1、DEUTSCHE NORM April 1995 c (u ._ - L m i Qi U 3 f z c p 1 .- 3 G? 2 $ z 2 c2 r C (II ._ ._ E a O Q (u L ._ L r c 3 r ._ 3 U 0 3 711 L L (u Q 2i 2 P 711 c m (II (II .- f - O m Q O z c L o Metallic and non-organic coatings on metallic substrates Saline droplets corrosion test (SD test) (IS0 4536 : 198
2、5) English version of DIN EN IS0 4536 DIN - EN IS0 4536 This standard incorporates the English version of Is0 4536. ICs 25.220.40; 77.060 Descriptors: Metal coatings, non-organic coatings, corrosion test, SD test. Metallische und anorganische berzge auf metallischen Grundwerkstoffen; Salztrpfchen-Ko
3、rrosionsprfung (SD-Versuch) (IS0 4536: 1985) European Standard EN IS0 4536: 1995 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been published in accordance with a decision taken by CEN/TC 262 to adopt, without alteration, International S
4、tandard IS0 4536 as a European Standard. The responsible German body involved in its preparation was Technical Committee Korrosion und Korrosionsschutz of the Normenausschu Materialprfung (Materials Testing Standards Committee). Standards referred to See References and Annex ZA. EN comprises 7 pages
5、. Beuth Verlag GmbH, Berlin, has the exclusive right of sale for German Standards (DIN-Normen). DIN EN IS0 4536 Engl. Price group 6 10.95 Sales No. 11 06 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 4536 January 1995 ICs 25.220.40; 77.060 Descriptors: Metal coatings, non-organic coatings
6、, corrosion test, SD test. English version Metallic and non-organic coatings on metallic substrates Saline droplets corrosion test (SD test) (IS0 4536 : 1985) Revtements mtalliques et non orga- niques sur bases mtalliques; essai de cor- rosion aux gouttelettes salines (Essai SD) trpfchen-Korrosionsp
7、rfung (SD-Ver- (IS0 4536 : 1985) Metallische und anorganische berzge auf metallischen Grundwerkstoffen; Salz- such) (IS0 4536: 1985) This European Standard was approved by GEN on 1994-10-03 and is identical to the IS0 Standard as referred to. CEN members are bound to comply with the CENKENELEC Inter
8、nal 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 CEN member
9、. 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. CEN members a
10、re the national standards bodies of Austria, Belgium, 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 Normalisation Europisches Ko
11、mitee fr Normung Central Secretariat: rue de Stassart 36, 8-1050 Brussels O 1995. Copyright reserved to all CEN members. Ref. No. EN IS0 4536: 1995 E Page 2 EN IS0 4536 : 1995 Foreword International Standard IS0 4536: 1985 Metallic and non-organic coatings on metallic substrates; saline droplets cor
12、rosion test (SD test) which was prepared by ISOTC 107 Metallic and other inorganic coatings of the International Organization for Standardi- zation, has been adopted by Technical Committee CENTTC 262 Protection of metallic materials against corrosion as a European Standard. This document was submitt
13、ed for Formal Vote and adopted as a European Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by July 1995 at the latest. In accordance with the CENKENELEC In
14、ternal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of th
15、e International Standard IS0 4536: 1985 was approved by CEN as a European Standard without any modifica- tion. NOTE: Normative references to international publications are listed in Annex ZA (normative). Page 3 EN IS0 4536: 1995 O Introduction 1 Scope and field of application 0.1 This test differs s
16、ignificantly from that specified in IS0 3768, Metallic coatings - Neutral salt spray test (NSS test), although the fields of application of the two tests are similar and their results are often comparable. In the saline droplets corrosion test, a pattern of discrete droplets is pro- duced by sprayin
17、g the specified test solution on to the surfaces being tested. 0.2 The droplets test may therefore have advantages for testing some conversion coatings which may, in continuous leaching, undergo changes which do not occur in their usual conditions of service. For some applications, the droplets test
18、 may be more severe than the continuous spray test since the corrosion processes in static drops may cause more intense local action than that produced by a continuous moving mois- ture film. The method has advantages in needing only simple, easily controlled apparatus and in being applicable to art
19、icles of complex shape. 0.3 The method of corrosion by a pattern of discrete droplets has been used with several solutions for tests intended to assess the resistance of a coating to particular environments. Only one test solution is specified in this International Stan- dard. It contains the major
