1、Designation: B 659 90 (Reapproved 2003)Standard 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 of
2、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 guide outlines the methods for measuring thethickness of many metallic and inorganic coatings includingelectrode
3、posited, mechanically deposited, vacuum deposited,anodic 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 forspecial applications.1.3 This standard does not purport to address all of thesafety con
4、cerns, if any, associated 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.2. Referenced Documents2.1 ASTM Standards:B 244 Test Method for Measurement of Th
5、ickness of An-odic Coatings on Aluminum and of Other NonconductiveCoatings on Nonmagnetic Basis Metals with Eddy-CurrentInstruments2B 487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination of aCross Section2B 499 Test Method for Measurement of Coating Thick-
6、nesses by the Magnetic Method: Nonmagnetic Coatings onMagnetic Basis Metals2B 504 Test Method for Measurement of Thickness of Me-tallic Coatings by the Coulometric Method2B 530 Test Method for Measurement of Coating Thick-nesses by the Magnetic Method: Electrodeposited NickelCoatings on Magnetic and
7、 Nonmagnetic Substrates2B 567 Test Method for Measurement of Coating Thicknessby the Beta Backscatter Method2B 568 Test Method for Measurement of Coating Thicknessby X-Ray Spectrometry2B 588 Test Method for Measurement of Thickness of Trans-parent or Opaque Coatings by Double-Beam InterferenceMicros
8、cope Technique2B 681 Test Method for Measurement of Thickness of An-odic Coatings on Aluminum 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 Chemica
9、l Analysis Procedures22.2 ISO Standards:1463 Metal and Oxide CoatingsMeasurement of Thick-ness by Microscopic Examination of Cross Sections42128 Surface Treatment of MetalsAnodization (AnodicOxidation) of Aluminum and Its AlloysMeasurement ofthe Thickness of Oxide CoatingsNondestructive Mea-surement
10、 by Light Section Microscope42176 Petroleum Products Lubricating Grease Determinationof Dropping Point42177 Metallic CoatingsMeasurement of CoatingThicknessCoulometric Method by Anodic Solution42178 Non-Magnetic Metallic and Vitreous or PorcelainEnamel Coatings on Magnetic Basis Metals, Measuremento
11、f Coating Thickness, Magnetic Method42360 Non-Conductive Coatings on Non-Magnetic BasisMetalsMeasurement of Coating ThicknessEddy Cur-rent Method42361 Electrodeposited Nickel Coatings on Magnetic andNon-Magnetic SubstratesMeasurement of CoatingThicknessMagnetic Method43497 Metallic CoatingsMeasureme
12、nt of CoatingThicknessX-Ray Spectrometric Methods43543 Metallic and Non-Metallic CoatingsMeasurementof ThicknessBeta Backscatter Method43. Significance and Use3.1 Most coating specifications specify the thickness of thecoating because coating thickness is often an important factorin the performance
13、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 thekind of coating and its thickness.1This guide is under the jurisdiction of ASTM Committee B08 on Metall
14、ic andInorganic Coatings and is the direct responsibility of Subcommittee B08.10 on TestMethods.Current edition approved Feb. 10, 2003. Published May 2003. Originallyapproved in 1979. Last previous edition approved in 1997 as B 659 90 (1997).2Annual Book of ASTM Standards, Vol 02.05.3Discontinued. S
15、ee 2000 Annual Book of ASTM Standards, Vol 02.05.4Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Reliability of Methods4.1 All met
16、hods 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 thecoating thickness over a significant range of coating thick-nesses when u
17、sed 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 thereluctance of a magnetic flux path passing through the coatingand the
18、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 2361) and to nonmagnetic autocatalytically depositednickel-phosphoru
19、s 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,inducing eddy currents near the surface of the test specimen.The magni
20、tude 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 and,hence, instrument response for a given thickness, the use ofed
21、dy-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-conductivity metal (for example, copper and silver) coatings onnoncond
22、uctive 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 ofmetallic coatings up to about 15 m. The upper limit may besignificantly ab
23、ove 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. The intensity of the secondary radiation is a functionof the coat
24、ing 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 backscatter method employs radioisotopesthat emit beta radiation a
25、nd 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 intensity of the backscattered radiation is afunction, among others, of
26、 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 for measuring both thin and thick coatings, the maximumthickness bei
27、ng 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 Coating thickness gages of this type are availablecommercially (Test
28、 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 article is made anodicin a suitable electrolyte under suitable con
29、ditions. 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 instruments employing this methodare available commercially.6.2 Do
30、uble-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. Themethod is applicable to thin coatings such as usually used fordecorati
31、ve 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 image of a crosssection of the coating (Test Method B 487 and ISO 1
32、463).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 without attack of the coating.7.2.2 The coating thickness is given
33、by the equation:t 5m 3 10d 3 A(1)where: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 differentcoatings are given in Guide B 767.7.2.4 A variation of this method is to weigh the it
34、em beforeand after electroplating or, if the current efficiency is 100 %, tomeasure the coulombs passed during the electroplating todetermine the coating weight.B 659 90 (2003)28. Other Methods8.1 Profilometry and multiple-beam interferometry offerreliable methods of measuring coating thickness prov
35、ided 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 of Applicability of Coating ThicknessMeasuring Methods9.1 The applicab
36、ility 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 manufacturersinstructions for the use of coating thickness gages. The X-ray,gravimetric,
37、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-current, and magnetic methods have been applied.TABLE 1 Applicability of Co
38、ating Thickness Measuring MethodsNOTEB = Beta backscatter; C = Coulometric; E = Eddy current; and M = Magnetic.CoatingsSubstratesCopper NickelChro-miumAuto-catalyticNickelZincCad-miumGoldPalla-diumRhod-iumSilver Tin LeadTin-LeadAlloysNon-metalsVitreousand Por-celainEnamelsMagnetic steel (includingco
39、rrosion-resisting steel)CM CMACM CBMACM BCM BM BM BM BCM BCM BCM BCCCMBM MNonmagnetic stainless steels CEDCMACCBCBCBBBBCEDBC BC BCCCBE ECopper and alloys C only onbrass andCu-BeCMACCBBBBBBBCBCBCCCBE EZinc and alloys C MA. . .BBBBBBBBCBE .Aluminum and alloys BC BCMABC BCBEA,BBCBCBBBBCBCBCBCCCEEMagnes
40、ium and alloys B BMABB BBBBBBBBBCE .Nickel C . C . C BC BBBBCBCBCBCCCBE .Silver B BMAB B B . B . . . . BC BCBE EGlass Sealing Nickel-cobalt-ironalloys UNS No. K94610MCAMCBMAMBMBMBMBMBMBMBCMBACCM BM .Nonmetals BCEDBCMABC BCBBCBCBBBBCBCBCBCCC. .Titanium B BMABCBBEA,BBBBBBBBBBCBE .AMethod is sensitive
41、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 (2003)3ASTM International takes no position respecting the validity
42、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 entirely their own responsibility.This standard is subject t
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45、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), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B 659 90 (2003)4
