1、BRITISH STANDARDBS EN ISO 21968:2005Non-magnetic metallic coatings on metallic and non-metallic basis materials Measurement of coating thickness Phase-sensitive eddy-current methodThe European Standard EN ISO 21968:2005 has the status of a British StandardICS 25.220.40g49g50g3g38g50g51g60g44g49g42g3
2、g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 21968:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 5 Dec
3、ember 2005 BSI 5 December 2005ISBN 0 580 46403 2National forewordThis British Standard is the official English language version of EN ISO 21968:2005. It is identical with ISO 21968:2005.The UK participation in its preparation was entrusted to Technical Committee STI/33, Electrodeposited and related
4、coatings, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue und
5、er the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct appl
6、ication. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monit
7、or related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii to iv, pages 1 to 12, an inside back cover and a back cover.The
8、 BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 21968July 2005ICS 25.220.40English VersionNon-magnetic metallic coatings on metallic and non-met
9、allicbasis materials - Measurement of coating thickness - Phase-sensitive eddy-current method (ISO 21968:2005)Revtements mtalliques non magntiques sur desmatriaux de base mtalliques et non mtalliques -Mesurage de lpaisseur de revtement - Mthode parcourants de Foucault sensible aux variations de phas
10、e (ISO21968:2005)Nichtmagnetische metallische berzge auf metallischenund nichtmetallischen Grundwerkstoffen - Messung derSchichtdicke - Phasensensitives Wirbelstromverfahren(ISO 21968:2005)This European Standard was approved by CEN on 22 June 2005.CEN members are bound to comply with the CEN/CENELEC
11、 Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN me
12、mber.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members a
13、re the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kin
14、gdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 21968:2005: EEN IS
15、O 21968:2005 Foreword This document (EN ISO 21968:2005) has been prepared by Technical Committee ISO/TC 107 “Metallic and other inorganic coatings“ in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings“, the secretariat of which is held by BSI. This European Sta
16、ndard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2006, and conflicting national standards shall be withdrawn at the latest by January 2006. According to the CEN/CENELEC Internal Regulations, the national st
17、andards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
18、 Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 21968:2005 has been approved by CEN as EN ISO 21968:2005 without any modifications. Reference numberISO 21968:2005(E)INTERNATIONAL STANDARD ISO21968First edition2005-07-15Non-magnetic metallic coat
19、ings on metallic and non-metallic basis materials Measurement of coating thickness Phase-sensitive eddy-current method Revtements mtalliques non magntiques sur des matriaux de base mtalliques et non mtalliques Mesurage de lpaisseur de revtement Mthode par courants de Foucault sensible aux variations
20、 de phase EN ISO 21968:2005ii iiiContents Page Foreword iv 1 Scope . 1 2 Principle. 1 3 Equipment . 2 4 Sampling 2 5 Factors affecting measurement accuracy2 5.1 Coating thickness. 2 5.2 Electrical properties of the basis materials . 2 5.3 Electrical properties of the coating materials 2 5.4 Basis-me
21、tal thickness 2 5.5 Edge effects. 3 5.6 Surface curvature . 3 5.7 Surface roughness . 3 5.8 Lift-off effect 3 5.9 Probe pressure 4 5.10 Probe tilt 4 5.11 Temperature effects 4 5.12 Intermediate coatings. 4 6 Procedure 4 6.1 Calibration of instruments . 4 6.2 Determination 5 7 Expression of results .