20、mineral constituents of sea-water and has advantages in that droplets of the solution do not easily dry out and that, for some purposes, simulation of the effects of sea-spray may be useful. However, other solutions may be given in specifications for materials and products. 0.4 In many instances, th
21、ere is no direct relation between the results of an accelerated corrosion test and the resistance to corrosion in other media, because several factors which influence the progress of corrosion, such as the formation of protective films, vary greatly with the conditions encountered. ,The results obta
22、ined in the test should not, therefore, be regarded as a direct guide to the corrosion resistance of the tested materials in all environments where these materials may be used. Furthermore, performance of different materials in the test cannot always be taken as a direct guide to the relative corros
23、ion resistance of these materials in service. 1.1 This International Standard specifies the test solution, the apparatus and the procedure for a saline droplets corrosion test for assessment of the quality of metallic and non-organic coatings, made in accordance with the requirements of coating or p
24、roduct specifications on metallic substrates. 1.2 The method of test specified is suitable for detecting defects and discontinuities in metal coatings cathodic to the underlying metal. It is also suitable for chemical or elec- trochemical conversion coatings such as those obtained by chromate and ph
25、osphate treatments. The method is not suitable for testing coatings intended for the more severe types of service. 1.3 The type and number of test specimens, the exposure periods to be used for a particular product and the interpreta- tion of results are not specified in this International Standard.
26、 Such details should be given in the appropriate materials or coating specification. 2 References IS0 483, Plastics - Small enclosures for conditioning and testing at relative humidities maintained by aqueous solutions. I IS0 1462, Metallic coatings - Coatings other than those anodic to the basis me
27、tal - Accelerated corrosion tests - Method for the evaluation of the results. IS0 4540, Metallic coatings - Coatings cathodic to the substrate - Rating of electroplated test specimens subjected to corrosion tests. 3 Principle Spraying of the test specimens with a neutral salt solution, storing in co
28、nditions of high humidity, respraying only when it is needed to maintain the pattern of droplets. NOTE - The regular flow of new solution over the surfaces under test, such as occurs in the continuous salt spray test, does not take place. li At present at the stage of draft. (Revision of ISO/R 483-1
29、966.) Page 4 EN IS0 4536: 1995 Sodium chloride i NaCl) Magnesium chloride (MgCIz) Magnesium sulfate (MgSOq) Calcium chloride CaC12) Potassium chloride Sodium hydrogen carbonate iNaHCO3) Sodium bromide (NaBr) (KCI) r 4. Test solution see the table) Using only reagents of recognized analytical grade a
30、nd only distilled or demineralized water of pH 6.5 to 7,2, prepare a sol- ution, the composition of which is given in the table. Table - Composition of test solution Component I Concentration g/i 26,5 2,4 3,3 1,1 0,73 0.20 0,28 Filter the solution before use in order to remove any solid matter which
31、 might block the aperture of the spraying device. 5 Apparatus 5.1 Cabinet or other suitable container, in which the test specimens are exposed to air with relative humidity in the range 85 % to 95 % at 23 + 3 OC. The cabinet may be of any suit- able shape and dimensions. It shall be made of a corros
32、ion- resistant material (for example glass or plastics) so as to pre- vent the formation of corrosion products which might con- taminate the test specimens. The required relative humidity may be produced and maintained within the cabinet by placing on its base an open vessel con- taining water or a
33、saturated solution of salts (for example potassium chloride or potassium nitrate) which will not in- fluence the corrosion process, or by any other convenient means see IS0 483). Other conditions of temperature and humidity may be used by agreement between the parties concerned. In this case, the ag
34、reed test conditions shall be described in the test report. 5.2 Stands) or suppors), to hold the test specimens, made from non-metallic materials resistant to corrosion by the test solution (for example glass or plastics). 5.3 Means of producing a spray of fine droplets, compris- ing a container for
