1、BSI Standards PublicationBS EN ISO 17081:2014Method of measurement of hydrogen permeation and determination of hydrogen uptake and transport in metals by an electrochemical techniqueBS EN ISO 17081:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO 17081:2
2、014. It supersedes BS EN ISO 17081:2008 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/NFE/8, Corrosion of metals and alloys.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does no
3、t purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 83840 8ICS 77.060Compliance with a British Standard cannot confer immunity from legal oblig
4、ations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2014.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 17081 June 2014 ICS 77.060 Supersedes EN IS
5、O 17081:2008English Version Method of measurement of hydrogen permeation and determination of hydrogen uptake and transport in metals by an electrochemical technique (ISO 17081:2014) Mthode de mesure de la permation de lhydrogne et dtermination de labsorption dhydrogne et de son transport dans les m
6、taux laide dune technique lectrochimique (ISO 17081:2014) Elektrochemisches Verfahren zur Messung der Wasserstoffpermeation und zur Bestimmung von Wasserstoffaufnahme und -transport in Metallen (ISO 17081:2014) This European Standard was approved by CEN on 13 April 2014. CEN members are bound to com
7、ply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELE
8、C Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the s
9、ame status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembour
10、g, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2
11、014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 17081:2014 EBS EN ISO 17081:2014EN ISO 17081:2014 (E) 3 Foreword This document (EN ISO 17081:2014) has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and
12、 alloys” in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by Decem
13、ber 2014, and conflicting national standards shall be withdrawn at the latest by December 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such paten
14、t rights. This document supersedes EN ISO 17081:2008. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finla
15、nd, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of IS
16、O 17081:2014 has been approved by CEN as EN ISO 17081:2014 without any modification. BS EN ISO 17081:2014ISO 17081:2014(E) ISO 2014 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols 25 Principle 36 Samples 46.1 Dimensions . 46.2 Pr
17、eparation 57 Apparatus . 68 Test environment considerations . 89 Test procedure 910 Control and monitoring of test environment .1111 Analysis of results.1111.1 General 1111.2 Analysis of steady-state current 1111.3 Analysis of permeation transient . 1212 Test report 14Annex A (informative) Recommend
18、ed test environments for specific alloys .16Bibliography .19BS EN ISO 17081:2014ISO 17081:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carr
19、ied 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. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
20、ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the differen
21、t approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may b
22、e the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents)
23、. Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles
24、in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 156, Corrosion of metals and alloys.This second edition cancels and replaces the first edition (ISO 17081:2004), of which it constitutes a minor r
25、evision. Figure 1 has been corrected and Figure 2 made language independent.iv ISO 2014 All rights reservedBS EN ISO 17081:2014INTERNATIONAL STANDARD ISO 17081:2014(E)Method of measurement of hydrogen permeation and determination of hydrogen uptake and transport in metals by an electrochemical techn
26、ique1 Scope1.1 This International Standard specifies a laboratory method for the measurement of hydrogen permeation and for the determination of hydrogen atom uptake and transport in metals, using an electrochemical technique. The term “metal” as used in this International Standard includes alloys.1
27、.2 This International Standard describes a method for evaluating hydrogen uptake in metals, based on measurement of steady-state hydrogen flux. It also describes a method for determining effective diffusivity of hydrogen atoms in a metal and for distinguishing reversible and irreversible trapping.1.
