1、BRITISH STANDARD BS EN ISO 12687:1998 Metallic coatings Porosity tests Humidsulfur (flowers of sulfur) test The European Standard EN ISO 12687:1998 has the status of a British Standard ICS 25.220.40BSEN ISO 12687:1998 This British Standard, having been prepared under the direction of the Sector Boar
2、d for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 May 1998 BSI 04-1999 ISBN 0 580 29672 5 National foreword This British Standard is the English language version of ENISO12687:1998. It is identical with ISO12687:1996. The UK participa
3、tion in its preparation was entrusted to Technical Committee STI/37, Methods of test for metallic and related coatings, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals
4、 for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. 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 CENE
5、LEC standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue
6、 under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their corre
7、ct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN ISO title page, page 2, the ISO title page, page ii, pages 1 to 6, aninsideback cover and
8、 a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSENISO12687:1998 BSI 04-1999 i Contents Page National forew
9、ord Inside front cover Foreword 2 Foreword ii Text of EN ISO 12687 1ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 12687 March1998 ICS25.220.40 Descriptors: See ISO document English version Metallic coatings Porosity tests Humid sulfur (flowers of sulfur) test (ISO 12687:1996) Revt
10、ements mtalliques Essais de porosit Essai la fleur de soufre par voie humide (ISO 12687:1996) Metallische berzge Prfung der Porositt Na-Schwefelverfahren (mitSchwefelblte) (ISO 12687:1996) This European Standard was approved by CEN on 26 February 1998. CEN members are bound to comply with the CEN/CE
11、NELEC 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 Central Secretariat or to any
12、 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 Central Secretariat has the same status as the official versions. CE
13、N members are the national standards bodies of Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de No
14、rmalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 12687:1998 EENISO 12687:1998 BSI 04-1999 2 Foreword The text of the Intern
15、ational Standard from Technical Committee ISO/TC 107 “Metallic and other inorganic coatings” of the International Organization for Standardization (ISO) has been taken over as an European Standard by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings”, the secretariat of which is
16、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 September1998, and conflicting national standards shall be withdrawn at the latest by September1998. According to the CEN/CENELEC Inter
17、nal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland a
18、nd the UnitedKingdom. Endorsement notice The text of the International Standard ISO12687:1996 has been approved by CEN as a European Standard without any modification. NOTENormative references to International Standards are listed in Annex ZA (normative). Contents Page Foreword 2 1 Scope 1 2 Normati
19、ve references 1 3 Definitions 1 4 Principle 2 5 Summary of method 2 6 Reagents 2 7 Apparatus 2 8 Test specimen preparation 3 9 Procedure 3 10 Examination and evaluation of specimens 5 Annex A (informative) Significance and use 6 Annex B (informative) Bibliography 6 Annex ZA (normative) Normative ref
20、erences to international publications with their relevant European publications Inside back cover Figure 1 Typical test equipment arrangement 5EN ISO 12687:1998 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS
21、O 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. International organizations, gove
22、rnmental 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. Draft International Standards adopted by the technical committees are circulated to th
23、e member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO 12687 was prepared by Technical Committee ISO/TC107, Metallic and other inorganic coatings, Subcommittee SC7, Corrosion tests. Annex A
24、 and Annex B of this International Standard are for information only. Descriptors: Coatings, metal coatings, surface properties, tests, determination, porosity, imperfections.EN ISO 12687:1998 BSI 04-1999 1 1 Scope This International Standard specifies a method of revealing discontinuities and poros
25、ity in metallic coatings, where they penetrate the coating layer or layers down to a silver, copper or copper-alloy substrate. This method is especially useful for coatings consisting of single or combined layers of any coating that does not significantly tarnish in a reduced-sulfur atmosphere, such
26、 as gold, nickel, tin, tin-lead palladium and their alloys. This test method is designed to show whether or not the coating meets the requirement concerning an acceptable porosity level specified by the user. The value specified is usually determined by users experience to be acceptable for the inte
27、nded application. Recent reviews of porosity testing and test methods can be found in the literature 1, 2. An ISO general guide to porosity tests for metallic and other inorganic coatings is available as ISO10308:1995, Metallic coatings Review of porosity tests. 2 Normative references The following
28、standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encourage
29、d to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 2079:1981, Surface treatment and metallic coatings General classification of terms. ISO 2080:1981, Electro
30、plating and related processes Vocabulary. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. 3 Definitions For the purposes of this International Standard, the following definitions apply (other relevant definitions can be found in ISO2079 and ISO2080). 3.1 corrosion
