1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-21921-5 SANS 3613:2008Edition 2 ISO 3613:2000Edition 2SOUTH AFRICAN NATIONAL STANDARD Chromate conversion coatings on zinc, cadmium, alumi
4、nium-zinc alloys and zinc-aluminium alloys Test methods This national standard is the identical implementation of ISO 3613:2000 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191
5、 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 3613:2008 Edition 2 ISO 3613:2000 Edition 2 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 107, Metallic and other inorganic coatings, in
6、accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in November 2008. This SANS document supersedes SABS ISO 3613:1980 (first edition). Reference numberISO 3613:2000(E)ISO 2000INTERNATIONALSTANDARDISO3613Sec
7、ond edition2000-06-15Chromate conversion coatings on zinc,cadmium, aluminium-zinc alloysand zinc-aluminium alloys Test methodsCouches de conversion au chromate sur zinc, cadmium et alliagesdaluminium-zinc et de zinc-aluminium Mthodes dessaiSANS 3613:2008This s tandard may only be used and printed by
8、 approved subscription and freemailing clients of the SABS .ISO 3613:2000(E)PDF disclaimerThis PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall notbe edited unless the typefaces which are embedded are licensed to and in
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11、se inform the Central Secretariat at the address given below. ISO 2000All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronicor mechanical, including photocopying and microfilm, without permission in writing f
12、rom either ISO at the address below or ISOs member bodyin the country of the requester.ISO copyright officeCase postale 56 Gb7 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.chWeb www.iso.chPrinted in Switzerlandii ISO 2000 All rights reservedSANS 3613:2008This s tan
13、dard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 3613:2000(E) ISO 2000 All rights reserved iiiForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISOmember bodies). The work of pre
14、paring International Standards is normally carried out through ISO technicalcommittees. Each member body interested in a subject for which a technical committee has been established hasthe right to be represented on that committee. International organizations, governmental and non-governmental, inli
15、aison with ISO, also take part in the work. ISO collaborates closely with the International ElectrotechnicalCommission (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
16、 Standards adopted by the technical committees 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 International Standard
17、 may be the subject ofpatent rights. ISO shall not be held responsible for identifying any or all such patent rights.International Standard ISO 3613 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganiccoatings, Subcommittee SC 2, Methods of inspection and coordination of test
18、 methods.This second edition cancels and replaces the first edition (ISO 3613:1980), which has been technically revised.SANS 3613:2008This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .SANS 3613:2008This s tandard may only be used and printed by
19、 approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO 3613:2000(E) ISO 2000 All rights reserved 1Chromate conversion coatings on zinc, cadmium, aluminium-zincalloys and zinc-aluminium alloys Test methodsWARNING This International Standard calls for the use of substan
20、ces and/or procedures that can beinjurious to health if adequate precautions are not taken. It refers only to technical suitability and in no wayabsolves either the designer, the producer, the supplier or the user from statutory and all other legalobligations relating to health and safety at any sta
21、ge of manufacture or use.1 ScopeThis International Standard specifies methods for the determination of theGbe presence of colourless1)chromate conversion coatings;Gbe presence and quantity of hexavalent chromium in colourless and coloured coatings on zinc, cadmium,aluminium (55 % mass fraction)-zinc
22、 and zinc-aluminium (5 % mass fraction) alloys;Gbe total chromium content per unit area on zinc and cadmium;Gbe mass per unit area of both colourless and coloured coatings;Gbe satisfactory adhesion of chromate conversion coatings;Gbe quality of chromate coating.These methods are applicableGbe to col
23、ourless and coloured chromate conversion coatings containing tri- and hexavalent chromium in varyingproportions and produced by either chemical or electrochemical processes;Gbe only to chromate coatings that are free from any supplementary coatings such as oil, water or solvent-basedpolymers or wax.
24、1) The application of very thin, colourless, practically invisible chromate conversion coatings is frequently called “passivation“,while the application of thicker, coloured chromate conversion coatings is often called “chromating“. The term passivation is notcorrect and is, therefore, not recommend
25、ed.SANS 3613:2008This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 3613:2000(E)2 ISO 2000 All rights reserved2 Normative referencesThe following normative documents contain provisions which, through reference in this text, constitute provis
26、ions ofthis International Standard. For dated references, subsequent amendments to, or revisions of, any of thesepublications do not apply. However, parties to agreements based on this International Standard are encouraged toinvestigate the possibility of applying the most recent editions of the nor
27、mative documents indicated below. Forundated references, the latest edition of the normative document referred to applies. Members of ISO and IECmaintain registers of currently valid International Standards.ISO 3892:2000, Conversion coatings on metallic materials Determination of coating mass per un
28、it area Gravimetric methods.ISO 4520:1981, Chromate conversion coatings on electroplated zinc and cadmium coatings.ISO 9227:1990, Corrosion tests in artificial atmospheres Salt spray tests.IEC 60068-2-30:1980, Environmental testing Part 2: Tests. Test Db and guidance: Damp heat, cyclic (12 + 12hour
29、cycle).3 ReagentsDuring the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilledwater or water of equivalent purity.3.1 Test solution A (see 5.2).Dissolve 1 mg of diphenylcarbazide in a mixture of 60 ml glacial acetic acid and 40 ml distilled water c
