1、CEN EN*IS0*4524- 3 95 m 3404589 0304295 142 A- 1 BRITISH STANDARD Metallic coatings - Test methods for electrodeposited gold and gold alloy coatings - Part 3. Electrographic tests for porosity The European Standard EN IS0 4524-3 : 1995 has the stah of a British Standard BS EN IS0 4524-3 : 1995 CEN E
2、N*ISO*4524- 3 95 M 3404587 0304297 TL5 M BS 6670 : Part 3 : 1986 Contents National foreword Committees responsible Methods 1. Scope and field of application 2. Cadmium sulfide paper test Page Inside front cover Back cover 3. Nioxime paper test 4. Dye-transfer paper test 1 5. Dye-transfer paper test
3、2 6. Electrographic gelatine film test 1 7. Test report 1 Page 1 2 2 2 3 National foreword This Part of BS 6670 has been prepared under the direction of the Surface Coatings (other than Paints) Standards Committee. It is identical with IS0 4524/3*-1985 Metallic coatings - Test methods for electrodep
4、osited gold and gold alloy coatings - Part 3: Electrographic tests for porosity prepared by Sub-committee 3, Electrodeposited coatings and related finishes of Technical Committee 107, Metallic and other non-organic coatings, of the International Organization for Standardization (IS01 with the active
5、 participation and approval of the UK. In 1994 the European Committee for Standardization (CEN) accepted IS0 45243 : 1985 as European Standard EN IS0 4524-3 : 1994, As a consequence of implementing the European Standard this British Standard is renumbered as BS EN 45243 : 1995 and any reference to B
6、S 6670 : Past 3 should be read as a reference to BS EN IS0 45243 : 1995. A number of the Parts of BS 6670 are intended to replace certain of the appendices of BS4292 : 1968, Electroplated coatings of gold and gold alloy. Now that the test methods required for this purpose have been published, BS 429
7、2 : 1968 is being revised. Upon completion of the revision it will no longer contain the texts of test methods and BS 4292 1968 will be withdrawn. At present, the following Parts of BS 6670 have been published. Part 1 Determination of coating thickness Part 2 Environmental tests Part 3 ,Electrograph
8、ic tests for porosity Part 4 Determination of gold content Part 5 Adhesion tests Further Parts of this standard will be prepared, if required. Terminology and conventions. The text of the international standard as been approved as suitable for publication as a British Standard without deviation. Som
9、e terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. In British
10、 Standards it is current practice to use the symbol L for litre rather than I and to use the spelling sulphur, etc. instead of sulfur, etc. Wherever the words this part of IS0 4524 appear, referring to this standard, they should be read as this Part of Bs 6670. This Part describes methods of test on
11、ly and should not be used or quoted as a specification. Reference to this Part should state that the method of test used is in accordance with BS 6670 : Part 3. Compliance with sBritish Standard does not of itself confer immunity from legal obligations. *Corrected and reprinted March 1986. CEN EN*IS
12、O*Y524- 3 75 3404589 OLDLi298 951 EUROPEAN srmm NORME EUROPENIW EuROPmE NORM ENLSO 45243 January 1995 ICs 25.220.40 Descriptors: Metal cotaings, electrodeposited coatings, gold plating, decorative coatings, tests, porosity measurement, coatings, protective coatings, determination, porosity Engiish v
13、ersion Metallic coatings - Test methods for eleetxodeposited gold and gold alloy coatings - Part 3: Eleetrographie tests for porosity (IS0 45243 : 1985) Revtements mtalliques - Mthodes dessai des dpts lectrolytiques dor et dalliages dor - Partie 3: Dtermination lectrographique de la porosit Prfungen
14、 auf Porositt (IS0 4524-3 1985) (IS0 45243 : 19%) Metallische bexziige - Pruverfahren fr elektrolytisch abgeschiedene Uberzge aus Gold und Goldegierungen - Teil 3: Elektrografiiche This European Standard was approved by CEN on 199410-03. CEN members are bound to comply with the CENKENELEC Internal R
15、egulations 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 Centrai Secretariat or to any CEN member. Thi
16、s 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 are th
17、e national standards bodies of Austria, Belgium, Denmark, Finiand, 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 Komitee
18、 fur Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1995 Copyright reserved to ali CEN members Ref. No. EN IS0 45243 : 1995 E CEN EN*ISO*4524- 3 95 3404589 OLD4299 898 Page 2 EN IS0 4524-3 : 1995 A Foreword This European Standard has been taken over by the Technical Committee CEN
19、K 262, Protection of metallic materials against corrosion, from the work of ISO/C 107, Metallic and other inorganic coatings, of the International Organization for Standardization This document was submitted to the fonnal vote and was adopted by CEN as a European Standard. This European Standard sha
