe coating. Water is ideal for smooth, thin coatings. For roughcoatings, a glycol gel is best, provided i
28、t is not a contaminantfor the coating to be measured. Other liquids such as liquidsoap may be used. For specific information regarding the use ofcouplants, refer to the gage manufacturers instructions.8.4 Place the instruments probe flat on the surface andapply constant pressure. Hold the probe stea
29、dy during themeasurement.8.5 Take a sufficient number of readings to characterize thesurface.NOTE 3SSPC-PA2 specifies the location and number of readingsneeded to characterize a coated steel surface and SSPC-PA9 specifies thelocation and number of readings needed to characterize a coated cemen-titio
30、us surface. Select the method most appropriate for the material beingtested.9. Report9.1 Record the following information at the time of themeasurements and include in the report:9.1.1 Type of substrate,9.1.2 Type of coating, coating thickness,9.1.3 Instrument used, serial number, and any special ca
31、li-bration adjustment, and9.1.4 Mean, and standard deviation of the thickness read-ings found.9.2 Depending upon the application, it may be useful torecord the individual readings as well. For rough substrates orcoatings, it is recommended to measure the coating in accor-dance with SSPC-PA2 or SSPC-
32、PA9.10. Precision and Bias410.1 PrecisionThe precision of this test method is basedon an interlaboratory study of Test Method D 6132 - 04,conducted in 2007. Each of eight laboratories tested sevendifferent coated panels using two types of instrumentation.Every “test result” represents an individual
33、determination. Alllaboratories reported two replicate test results for every panelwith each instrument. Practice E 691 was followed for thedesign and analysis of the data; the details are given inResearch Report No. D011144.10.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory
34、 shall be judged not equivalent if theydiffer by more than the “r” value for that material; “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.4Supporting dat
35、a have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D011144.D613208210.1.1.1 Repeatability limits are listed in Table 1 and Table2.10.1.2 Reproducibility Limit (R)Two test results shall bejudged not equivalent if they differ by more than the “R”
36、valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.10.1.2.1 Reproducibility limits are listed in Table 1 andTable 2.10.1.3 The above terms (r
37、epeatability limit and reproduc-ibility limit) are used as specified in Practice E 177.10.1.4 Any judgment in accordance with statements 10.1.1and 10.1.2 would have an approximate 95 % probability ofbeing correct.10.2 BiasAt the time of the study, there was no acceptedreference material suitable for
38、 determining the bias for this testmethod, therefore no statement on bias is being made.10.3 The precision statement was determined through sta-tistical examination of 224 results, from eight laboratories, onseven coated panels. These seven coated panels were describedas the following:Panel 1: UV cu
39、red coating on hickoryPanel 2: water borne acrylic primer on plywoodPanel 3: factory primer on untextured molded hardboardPanel 4: UV cured coating on unfilled maplePanel 5: a roll and curtain coated acrylic filler/base/topcoats on hardboardPanel 6: sprayed lacquer on oakPanel 7: powder coating on m
40、edium-density fiberboard10.4 Each instruments default calibration setting was used.For best accuracy, each instrument should be checked againsta known thickness of the particular coating being measured andadjusted if necessary. To judge the equivalency of two testresults, it is recommended to choose
41、 the coating/panel combi-nation closest in characteristics to the test panel and coating.11. Keywords11.1 coating thickness; dry film thickness; nondestructivethickness; paint thickness; ultrasonic thickness gageSUMMARY OF CHANGESCommittee D01 has identified the location of selected changes to this
42、standard since the last issue(D 6132 - 04) that may impact the use of this standard. (Approved July 1, 2008.)(1) Section 2 Referenced Documents was expanded toinclude a new paint application standard from SSPC entitledSSPC-PA9.(2) Section 10 A precision and bias statement based on theresults of a ro
43、und-robin study was added.ASTM 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 infrin
44、gement 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
45、 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
46、 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,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting
47、 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).TABLE 1 PosiTector 200 Coating Thickness (m)PanelAverageAxRepeatabilityStandardDeviationSrReproducibilityStandardDeviationSRRepeatabilityLimitrReproducibil
48、ityLimitR1 77.05 2.31 2.69 6.47 7.522 52.86 2.52 4.16 7.05 11.663 59.48 1.25 2.65 3.51 7.434 51.73 2.09 2.64 5.85 7.395 66.01 1.64 1.70 4.59 4.766 81.50 1.89 4.08 5.30 11.437 139.5 2.03 7.47 5.70 20.91AThe average of the laboratories calculated averages.TABLE 2 Quintsonic Coating Thickness (m)PanelA
49、verageAxRepeatabilityStandardDeviationSrReproducibilityStandardDeviationSRRepeatabilityLimitrReproducibilityLimitR1 71.92 2.54 3.21 7.11 8.982 41.55 1.81 6.93 5.08 19.413 55.63 1.94 3.90 5.44 10.924 47.53 0.89 1.35 2.50 3.795 64.73 1.00 1.80 2.80 5.046 75.20 0.87 3.21 2.44 9.007 114.9 1.50 5.44 4.19 15.24AThe average of the laboratories calculated averages.D6132083
