1、BRITISH STANDARD BS EN ISO 2177:2004 Metallic coatings Measurement of coating thickness Coulometric method by anodic dissolution The European Standard EN ISO 2177:2004 has the status of a British Standard ICS 25.220.40 BS EN ISO 2177:2004 This British Standard was published under the authority of th
2、e Standards Policy and Strategy Committee on 6 July 2005 BSI 6 July 2005 ISBN 0 580 46226 9 National foreword This British Standard is the official English language version of EN ISO 2177:2004. It is identical with ISO 2177:2003. It supersedes BS EN ISO 2177:1995 which is withdrawn. The UK participa
3、tion in its preparation was entrusted to Technical Committee STi/33, Electodeposited and related coatings, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement intern
4、ational publications referred to in this document may be found in the BSI Catalogue under 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 includ
5、e all the necessary provisions of a contract. Users are responsible for its correct application. 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 enquiri
6、es on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, th
7、e ISO title page, pages ii to iv, pages 1 to 14, the Annex ZA page and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM ENISO2177 May
8、2004 ICS25.220.40 SupersedesENISO2177:1994 Englishversion MetalliccoatingsMeasurementofcoatingthickness Coulometricmethodbyanodicdissolution(ISO2177:2003) RevtementsmtalliquesMesuragedelpaisseur Mthodecoulomtriquepardissolutionanodique(ISO 2177:2003) MetallischeberzgeSchichtdickenmessung Coulometris
9、chesVerfahrendurchanodischesAblsen (ISO2177:2003) ThisEuropeanStandardwasapprovedbyCENon1April2004. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographica
10、lreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManag
11、ementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spai
12、n,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO2177:2004EEN ISO
13、2177:2004 Foreword ThetextofISO2177:2003hasbeenpreparedbyTechnicalCommitteeISO/TC107“Metallic andotherinorganiccoatings”oftheInternationalOrganizationforStandardization(ISO)andhas beentakenoverasENISO2177:2004byTechnicalCommitteeCEN/TC262“Metallicandother inorganiccoatings“,thesecretariatofwhichishe
14、ldbyBSI. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationof anidenticaltextorbyendorsement,atthelatestbyNovember2004,andconflictingnational standardsshallbewithdrawnatthelatestbyNovember2004. ThisdocumentsupersedesENISO2177:1994. AccordingtotheCEN/CENELECInternalRegul
15、ations,thenationalstandardsorganizationsof thefollowingcountriesareboundtoimplementthisEuropeanStandard:Austria,Belgium, Cyprus,CzechRepublic,Denmark,Estonia,Finland,France,Germany,Greece,Hungary, Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland, Portugal,Slovakia,Sl
16、ovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. Endorsementnotice ThetextofISO2177:2003hasbeenapprovedbyCENasENISO2177:2004withoutany modifications. NOTENormativereferencestoInternationalStandardsarelistedinAnnexZA(normative). Reference number ISO 2177:2003(E)INTERNATIONAL STANDARD ISO 2177 Third e
17、dition 2003-03-15 Metallic coatings Measurement of coating thickness Coulometric method by anodic dissolution Revtements mtalliques Mesurage de lpaisseur Mthode coulomtrique par dissolution anodique EN ISO 2177:2004 EN ISO 2177:2004 ii EN ISO 2177:2004 iiiContents Page Foreword iv 1 Scope 1 2 Normat
18、ive references . 1 3 Terms and definitions. 1 4 Principle . 2 5 Instrumentation . 2 6 Electrolyte 2 7 Factors affecting the measuring accuracy. 3 7.1 Coating thickness . 3 7.2 Current variation . 3 7.3 Area variation 3 7.4 Agitation (if required) 4 7.5 Alloy layer between coating and substrate 4 7.6
19、 Purity of coatings 4 7.7 Condition of test surface 4 7.8 Density of coating material 4 7.9 Cleanliness of the cell 4 7.10 Cleanliness of electrical connections. 4 7.11 Calibration standards (if used) 4 7.12 Non-uniform dissolution 5 8 Procedure. 5 8.1 General . 5 8.2 Preparation of test surface. 5
20、8.3 Cell application 5 8.4 Electrolysis 5 8.5 Undercoats. 5 8.6 Examination after test. 6 8.7 Coatings on cylindrical specimens. 6 9 Expression of results 6 10 Measurement uncertainty. 7 11 Test report 7 Annex A (informative) Typical electrolytes 8 Annex B (informative) Types of instrument . 13 EN I
21、SO 2177:2004 iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national 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 subje
22、ct for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC
23、) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the 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 committe
24、es are circulated to the member bodies for voting. Publication as an International Standard requires approval by 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 h
25、eld responsible for identifying any or all such patent rights. ISO 2177 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings, Subcommittee SC 2, Test methods. This third edition cancels and replaces the second edition (ISO 2177:1985), which has been technically revis
26、ed. EN ISO 2177:2004 1Metallic coatings Measurement of coating thickness Coulometric method by anodic dissolution 1 Scope This International Standard describes a coulometric method, by anodic dissolution, for measuring the thickness of metallic coatings. It is only applicable to conductive coatings.