35、 the test solution, fitted with a suitable atomizing nozzle and provided with means of generating suf- ficient pressure to deliver spray from the nozzle. NOTES 1 A suitable design of hand-operated atomizer is shown in figure 1. Alternatively, a glass chromatographic spray-head is satisfactory for us
36、e in producing these fine droplets; suitable spray-heads of this type are available commercially. 2 The compressed air used for spraying shall be thoroughly filtered and free from traces of oil. 6 Test specimens 6.1 Select the number and type of test specimens, their shape and their dimensions accor
37、ding to the specification for the product or coating being tested. NOTE - The simultaneous exposure of control specimens for which the correlation between the test and service life has been established is often useful. 6.2 Unless otherwise specified, clean the test specimens before testing. Choose t
38、he method of cleaning appropriate to the nature of the surface and of the contaminants. Do not use abrasives on conversion coatings; for metallic coatings, the only permitted abrasive is a paste of pure magnesium oxide. Do not use solvents that are corrosive or which may deposit either corrosion-pro
39、moting or protective films. Take care to ensure that the test specimens are not recontaminated after cleaning by careless handling or in any other way. 6.3 If the test specimens are cut from a larger coated article, carry out the cutting in such a way that the coating is not damaged, especially in t
40、he area adjacent to the cut. Unless otherwise specified, protect the cut edges adequately by coating them with a suitable medium that is stable under the conditions of the test, such as paint, wax or tape. Take care to avoid contamination by swarf during cutting. 7 Method of exposure of test specime
41、ns 7.1 Place the test specimens on the stands) or support(s) (5.2) so that contact does not occur between individual specimens and so that test solution (clause 4) cannot run off from one test specimen on to another. 7.2 The surfaces to be tested may be inclined at any angle to the horizontal, provi
42、ded that a pattern of discrete droplets of solution, as described in 8.1, can be produced on them by spraying and retained on them for the necessary period. The limitation on the angle of inclination imposed by this require- ment depends to some extent on the nature of the surface being tested but i
43、s often negligible. 7.3 When the stands) or supportsJ are placed in the cabinet, the test specimens shall not come into contact with the walls of the cabinet or with any vessels placed therein to maintain the desired relative humidity. 8 Procedure 8.1 Lightly spray the test specimens with the test s
44、olution from the atomizer nozzle (see 5.3) so as to cover the entire surface to be tested with discrete droplets of solution. The spraying shall not be so heavy that the droplets coalesce to form a continuous film of solution on the surface. The size and distribution of droplets required are illustr
45、ated in figure 2. If the droplets coalesce at the first spraying, wash off and dry the test specimen before re-spraying . Page 5 EN IS0 4536 : 1995 When articles of complex shape are tested, it will usually be necessary to arrange for them to be supported in more than one position so that spray can
46、be directed conveniently at all surfaces to be tested and so that the droplet pattern can be seen. It may be difficult (see top row of figure 2) to see the droplet pattern on some surfaces because of their roughness or colour. In such instances, it is advantageous to make a trial spraying on a surfa
47、ce such as that of clean, smooth metal, glass or plastics material on which the droplets are easily seen and then to repeat with the surface to be tested the action seen to produce the required pattern. 8.2 Immediately after spraying, place the test specimens on the stands) (5.2) in the test cabinet
48、 (5.1) maintained at the specified relative humidity and temperature, taking precautions against sudden changes or local differences of temperature. 8.3 At least once during each working day, remove the test specimens from the cabinet and record the progress of any corrosion that has occurred. Minim
49、ize the time occupied by the inspection and do not allow the droplets to dry out. Do not disturb accumulations of salts and corrosion products. If at any inspection the droplets are seen to be diminishing in size or number, respray the test specimens to restore the droplet pattern specified in 8.1 9 Duration of tests The period of test shall be as designated by the specification for the coating or product being tested. Recommended periods of exposure are 2; 6; 24; 48; 96; 240; 480 and 720 h. 10 Treatment of test specimens after test At the end of the test