31、products chemical products, derived from the substrate that usually protrude from the surface at discontinuities. The chemical reaction products form during the test and can be readily examined after the test exposure. They cannot be readily removed by mild air dusting see clause 10, item b) 2 3.2 d
32、iscontinuity any opening through an otherwise continuous coating. Typically the openings are pores or cracks in the coating. They may also be voids or breaks in the coating caused by mechanical damage such as scratches or non-conductive inclusions in the basis materials 3.3 measurement area in this
33、method, that portion or portions of the surface that is examined for the presence of porosity. The measurement area may be indicated on the drawings of the parts or by the provision of suitably marked samples 3.4 metallic coatings autocatalytic coatings, chemical (non-electrolytic) platings, claddin
34、gs, electroplatings and hot-dip coatings applied to the substrate. The coating may comprise a single metallic layer or a combination of metallic layers 3.5 pore a hole, typically microscopic in size and randomly located, often with a circular shape, that penetrates through the coating to an underlyi
35、ng coating or the basis-metal 3.6 porosity the presence of any crack, discontinuity, hole or scratch in the coating that exposes a different underlying metal 3.7 significant surface that portion or portions of the coating surface that is essential to the serviceability or function of the part, or wh
36、ich can be the source of corrosion products or tarnish films that interfere with the function of the part. For many coated products, the significant surface is identical to the measurement area 3.8 tarnish the reaction products of copper or silver with oxygen or reduced sulfur (i.e. H 2 S and elemen
37、tal sulfur vapour, but not SO 2or other sulfur oxides). They consist of thin films or marks and spots that do not protrude significantly from the surface of the metallic finish (in contrast with corrosion products)EN ISO 12687:1998 2 BSI 04-1999 3.9 tarnish creepage movement of tarnish films across
38、the surface of the coating. The tarnish originates either from pores or cracks in the coating or from areas of bare basis metal near the measurement area (as in a cut edge). It is also called creep corrosion 3.10 underplate a metallic coating layer between the substrate and the topmost layer or laye
39、rs. The thickness of an underplate is usually greater than 1 4m. There may be more than one 4 Principle This test relies on the formation of basis metal or underplate sulfides and oxides, formed by reaction with sulfur vapour in a humid atmosphere and exposed through discontinuities in the metallic
40、coating. The sulfide corrosion products of both silver and copper and copper oxide form black or brown-coloured markings or spots that are readily observed by visual inspection. 5 Summary of method Test specimens are suspended over flowers of sulfur (powdered sulfur) in a container equipped with a v
41、ent and at controlled, elevated relative humidity and temperature. Elemental-sulfur vapour, which always exists in equilibrium with sulfur powder in a closed system, attacks any exposed copper, copper alloy, silver or silver alloy such as that found at the bottom of pores. Brown or black tarnish mar
42、ks or spots indicate porosity. Exposure periods may vary, depending on the extent of porosity to be revealed. This test involves tarnish or oxidation (corrosion) reactions in which the corrosion products delineate defect sites in coatings. The chemistry and properties of the corrosion products forme
43、d as a result of the test usually do not resemble those found in natural or service environments. Therefore, this test is not recommended for prediction of product performance unless correlation is first established with service experience. 6 Reagents 6.1 Purity The potassium nitrate used shall be o
44、f recognized analytical-reagent grade. The water used shall be distilled or deionized and have a conductivity not greater than 204S/cm (measured as specified in ISO3696). The sulfur shall be of commercial laboratory grade. 6.2 Potassium nitrate solution Prepare a saturated solution of potassium nitr
45、ate (KNO 3 ) by adding approximately200g of the reagent to approximately200ml of water (see6.1). NOTEThe saturated solution will contain undissolved potassium nitrate salt. This condition is necessary to achieve a constant-humidity atmosphere above the solution. 6.3 Dry reagent Sulfur, precipitated
46、(flowers of sulfur). 7 Apparatus 7.1 Test vessel, consisting of any convenient-sized transparent vessel of glass or acrylic resin (or any other material that it not affected by high humidity or sulfur), such as a glass desiccator of approximately10litre capacity. It shall have a lid or cover with an
47、 access hole capable of being plugged with a stopper. The hole shall be large enough to allow the insertion of the humidity sensor with a remote read-out device into the vessel. The stopper shall contain a1mm to4mm diameter hole to serve as a vent. 7.2 Sample supports, designed as holders or hangers
48、 and made from material such as glass, acrylic resin or polypropylene which will not be affected by sulfur or high humidity, and arranged so that the test specimen will be at least75mm distance from the humidity-controlling solution and the sulfur powder (see7.3). The test specimen shall also be at
49、least25mm from the vessel walls and at least10mm from other test specimen and other surfaces. Do not use a desiccator plate as a primary support; it may be used as an under-support. The fixture and any supports shall not cover more than20% of the vessels cross-sectional area so that air movement (convection) within the vessel shall not be restricted during the test. 7.3 Glass dish, consisting of a petri or other shallow dish approximately150mm in diameter to hold powdered sulfur. The dish may be supported above the constant-hum
