1、BRITISH STANDARD BS EN ISO 15721:2001 Metallic coatings Porosity tests Porosity in gold or palladium coatings by sulfurous acid/sulfur dioxide vapour The European Standard EN ISO 15721:2001 has the status of a British Standard ICS 25.220.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY CO
2、PYRIGHT LAWBS EN ISO 15721:2001 This British Standard, having been prepared under the direction of the Sector Committee for Materials and chemicals, was published under the authority of the Standards Committee and comes into effect on 15 July 2001 BSI 07-2001 ISBN 0 580 37870 5 National foreword Thi
3、s British Standard is the official English language version of EN ISO 15721:2001. It is identical with ISO 15721:2000. The UK participation in its preparation was entrusted to Technical Committee STI/37, Methods of test for metallic and related coatings including corrosion tests, which has the respo
4、nsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their correspo
5、nding European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catal
6、ogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the tex
7、t; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cov
8、er, an inside front cover, the EN ISO title page, the EN ISO Foreword page, the ISO title page, pages ii to v, a blank page, pages 1 to 7, the Annex ZA page, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendm
9、ents issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM ENISO15721 April2001 ICS25.220.40 Englishversion MetalliccoatingsPorositytestsPorosityingoldorpalladium coatingsbysulfurousacid/sulfurdioxidevapour(ISO 15721:2001) RevtementsmtalliquesEssaisdeporositPo
10、rosit desrevtementsdoroudepalladiumparessailacide sulfureux/vapeurdedioxidedesoufre(ISO15721:2001) MetallischeberzgePorenprfungenBestimmungdes PorenanteilsinGoldoderPalladiumberzgenmit schwefligerSure/Schwefeldioxiddampf(ISO15721:2001) ThisEuropeanStandardwasapprovedbyCENon15April2001. CENmembersare
11、boundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. This
12、EuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Czec
13、hRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2001CEN A
14、llrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO15721:2001EgaPe2 INESO5112702:01 Foreword ThetextoftheInternationalStandardISO15721:2001hasbeenpreparedbyTechnical CommitteeISO/TC107“Metallicandotherinorganiccoatings“incollaborationwithTechnical Commit
15、teeCEN/TC262“Metallicandotherinorganiccoatings“,thesecretariatofwhichis heldbyBSI. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublication ofanidenticaltextorbyendorsement,atthelatestbyOctober2001,andconflictingnational standardsshallbewithdrawnatthelatestbyOctober2001. Acco
16、rdingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsof thefollowingcountriesareboundtoimplementthisEuropeanStandard:Austria,Belgium, CzechRepublic,Denmark,Finland,France,Germany,Greece,Iceland,Ireland,Italy, Luxembourg,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandtheU
17、nited Kingdom. Endorsementnotice ThetextoftheInternationalStandardISO15721:2001wasapprovedbyCENasaEuropean Standardwithoutanymodification. NOTE:NormativereferencestoInternationalStandardsarelistedinannexZA(normative). ENISO15721:2001 Reference number ISO 15721:2001(E) INTERNATIONAL STANDARD ISO 1572
18、1 First edition 2001-04-15 Metallic coatings Porosity tests Porosity in gold or palladium coatings by sulfurous acid/sulfur dioxide vapour Revtements mtalliques Essais de porosit Porosit des revtements dor ou de palladium par essai lacide sulfureux/vapeur de dioxyde de soufre ENISO15721:2001 ISO 127
19、51:(1002)E ii ENISO15721:2001 ISO 12751:(1002)Eiii Contents Page Foreword.iv Introduction.v 1 Scope 1 2 Normative references 1 3 Terms and definitions .2 4 Apparatus .2 5 Reagents.2 6 Safety hazards2 7 Procedure .3 8 Examination4 9 Precision.5 10 Test report 5 Annex A (informative) Significance and
20、use 6 Bibliography7 ENISO15721:2001 ISO 12751:(1002)E 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 committee
21、s. 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. ISO collaborates closely with the Inter
22、national Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodi
23、es 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 International Standard may be the subject of patent rights. ISO shall not be held responsible for id
24、entifying any or all such patent rights. International Standard ISO 15721 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings, Subcommittee SC 7, Corrosion tests. Annex A of this International Standard is for information only. ENISO15721:2001 ISO 12751:(1002)Ev Intr
25、oduction The test method makes use of concentrated sulfurous acid (H 2 SO 3 ), which emits sulfur dioxide (SO 2 )g a s according to the equilibrium reaction: H 2 SO 3 =S O 2 +H 2 O WARNING The sulfur dioxide gas that is released by the sulfurous acid is toxic, corrosive and irritating. The sulfurous
26、 acid shall only be handled and used in a fume cupboard. Prior to starting the test, suitable preparation shall be made to dispose of approximately 200 ml to 500 ml of sulfurous acid used in the test. The procedure is similar to one first proposed by Lee and Ternowski 4 . Exposure periods may vary,
27、depending upon the degree of porosity to be revealed. Reaction of the gas with a corrodible base metal at pore sites produces reaction products that appear as discrete spots on the gold or palladium surface. Individual spots are counted with the aid of a lens or low-power stereomicroscope. This test
28、 method is suitable for coatings containing 95 % or more of gold or palladium on substrates of copper, nickel and their alloys which are commonly used in electrical contacts. This test is considered destructive because it reveals the presence of porosity by contaminating the surface with corrosion p