28、3 This International Standard gives requirements for the preparation of specimens, control and monitoring of the environmental variables, test procedures and analysis of results.1.4 This International Standard may be applied, in principle, to all metals for which hydrogen permeation is measurable an
29、d the method can be used to rank the relative aggressivity of different environments in terms of the hydrogen uptake of the exposed metal.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dat
30、ed references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 17475, Corrosion of metals and alloys Electrochemical test methods Guidelines for conducting potentiostatic and potentiodynamic polarization mea
31、surements3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1chargingmethod of introducing atomic hydrogen into the metal by exposure to an aqueous environment under galvanostatic control (constant charging current), potentiostatic control (constant
32、 electrode potential), free corrosion or by gaseous exposure3.2charging cellcompartment in which hydrogen atoms are generated on the sample surface, including both aqueous and gaseous charging3.3decay currentdecay of the hydrogen atom oxidation current, after attainment of steady state, following a
33、decrease in charging current ISO 2014 All rights reserved 1BS EN ISO 17081:2014ISO 17081:2014(E)3.4Ficks second lawsecond-order differential equation describing, in this case, the concentration of atomic hydrogen in the sample as a function of position and timeNote 1 to entry: The equation is of the
34、 form C (x, t)/t = D2C(x, t)/x2for lattice diffusion in one dimension where diffusivity is independent of concentration. See Table 1 for an explanation of the symbols.3.5hydrogen fluxamount of hydrogen passing through the metal sample per unit area per unit time3.6hydrogen uptakeatomic hydrogen abso
35、rbed into the metal as a result of charging3.7irreversible trapmicrostructural site at which the residence time for a hydrogen atom is infinite or extremely long compared to the time-scale for permeation testing at the relevant temperature3.8mobile hydrogen atomshydrogen atoms in interstitial sites
36、in the lattice (lattice sites) and reversible trap sites3.9oxidation cellcompartment in which hydrogen atoms exiting from the metal sample are oxidized3.10permeation currentcurrent measured in oxidation cell associated with oxidation of hydrogen atoms3.11permeation fluxhydrogen flux exiting the test
37、 sample in the oxidation cell3.12permeation transientvariation of the permeation current with time, from commencement of charging to the attainment of steady state, or modification of charging conditions3.13recombination poisonchemical within the test environment in the charging cell which enhances
38、hydrogen absorption by retarding the recombination of hydrogen atoms on the metal surface3.14reversible trapmicrostructural site at which the residence time for a hydrogen atom is greater than that for the lattice site but is small in relation to the time to attain steady-state permeation4 SymbolsTa
39、ble 1 gives a list of symbols and their designations.2 ISO 2014 All rights reservedBS EN ISO 17081:2014ISO 17081:2014(E)Table 1 Symbols and their designations and unitsSymbol Designation UnitA Exposed area of sample in the oxidation cell m2C(x, t) Lattice concentration of hydrogen as a function of p
40、osition and time molm3C0Sub-surface concentration of atomic hydrogen in interstitial lattice sites on the charging side of the samplemolm3C0RSummation of the sub-surface concentration of hydrogen in interstitial lattice sites and reversible trap sites on the charging side of the samplemolm3DlLattice
41、 diffusion coefficient of atomic hydrogen m2s1DeffEffective diffusion coefficient of atomic hydrogen based on elapsed time correspond-ing to J (t)/Jss= 0,63m2s1F Faradays constant (F = 96 485 Cmol1) Cmol1J (t) Time-dependent atomic hydrogen permeation flux as measured on the oxidation side of the sa
42、mplemolm2s1JssAtomic hydrogen permeation flux at steady-state as measured on the oxidation side of the samplemolm2s1J (t)/JssNormalized flux of atomic hydrogen 1I (t) Time-dependent atomic hydrogen permeation current Am2IssSteady-state atomic hydrogen permeation current Am2L Sample thickness mt Time
43、 elapsed from commencement of hydrogen charging stbElapsed time measured by extrapolating the linear portion of the rising permeation current transientstlagTime to achieve a value of J (t)/Jss= 0,63 sx Distance in sample measured in the thickness direction m Normalized time (Dlt/L2) 1lagNormalized t
44、ime to achieve a value of J (t)/Jss= 0,63 15 Principle5.1 The technique involves locating the metal sample of interest between the charging and oxidation cells, where the charging cell contains the environment of interest. Hydrogen atoms are generated on the sample surface exposed to this environmen
45、t.5.2 In gaseous environments, the hydrogen atoms are generated by adsorption and dissociation of the gaseous species. In aqueous environments, hydrogen atoms are produced by electrochemical reactions. In both cases, some of the hydrogen atoms diffuse through the metal sample and are then oxidized t
46、o hydrogen cations on exiting from the other side of the metal in the oxidation cell.A palladium coating is sometimes applied to one or both sides of the membrane following initial removal of oxide films. A palladium coating on the charging face of the membrane affects the sub-surface hydrogen conce
47、ntration in the substrate and the measured permeation current. It is important to verify that the calculated diffusivity is not influenced by the coating. Palladium coating is particularly useful for gaseous charging.5.3 The environment and the electrode potential on the oxidation side of the membra
48、ne are selected so that the metal is either passive or immune to corrosion. The background current established prior to hydrogen transport is steady, and small compared to the hydrogen atom oxidation current. ISO 2014 All rights reserved 3BS EN ISO 17081:2014ISO 17081:2014(E)5.4 The electrode potent
49、ial of the sample in the oxidation cell is controlled at a value sufficiently positive to ensure that the kinetics of oxidation of hydrogen atoms are limited by the flux of hydrogen atoms, i.e. the hydrogen atom oxidation current density is transport limited.NOTE Palladium coating of the oxidation side of the sample can enhance the rate of oxidation and thereby enable attainment of transport-limited oxidation of hydrogen atoms at less positive potentials than for the uncoated sample.5.5 The oxidation current is mon