27、 Typical combinations of coatings and substrates that can be tested by this method are given in Table 1. Other combinations may be tested with electrolytes in current use (see Annex A), or new electrolytes may be developed for them but, in both cases, it is necessary to verify the suitability of the
28、 complete system. This International Standard is also applicable to multi-layer systems, e.g Cu-Ni-Cr (see also 8.5). It may be used to measure the thickness of coatings applied by various means, if due account is taken of special features such as the presence of an alloy layer. In some cases, the p
29、resence and thickness of diffusion layers can also be measured. It can also be used to measure the thickness of coatings on cylindrical specimens and wires (see 8.7). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated reference
30、s, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2064:1996, Metallic and other inorganic coatings Definitions and conventions concerning the measurement of thickness ISO 2080, Surface treatment, metallic
31、and other inorganic coatings Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 2064 and ISO 2080 as well as the following apply. 3.1 measuring area area of the significant surface over which a single measurement is made NOTE The measuring ar
32、ea for this method is the area enclosed by the sealing ring of the cell. EN ISO 2177:2004 2 4 Principle A well-defined area of the coating is subjected to anodic dissolution using a suitable electrolyte. The virtually complete dissolution of the coating is detected by a change in cell voltage. The c
33、oating thickness is calculated from the quantity of electricity used, in coulombs, which in turn may be calculated from: a) the time interval between the start and the end of the test, if it is conducted at constant current density; b) the integrated quantity of electricity used in dissolving the co
34、atings. 5 Instrumentation 5.1 Suitable instruments can be constructed from readily available components but proprietary instruments are usually used (see Annex B). 5.2 Proprietary direct-reading instruments are available for use with electrolytes recommended by the manufacturer. Other instruments re
35、cord the quantity of electricity, in coulombs, used in dissolving the coating from the measuring area (see 3.1), usually in arbitrary units, from which the thickness is calculated using factors or tables. With direct reading instruments, the calculation of thickness from current density is made elec
36、tronically. 5.3 The performance of the instrument shall be checked using specimens of known coating thickness. If the instrument readings agree to within 5 % of the known thicknesses of the specimens, the instrument may be used without further adjustment; otherwise, the cause of the discrepancy shal
37、l be removed. However, proprietary instruments shall always be calibrated in accordance with the manufacturers instructions. Suitable specimens of known coating thickness shall consist of the same type of coating and substrate as the specimen to be measured, and they shall have an accuracy of 5 % or
38、 better. In measuring alloy coatings, the use of correct specimens is of particular importance. 6 Electrolyte The electrolyte shall have a known, adequate shelf-life and shall be such that: a) there is no reaction with the coating metal in the absence of an impressed flow of current; b) the coating
39、dissolves anodically at an efficiency as close to 100 % as possible; c) a detectable change in electrode potential occurs as the coating is penetrated and an increasing area of substrate is exposed; d) the test area exposed in the test cell is completely wetted. The electrolyte shall be chosen with
40、reference to the coating and substrate materials, the current density and electrolyte circulation within the test cell. NOTE Typical electrolytes that have been found satisfactory for use with one type of test apparatus for testing various electrodeposited coatings on specific substrates are describ
41、ed in Annex A. For proprietary instruments, the electrolytes shall normally be chosen on the recommendations of the manufacturer. EN ISO 2177:2003 3Table 1 Typical combinations of coatings and substrates that can be tested by the coulometric method Coating Substrate (underlying material) AlaCu and C
42、u alloys Ni Ni-Co-Fe alloys Ag Steel Zn Non- metals Cd Cr Cu Only on brass and copper-beryllium Au Pb Ni Ni, autocatalyticb Ag Sn Sn-Ni alloys Sn-Pb alloysc Zn aThe detection of the change in the cell voltage may be difficult with some aluminium alloys. bThe coulometric method can only be used if th
43、e phosphorus or boron contents of these coatings are within certain limits. cThe method is sensitive to alloy composition. NOTE See Clause 5 for instrumentation. 7 Factors affecting the measuring accuracy 7.1 Coating thickness Generally, the accuracy is lower than optimum for coating thicknesses gre
44、ater than 50 m and less than 0,2 m, unless special equipment is used. With coatings thicker than 50 m, there may be an appreciable amount of bevelling or undercutting as the anodic dissolution proceeds. The amount of bevelling is largely dependent on the method employed for stirring the electrolyte.
45、 Undercutting may be eliminated, or reduced, by increasing the rate of dissolution, i.e. by increasing the current density used in the test. 7.2 Current variation For instrumentation using the constant-current and time-measuring technique, current variation causes errors. For instruments using a cur
46、rent-time integrator, too large a change in current may change the anode current efficiency and interfere with the end-point thus causing an error. 7.3 Area variation The accuracy of the thickness measurement will be no better than the accuracy to which the measuring area is known. Area variations d
47、ue to gasket wear, gasket pressure, etc., may lead to measurement errors. Much greater accuracy can be obtained if the electrolytic cells are so designed that sealing rings consistently give EN ISO 2177:2004 4 well defined measuring areas. In some cases it may be advantageous to measure the area after it has been de-plated and compensate accordingly. NOTE Error due to variations of the measuring area may, in some instances, be minimized by modifying the i