30、ontained in abeaker. Add 15 ml of concentrated hydrochloric acid (relative density 1,18), stir and add slowly 30 ml of sodiumhypochlorite solution (10 % to 15 % available chlorine). Add 5 ml of hydrogen peroxide (30 %) slowly withcontinuous stirring. Leave the solution in the open beaker for 24 h in
31、 a fume cupboard, to allow excess chlorine toescape, before use.NOTE The solution does not deteriorate with age and therefore can be kept in a bottle with a loosely fitting glass stopperover a period of several months.3.2 Test solution B (see 5.3).Dissolve 50 g of lead acetate trihydrate (CH3COO)2Pb
32、.3H2O in 1 l of distilled or de-ionized water. Ensure that thepH of the solution is between 5,5 and 6,8 as prepared. If the pH of the solution is outside this range, discard thesolution and obtain a new supply of lead acetate.Any white precipitate formed during the initial preparation of the solutio
33、n may be dissolved by small additions ofglacial acetic acid, provided that the pH is not reduced to a value below 5,5. Discard the stock solution if the whiteprecipitate does not disappear.3.3 Test solution C (see 5.5).Dissolve 0,4 g of diphenylcarbazide in a mixture of 20 ml acetone and 20 ml ethan
34、ol (96 %). After dissolution, add20 ml of 75 % orthophosphoric acid solution and 20 ml of distilled water. Prepare this solution not more than 8 hprior to use.3.4 Test solution D (see 5.6 and 5.7).Dissolve 0,50 g of diphenylcarbazide in 50 ml of acetone. Dilute slowly, while stirring, with 50 ml of
35、water (rapidmixing can result in precipitation of diphenylcarbazide).For maximum stability, store the solution under refrigeration in an amber-coloured glass bottle.SANS 3613:2008This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 3613:2000(E
36、) ISO 2000 All rights reserved 33.5 Sulfuric acid, diluted 1 + 3.Slowly add 1 volume of concentrated sulfuric acid (relative density 1,84) to 3 volumes of water.3.6 Ammonium persulfate (NH4)2S2O8.3.7 Sodium hydroxide (NaOH), (240 g/l) solution.3.8 Silver nitrate (AgNO3), 17 g/l solution.3.9 Potassiu
37、m dichromate (K2Cr2O7), standard solution.Dilute to 1 000 ml 2 ml of standard volumetric potassium dichromate solution (4,9 g/l).3.10 Phosphate buffer solutionDissolve 55 g of sodium dihydrogen orthophosphate monohydrate (NaH2PO4.H2O) in 100 ml water.4 Apparatus4.1 Photoelectric absorptiometer (colo
38、rimeter), with a filter having a mean transmission of 520 nm. Theabsorptiometer shall be used with an absorption cell of optical path length 10 mm.4.2 Spectrophotometer, with wavelength set at 540 nm. The spectrophotometer shall be used with anabsorption cell of optical path length 10 mm.5 Test meth
39、ods5.1 GeneralThe test surface, prior to the following tests, shall be free of all contaminants, finger prints and other extraneousstains. If the surface is coated with thin oil, it shall be removed prior to the test by degreasing using a suitablesolvent at room temperature (not exceeding 35 C). For
40、 test purposes, the samples shall not be subjected to forceddrying at temperatures in excess of 35 C. Treatment in alkaline solutions shall not be performed as chromateconversion coatings are broken down by alkalis.The test methods fora) the presence of a colourless chromate coating on zinc, cadmium
41、 and aluminium-zinc alloy,b) the presence of hexavalent chromium in both coloured and colourless chromate coatings,c) the determination of hexavalent chromium content andd) the determination of total chromium contentaregivenin5.2to5.7.The tests shall be carried out within the following time limits:G
42、be minimum 24 h after the application of the chromate conversion coating for all tests (5.2 to 5.10);SANS 3613:2008This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 3613:2000(E)4 ISO 2000 All rights reservedGbe maximum3dfortestsspecifiedin5
43、.2to5.52);Gbe maximum 30 d for tests specified in 5.6 and 5.7.The test methods fora) the determination of mass per unit area of chromate conversion coatings,b) adhesion by abrasion andc) the evaluation of the quality of chromate layerare given in 5.8, 5.9 and 5.10, respectively.5.2 Test for the pres
44、ence of a colourless chromate coating on zincApply 1 drop of test solution A (3.1) to the chromated zinc surface. The formation of a red or red-violet colour in thedrop shall be deemed to indicate the presence of chromate film.5.3 Test for the presence of a colourless chromate coating on zinc and ca
45、dmiumPlace 1 drop of test solution B (3.2) on the surface to be tested.In the case of a zinc substrate, observe the appearance of the spot for 3 min. The formation of a dark or black stainat least 1 min after the application of the test solution shall be deemed to indicate the presence of a colourle
46、sschromate conversion coating.Black stain formation after more than 3 min can be indicative of the presence of supplementary coatings, such aswax or oil.In the case of a cadmium substrate, observe the appearance of the spot for 1 min. The formation of a dark or blackstain at least 5 s after the appl
47、ication of the test solution shall be deemed to indicate the presence of a colourlesschromate conversion coating.Black stain formation after more than 1 min can be indicative of the presence of supplementary coatings, such aswax or oil.For comparison purposes, test an untreated surface similarly. Un
48、treated zinc and cadmium surfaces or thesurfaces that have been treated for chromate conversion coating but do not have continuous coating will react withthe lead acetate solution to form a black stain on the untreated or bare zinc and cadmium surfaces almostimmediately, within 2 s to 5 s, after the
49、 application of the test solution.NOTE 1 Because of the sensitivity of the method, the test is considered to be a quality control tool for the processor. Itemswith damaged chromate layers should not be tested by this method.NOTE 2 Chromate conversion coatings exposed to temperatures above 60 C will have considerably reduced resistance tocorrosion in the accelerated test method (5.10), and will show black stain in less than 60 s on zinc, and less than 5 s oncadmium.NOTE 3 No significance should be placed upon any differences in the reacti
