1、Designation: B 659 90 (Reapproved 2008)e1Standard Guide forMeasuring Thickness of Metallic and Inorganic Coatings1This standard is issued under the fixed designation B 659; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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.e1NOTEThe units statement in subsection 1.3 was corrected editorially in April 2008.1. Scope1.1 This guide covers the methods f
3、or measuring the thick-ness of many metallic and inorganic coatings including elec-trodeposited, mechanically deposited, vacuum deposited, an-odic oxide, and chemical conversion coatings.1.2 This guide is limited to tests considered in ASTMstandards and does not cover certain tests that are employed
4、 forspecial applications.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this s
5、tandard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B 244 Test Method for Measurement of Thickness of An-odic Coatings on Aluminum and of Other NonconductiveCoatings on Nonmag
6、netic Basis Metals with Eddy-CurrentInstrumentsB 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of CrossSectionB 499 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis MetalsB 504 Test Me
7、thod for Measurement of Thickness of Me-tallic Coatings by the Coulometric MethodB 530 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Electrodeposited NickelCoatings on Magnetic and Nonmagnetic SubstratesB 567 Test Method for Measurement of Coating Thicknessby the Beta B
8、ackscatter MethodB 568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB 588 Test Method for Measurement of Thickness of Trans-parent or Opaque Coatings by Double-Beam InterferenceMicroscope TechniqueB 681 Test Method for Measurement of Thickness of An-odic Coatings on Aluminum
9、and of Other TransparentCoatings on Opaque Surfaces Using the Light-SectionMicroscope3B 767 Guide for Determining Mass Per Unit Area of Elec-trodeposited and Related Coatings by Gravimetric andOther Chemical Analysis Procedures2.2 ISO Standards:41463 Metal and Oxide CoatingsMeasurement of Thick-ness
10、 by Microscopic Examination of Cross Sections2128 Surface Treatment of MetalsAnodization (AnodicOxidation) of Aluminum and Its AlloysMeasurement ofthe Thickness of Oxide CoatingsNondestructive Mea-surement by Light Section Microscope2176 Petroleum Products Lubricating Grease Determinationof Dropping
11、 Point2177 Metallic CoatingsMeasurement of CoatingThicknessCoulometric Method by Anodic Solution2178 Non-Magnetic Metallic and Vitreous or PorcelainEnamel Coatings on Magnetic Basis Metals, Measurementof Coating Thickness, Magnetic Method2360 Non-Conductive Coatings on Non-Magnetic BasisMetalsMeasur
12、ement of Coating ThicknessEddy Cur-rent Method2361 Electrodeposited Nickel Coatings on Magnetic andNon-Magnetic SubstratesMeasurement of CoatingThicknessMagnetic Method3497 Metallic CoatingsMeasurement of CoatingThicknessX-Ray Spectrometric Methods1This guide is under the jurisdiction of ASTM Commit
13、tee B08 on Metallic andInorganic Coatings and is the direct responsibility of Subcommittee B08.10 on TestMethods.Current edition approved April 1, 2008. Published April 2008. Originallyapproved in 1979. Last previous edition approved in 2003 as B 65990(2003).2For referenced ASTM standards, visit the
14、 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.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New
15、 York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3543 Metallic and Non-Metallic CoatingsMeasurementof ThicknessBeta Backscatter Method3. Significance and Use3.1 Most coating specifications specify t
16、he thickness of thecoating because coating thickness is often an important factorin the performance of the coating in service.3.2 The methods included in this guide are suitable foracceptance testing and are to be found in ASTM standards.3.3 Each method has its own limitations with respect to thekin
17、d of coating and its thickness.4. Reliability of Methods4.1 All methods covered by this guide are sufficientlyreliable to be used for acceptance testing of many electroplatedand other coatings. That is, each method is capable of yieldingmeasurements with an uncertainty of less than 10 % of thecoatin
18、g thickness over a significant range of coating thick-nesses when used by properly instructed personnel.5. Nondestructive Methods5.1 Magnetic MethodsThese methods employ instru-ments that measure the magnetic attraction between a magnetand the coating or the substrate or both, or that measure therel
19、uctance of a magnetic flux path passing through the coatingand the substrate. These methods, in practice, are limited tononmagnetic coatings on carbon steel (Test Method B 499 andISO 2178) and to electrodeposited nickel coatings on carbonsteel or on nonmagnetic substrates (Test Method B 530 andISO 2
20、361) and to nonmagnetic autocatalytically depositednickel-phosphorus alloys on carbon steel (Test Method B 499and ISO 2176). Coating thickness gages of this type areavailable commercially.5.2 Eddy-Current MethodThis method employs an instru-ment that generates a high-frequency current in a probe,ind
21、ucing eddy currents near the surface of the test specimen.The magnitude of the eddy currents is a function of the relativeconductivities of the coating and substrate materials and thecoating thickness. Because variation in the electroplatingprocess can change the electrical properties of the coating
22、 and,hence, instrument response for a given thickness, the use ofeddy-current instruments is usually limited to the measurementof nonconductive coatings on nonmagnetic basis metals (TestMethod B 244 and ISO 2360). These instruments are, however,also suitable for the thickness measurement of high-con
23、ductivity metal (for example, copper and silver) coatings onnonconductive substrates. Coating thickness gages of this typeare available commercially.5.3 X-Ray Fluorescence Methods:5.3.1 These methods cover the use of emission and absorp-tion X-ray spectrometry for determining the thickness ofmetalli