29、roducts and it undercuts the coating at pore sites or at the boundaries of the unplated areas. Any parts exposed to this test shall not be placed in service. The present test method is capable of detecting virtually all porosity or other defects that could participate in corrosion reactions with the
30、 substrate or underplate. The test is rapid, simple and inexpensive. In addition, it can be used on contacts with a complex geometry such as pin-sockets (it may be useful to open contact structures with deep recesses to permit reaction of the sulfur dioxide with the interior significant surfaces). E
31、NISO15721:2001 ENISO15721:2001 INTENRATIONAL TSANDADR ISO 12751:(1002)E1 Metallic coatings Porosity tests Porosity in gold or palladium coatings by sulfurous acid/sulfur dioxide vapour WARNING This International Standard does not purport to address all of the safety concerns, if any, associated with
32、 its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see clause 6. 1 Scope This test method covers equipment and metho
33、ds for determining the porosity of gold or palladium coatings, particularly electrodeposits and clad metals used on electrical contacts. It is designed to show whether the porosity level is less than or greater than a given value which by experience is considered by the user to be acceptable for the
34、 intended application. This porosity test involves corrosion reactions in which the products delineate defect sites in coatings. Since the chemistry and properties of these products may not resemble those found in natural or service environments this test cannot be recommended for the prediction of
35、the electrical performance of contacts unless correlation is first established with service experience. This test is intended to be used for quantitative descriptions of porosity (such as number of pores per unit area or per contact) on coatings that have a sufficiently low pore density so that the
36、corrosion sites are well separated and can be readily resolved. As a general guideline this can be achieved for pore densities up to about 100/cm 2 .A b o v e this value the tests are useful for the qualitative detection and comparisons of porosity. A variety of other porosity testing methods are de
37、scribed in the literature 5,6 . Other ISO porosity test methods are described ISO 10308, ISO 12687, ISO 14647 and ISO 15720. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For da
38、ted references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For un
39、dated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 2064, Metallic and other inorganic coatings Definitions and conventions concerning the measurement of thickness. ISO 2079, Sur
40、face treatment and metallic coatings General classification of terms. ISO 2080, Electroplating and related processes Vocabulary. ISO 10308, Metallic coatings Review of porosity tests. ENISO15721:2001 ISO 12751:(1002)E 2 3 Terms and definitions For the purposes of this International Standard, the ter
41、ms and definitions given in ISO 2064, ISO 2079, ISO 2080 and ISO 10308 as well as the following apply. 3.1 corrosion products those reaction products emanating from the pores that protrude from, or are otherwise attached to, the coating surface after a vapour test exposure 3.2 metallic coatings incl
42、udes platings, claddings or other metallic layers applied to the substrate NOTE The coatings can comprise a single metallic layer or a combination of metallic layers. 3.3 porosity presence of any discontinuity, crack or hole in the coating that exposes a different underlying metal 4 Apparatus 4.1 Te
43、st chamber, of any convenient size, made of glass or acrylic resin with a gas-tight lid, such as a glass desiccator of 9 l to 10 l, capacity. The ratio of chamber volume in cubic centimeters to the generating solution (sulfurous acid) surface area in square centimeters shall not exceed 25 1. 4.2 Spe
44、cimen holders, or supports, of glass, polytetrafluoroethylene, or other inert materials. It is essential that the specimens be so arranged that they do not impede gas circulation. Specimens shall not be closer than 25 mm from the wall and 75 mm from the solution surface. The measurement areas of the
45、 specimens shall be at least 12 mm apart. NOTE Do not use a porcelain plate or any other structure that would cover more than 30 % of the liquid surface cross- sectional area. This is to ensure that movement of air and vapour within the vessel will not be restricted during the test. 4.3 Stereomicros
46、cope, having a 10 magnification shall be used for pore counting. In addition a movable source of illumination capable of giving oblique lighting on the specimen surface is required. An eyepiece is recommended for the convenience in locating the contact area or other significant measurement areas. 5
47、Reagents Sulfurous acid (H 2 SO 3 ), “analytical grade reagent“, or better, in individual well-sealed bottles. 6 Safety hazards 6.1 Carry out these test procedures in a clean, working fume cupboard. The SO 2 g a st h a ti se m i t t e di st o x i c , corrosive, and irritating. 6.2 Use caution howeve
48、r, when actually performing the tests that the drafts often found in fume cupboards do not cause significant cooling of the chamber walls which may lead to condensation of water and acceleration of the test. It is often convenient to enclose the reaction vessel in a box with a loose-fitting cover and to keep the box in a fume cupboard during the test. 6.3 Observe normal precautions in handling corrosive acids. In parti
