1、Designation: D 6132 04Standard 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 (e) 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 acc
3、urately 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 instrum
5、ents 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 as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport t
6、o 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
7、 Producing 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 Test Method for Measurement of Dry Film Thick-ness of Protective Coating Systems by Destructive MeansE 691
8、Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 SSPC The Society for Protective Coatings Standard:SSPC-PA2 Measurement of Dry Coating Thickness withMagnetic Gages33. Summary of Test Method3.1 Instruments complying with this test method measurethickness
9、by emitting an ultrasonic pulse into the coating thatis reflected back from the substrate to the probe. The traveltime 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 theobjec
10、t or material of the same kind, the instrument probe iscoupled with the coated specimen, after proper cure andconditioning 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 meas
11、ured is not planar withrespect to the transducer face at the point of measurement,3.3.2 The surface roughness of 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
12、the dry film such as adhesion, flexibility, andhardness. To be able to compare results obtained by differentoperators, 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 o
13、f each coat, or for the complete system, or both.Coatings must be applied within certain minimum and maxi-mum thickness tolerances in order that they can fulfill theirintended function. In addition to potential performance defi-ciencies, it is uneconomical to apply more material thannecessary when c
14、oating large areas such as floors and walls.4.3 Surface roughness can affect the accuracy of this testmethod. A rough surface has a tendency to scatter the ultra-sonic pulse and odd readings may occur occasionally.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related
15、Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved June 1, 2004. Published June 2004. Originallyapproved in 1997. Last previously edition approved in 1997 as D 6132 97.2For referenced AST
16、M standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from SSPC: The Society for Protective Coatings, 40 24th Street, 6thFl
17、oor, Pittsburgh PA 15222-4656.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.4 This test method may not be applicable to measureorganic coating thickness on all sub
18、strates. The instrumentsability to detect a distinct interface between the coating and thesubstrate may be impeded if the coating and the substrate areof similar composition of if the coating is non-homogeneous.Verify operation on a known thickness of the coating/substratecombination if these circum
19、stances are thought to exist.4.5 Multilayered coatings have many interfaces and theinstrument will 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 Th
20、e use of this test method is not necessarily limited bythe type of substrate material as nondestructive magnetic-typeor eddy current means.5. Apparatus5.1 Ultrasonic Gage4an electronic gage with a transducerusing an ultrasonic principle and numerical techniques (seeFig. 1).6. Test Specimen6.1 When t
21、his test method is used in the field, the specimenis the coated structure or article on which the dry film thicknessis 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. Cu
22、re the organiccoating in accordance with the coating manufacturers instruc-tion.NOTE 1Coatings should be applied 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
23、are pre-calibrated,accuracy should be verified by measuring a known thickness ofthe coating (reference standard) 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 inaccordanc
24、e with Test Method D 1005, or7.1.3 Cutting the product and comparing it to a shim ofknown thickness.7.2 Roughness 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
25、 coatingthickness range to be measured.NOTE 2The thickness of an organic coating can be determined inaccordance 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 co
26、rrect range.8. Procedure8.1 Use the instrument only after calibration has beenverified in accordance with Section 7.8.2 Ensure that the coating is dry 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 i
27、ntothe coating. Water is ideal for smooth, thin coatings. For roughcoatings, a glycol gel is best, provided it 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 ins
28、tructions.8.4 Place the instruments probe flat on the surface andapply constant pressure. Hold the probe steady 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 the surface.9.
29、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 cali-bration adjustment, and9.1.4 Mean, and standard deviation of the thickness r
30、ead-ings found.4The PosiTectort 100, a patent pending apparatus from DeFelsko Corp, 802Proctor Ave., Ogdensburg, NY 13669, is available from them as well as distributors.It has been found suitable for this use in the round-robin studies. Interested partiesare invited to submit information regarding
31、the identification of acceptable alterna-tives to this patented item to the Committee on Standards, ASTM InternationalHeadquarters, 100 Barr Harbor Drive, West Conshohocken, PA 194282959. Yourcomments will receive careful consideration at a meeting of the responsibletechnical committee,1which you ma
32、y attend.FIG. 1 Ultrasonic Film Thickness GageD61320429.2 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-PA2.10. Precision and Bias10.1 PrecisionEstimates wh
33、ere concrete is the substrateare based on an interlaboratory study in which one operator ineach of five laboratories measured three different epoxy coat-ings on two different concrete panels using this test method andan ultrasonic gage. Samples represented a wide range of dryfilm thickness. The resu
34、lts are being analyzed in accordancewith Practice E 691. Preliminary repeatability standard devia-tions where wood and wallboard was the substrate have beendetermined. The standard deviation for a coating over woodand wallboard was found to be 1.45 in microns (0.057 in mils)for both these substrates
35、 in an intra-laboratory study. Completeround-robin studies will be completed on or before December31, 2005.10.2 BiasNo information can be presented on the bias ofthe procedure in Test Method D 6132 for measuring dry filmthickness of coatings ultrasonically because no material havingan accepted refer
36、ence value is available.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 standard since the last issue(D 6132 97) that may impact the use
37、of this standard.(1) Section 1 Scope was expanded to include two moresubstrates, wood and wallboard.(2) Section 10 Preliminary repeatability data was added toPrecision and Bias.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item ment
38、ionedin 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 to revision at any time by the responsible technical committee
39、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
40、 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 address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO B
41、ox 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), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6132043