24、c coatings up to about 15 m. The upper limit may besignificantly above or below 15 m depending on the coatingmaterial and on the equipment used. When exposed to X rays,the intensity of the secondary radiation emitted by the coatingor by the substrate followed by attenuation by the coating ismeasured
25、. The intensity of the secondary radiation is a functionof the coating thickness.5.3.2 In multiple coatings the X-ray method is generallyapplicable to the final metal coating.5.3.3 Suitable equipment is available commercially (TestMethod B 568 and ISO 3497).5.4 Beta Backscatter Method:5.4.1 The beta
26、 backscatter method employs radioisotopesthat emit beta radiation and a detector that measures theintensity of the beta radiation backscattered by the test speci-men. Part of the beta radiation entering the material collideswith atoms of the material and is scattered back towards thesource. The inte
27、nsity of the backscattered radiation is afunction, among others, of the coating thickness. A measure-ment is possible if the atomic number of the coating material issufficiently different from that of its substrate and if the betaradiation is of suitable energy and intensity. The method can beused f
28、or measuring both thin and thick coatings, the maximumthickness being a function of the atomic number of the coating.In practice, high atomic number coatings, such as gold, can bemeasured up to 50 m, while low atomic number coatings,such as copper or nickel, can be measured up to about 200 m.5.4.2 C
29、oating thickness gages of this type are availablecommercially (Test Method B 567 and ISO 3543).6. Semidestructive Methods6.1 Coulometric Method:6.1.1 Coating thickness may be determined by measuringthe quantity of electricity consumed in dissolving the coatingfrom an accurately defined area when the
30、 article is made anodicin a suitable electrolyte under suitable conditions. The changein potential occurring when the substrate is exposed indicatesthe end point of the dissolution. The method is applicable tomany coating-substrate combinations (Test Method B 504 andISO 2177).6.1.2 Coating thickness
31、 instruments employing this methodare available commercially.6.2 Double-Beam Interference Microscope MethodA stepis formed between the coating surface and the substrate surfaceby dissolving a small area of coating. The height of this step ismeasured with a double-beam interference microscope. Themet
32、hod is applicable to thin coatings such as usually used fordecorative chromium. It can be used to measure transparentoxide coatings without the need of forming a step (Test MethodB 588).7. Destructive Methods7.1 Microscopical MethodIn the microscopical methodthe thickness is measured in a magnified
33、image of a crosssection of the coating (Test Method B 487 and ISO 1463).7.2 Gravimetric Method (Strip and Weigh):7.2.1 The coating mass is determined by weighing thesample before and after dissolving the coating without attack ofthe substrate or by weighing the coating after dissolving thesubstrate
34、without attack of the coating.7.2.2 The coating thickness is given by the equation:t 5m 3 10d 3 A(1)B 659 90 (2008)e12where:t = thickness, m,d = density of coating material, g/cm3,m = mass of coating, mg, andA = area covered by coating, cm2.7.2.3 Procedures for applying this method to many different
35、coatings are given in Guide B 767.7.2.4 A variation of this method is to weigh the item beforeand after electroplating or, if the current efficiency is 100 %, tomeasure the coulombs passed during the electroplating todetermine the coating weight.8. Other Methods8.1 Profilometry and multiple-beam int
36、erferometry offerreliable methods of measuring coating thickness provided astep can be formed by removing a portion of the coating.8.2 The light section microscope is used for measuring thethickness of non-opaque coatings on relatively smooth sub-strates (Test Method B 681 and ISO 2128).9. Summary o
37、f Applicability of Coating ThicknessMeasuring Methods9.1 The applicability and limitations of coating gages andother methods of measuring coating thickness are set forth inthe pertinent ASTM and ISO standards, publications on elec-troplating and related finishing technology, and manufacturersinstruc
38、tions for the use of coating thickness gages. The X-ray,gravimetric, microscopical, and interference microscopicalmethods are applicable to almost all combinations of substrateand coatings. Table 1 indicates the substrate and coatingcombinations to which the beta backscatter, coulometric,eddy-curren
39、t, and magnetic methods have been applied.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 t
40、he riskof infringement 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
41、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 shoul
42、dmake 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 Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtain
43、ed 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).TABLE 1 Applicability of Coating Thickness Measuring MethodsNOTEB = Beta backscatter; C = Coulometric; E = Eddy current; and M = Magnetic.C
44、oatingsSubstrates Copper NickelChro-miumAuto-catalyticNickelZincCad-miumGoldPalla-diumRhod-iumSilver Tin LeadTin-LeadAlloysNon-metalsVitreousand Por-celainEnamelsMagnetic steel (includingcorrosion-resisting steel)CM CMACM CBMACM BCM BM BM BM BCM BCM BCM BCCCMBM MNonmagnetic stainless steels CEDCMACC
45、BCBCBBBBCEDBC BC BCCCBE ECopper and alloys C only onbrass andCu-BeCMACCBBBBBBBCBCBCCCBE EZinc and alloys C MA. . .BBBBBBBBCBE .Aluminum and alloys BC BCMABC BCBEA,BBCBCBBBBCBCBCBCCCEEMagnesium and alloys B BMABB BBBBBBBBBCE .Nickel C . C . C BC BBBBCBCBCBCCCBE .Silver B BMAB B B . B . . . . BC BCBE
46、EGlass Sealing Nickel-cobalt-ironalloys UNS No. K94610MCAMCBMAMBMBMBMBMBMBMBCMBACCM BM .Nonmetals BCEDBCMABC BCBBCBCBBBBCBCBCBCCC. .Titanium B BMABCBBEA,BBBBBBBBBBCBE .AMethod is sensitive to permeability variations of the coating.BMethod is sensitive to variations in the phosphorus content of the coating.CMethod is sensitive to alloy composition.DMethod is sensitive to conductivity variations of the coating.B 659 90 (2008)e13