22、 6 8 Measurement uncertainty 6 9 Test report . 6 Annex A (informative) Eddy-current generation in a metallic conductor. 8 Annex B (normative) Test for edge effect 10 Bibliography . 12 EN ISO 21968:2005iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of n
23、ational standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Inter
24、national organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the
25、 rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by
26、 at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21968 was prepared by Technical Committee ISO
27、/TC 107, Metallic and other inorganic coatings, Subcommittee SC 2, Test methods. EN ISO 21968:20051Non-magnetic metallic coatings on metallic and non-metallic basis materials Measurement of coating thickness Phase-sensitive eddy-current method 1 Scope This International Standard describes a method o
28、f using phase-sensitive eddy-current instruments for non-destructive measurements of the thickness of non-magnetic metallic coatings on metallic and non-metallic basis materials, such as: a) zinc, cadmium, copper, tin or chromium on steel; b) copper or silver on composite materials. The phase-sensit
29、ive method can be applied without thickness errors to smaller surface areas and to stronger surface curvatures than the amplitude-sensitive eddy-current method described in ISO 23601, and is less affected by the magnetic properties of the basis material. However, the phase-sensitive method is more a
30、ffected by the electrical properties of the coating materials. When measuring metallic coatings on metallic basis materials, the product of conductivity and permeability (, ) of one of the materials should be at least a factor of 1,5 times the product of conductivity and permeability for the other m
31、aterial. Non-ferromagnetic materials have a relative permeability of 1. 2 Principle An eddy-current probe (or integrated probe/instrument) is placed on (or near) the surface of the coating(s) to be measured, and the thickness is read from the instruments readout. For each instrument, there is a maxi
32、mum measurable thickness of the coating. Since this thickness range depends on both the applied frequency of the probe system and the electrical properties of the coating, the maximum thickness should be determined experimentally, unless otherwise specified by the manufacturer. An explanation of edd
33、y-current generation and the calculation of the maximum measurable coating thickness, dmax, is given in Annex A. However, in the absence of any other information, the maximum measurable coating thickness, dmax, can be estimated using Equation (1): max 00,8d =(1) where 0is the standard penetration de
34、pth of the coating material see Equation (A.1). EN ISO 21968:20052 3 Equipment 3.1 Probe, containing an eddy-current generator, and a detector linked to a system capable of measuring and displaying changes in amplitude and phase, normally as a direct readout of coating thickness. NOTE 1 The probe an
35、d measuring system/display may be integrated into a single instrument. NOTE 2 Factors affecting measurement accuracy are discussed in Clause 5. 4 Sampling Sampling depends on the specific application and coating to be tested; the area, location and number of test specimens shall be agreed between in
36、terested parties and shall be included in the test report (see Clause 9). 5 Factors affecting measurement accuracy 5.1 Coating thickness A measurement uncertainty is inherent in the method. For thin coatings, this measurement uncertainty (in absolute terms) is constant, independent of the coating th
37、ickness. The absolute value of the uncertainty depends on the applied frequency of the probe system, and also on the conductivity and permeability of the used sample materials. With increasing thickness within the measurement range of the probe system, this uncertainty becomes a function of the thic
38、kness and is approximately a constant fraction of that thickness. The mean of several measurements should be used as the thickness value to reduce the uncertainty, especially in the lower part of the measurement range of the used probe system. 5.2 Electrical properties of the basis materials Both co
39、nductivity and permeability have some effect on the measurement, but these effects are small when compared to those with the amplitude method described in ISO 23601. 5.3 Electrical properties of the coating materials Coating thickness measurements are affected by the electrical conductivity of the c
40、oating material, which in turn can be dependent upon composition, the coating process (additives, contaminants, etc.) and any post-coating treatments, such as heating or mechanical working. 5.4 Basis-metal thickness For each instrument, there is a critical minimum basis-metal thickness above which m
41、easurements will not be affected by an increase in thickness. This thickness depends on both the applied frequency of the probe system and the electrical and magnetic properties of the basis material. Its value should be determined experimentally, unless otherwise specified by the manufacturer. An e
42、xplanation of eddy-current generation and the calculation of the minimum basis-material thickness, dmin, is given in Annex A. However, in the absence of any other information, the required minimum thickness of basis material, dmin, can be calculated from Equation (2): min 02,5d = (2) where 0is the s
43、tandard penetration depth of the metallic basis material see Equation (A.1). EN ISO 21968:200535.5 Edge effects Eddy-current instruments can be sensitive to abrupt changes in surface contour of the test specimen. Therefore, measurements made too near to an edge or corner may not be valid, unless the
44、 instrument has been specifically calibrated for such measurements (see 6.2.4 and Annex B). NOTE The phase-sensitive eddy-current instruments can be substantially less affected by edge effects when compared with the amplitude method of ISO 2360. 5.6 Surface curvature Measurements are affected by the
45、 curvature of the test specimen. This influence of curvature varies considerably with the make and type of instrument and probe, but always becomes more pronounced as the radius of curvature decreases. Measurements made on curved test specimens may not, therefore, be valid unless the instrument is s
46、pecifically calibrated for the surface curvature in question, or a special probe, which compensates for surface influence, is used. The effect of surface curvature can be reduced by the use of so-called microprobes, in which the radial area of probe influence has been reduced. NOTE The phase-sensiti
47、ve eddy-current measurement can be substantially less affected by the surface curvature of the test specimen when compared with the amplitude-sensitive eddy-current method given in ISO 2360. 5.7 Surface roughness Measurements are influenced by the surface topography of the basis material and of the
48、coating. Rough surfaces can cause both systematic and random errors. Random errors can be reduced by making multiple measurements, with each measurement being made at a different location, and then calculating the average value of this series of measurements. If the basis material is rough, the zero
49、 of the instrument shall be checked at several locations on a typical sample of the uncoated, rough, basis material. If no typical uncoated basis material is available, the coating of the test specimen shall be stripped, at least over part of its area, with a chemical solution which does not attack the basis material. NOTE The phase-sensitive eddy-current measurement can be substantially less affected by basis-material roughness and coating roughness when compared with the amplitude-sensitive eddy-current method given in ISO 2360