20、ll be given the status of a national standard, either by publication of an identical text or by endowment, at the latest by July 1995, and conflicting national standards shaii be withdrawn at the latest by July 1995. In accordance with the CENKENELEC Internal Reguations, the following countries are
21、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. mo. - CEN EN*IS0*4524- 3 75 3404587 OL04300 33T BS 6670 : Part 3 : 1986 British St
22、andard Methods of test for Electroplated gold and gold alloy coatings Part 3. Electrographic tests for porosity 1 Scope and field of application This part of IS0 4524 specifies five electrographic tests for assessing the porosity of electrodeposited gold and goid alloy coatings for engineering, and
23、decorative and protective purposes. 2 Cadmium sulfide paper test 2.1 Applicability This method is suitable for the examination of gold c$ating$ on copper. 2.2 Materials During the test, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equ
24、ivalent purity. 2.2.1 Cadmium sulfide paper. Use filter or duplicating paper of adequate wet strength, with a texture that will produce sharp and uniform electrograms. Soak the paper for 10 min in a fresh 10 % (mlrn) solution of cad- mium chloride hemipentahydrate (CdCI2.2,5 Hfl) containing 0,l % V/
25、V) of hydrochloric acid (HCI, e 1,16 to 1,18g/ml). Remove the excess solution with blotting paper. Allow the paper to dry partially and then immerse it in a fresh 50 g/l solution of sodium sulfide (Nafi) for 30 s, after which time the paper should be a uniform yellow colour (indicating complete prec
26、ipitation of cadmium sulfide, CdS). Wach the paper in running water for approximately 1 h, then hang it up to dry. 2.2.2 Moistened blotting paper. Soak a good quality white blotting paper in water and dry it to a degree that consistently produces sharply defined elec- trograms. 2.3 Procedure Lightly
27、 brush the electroplated coating to remove loose dust and debris, then degrease it in 1.1,l-trichloroethane vapour or other suitable solvent. Place a piece of the cadmium sulfide paper on the electroplated specimen (which acts as the anode). On the other face of the cadmium sulfide paper, place a pi
28、ece of the moistened blotting paper (2.2.21, followed by a high purity clean aluminium or stainless steel platen (which acts as the cathode). Compress the assembly so that the pressure between the cadmium sulfide paper and the specimen is uniform and between 1.4 and 1,7 MPa. While under compression,
29、 pass a smooth ripple-free d.c. current from a source not exceeding 12 V. Set the current density initialiy at 7.5 mA/cm2 of anode area and pass for 30 s. Allow the electrogram produced on the cadmium sulfide paper to dry. The presence of any defect in the electroplated coating is revealed by a corr
30、esponding brown stain on the paper. NOTE - If an overall black stain IS obtained in this test, either the elec trolyte content of the papers or the current density IS too high 3 Nioxime paper test 3.1 Applicability This method is suitable for the examination of gold coatings on undercoats of nickel
31、or tin-nickel alloy. 3.2 Materials During the test, use only reagents of recognized analytical grade and oniy distilled water or water of equivalent purity. Nioxime paper. Soak filter or duplicating paper for 10 min in an 8 g/l solution of nioxime (cyclohexan-l,2-dione dioxime). Remove the excess so
32、lution by blotting and hang the paper up to dry. 1 CEN EN*IS0*4524- 3 95 W 3404589 0104301 27b W BS 6670 : Part 3 : 1986 3.3 Procedure Lightly brush the electroplated coating to remove loose dust and debris, then degrease it in 1,1,l-trichloroethane vapour or other suitable solvent. Moisten a piece
33、of the nioxime paper (3.2) with water. Remove excess water by blotting. Place the treated nioxime paper on the electroplated specimen (which acts as the anode). On the other face of the nioxime paper, place a piece of the moistened blotting paper (2.2.21, followed by a high purity clean aluminium or
34、 stainless steel platen (which acts as the cathodel. Compress the assembly so that the pressure between the niox- me paper and the specimen is uniform and between 1.4 and 1,7 MPa. While under compression, pass a smooth ripple-free d.c. current from a source not exceeding 12 V. Set the current densit
35、y initially at 7,5 mA/cmz of anode area and pass for 30 s. Expose the electrogram produced on the nioxime paper to am- monia vapour and then allow to dry. The presence of any defect in the electroplated coating is revealed by a corre- sponding pink stain on the paper. When electroplated on cop- per,
36、 defects in the nickel or tin-nickel undercoat are revealed as green stains. 4 described in clause 2) Dye-transfer paper test 1 (alternative to the test 4.1 Materials During the test, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equiv
37、alent purity. Dye-transfer paper. Soak a piece of dye-transfer paper for 30 min in a freshly prepared solution containing 0,Ol mol/l of sodium chloride (NaCl) and 0,Ol mol/l of sodium carbonate Na2C03) made by dissolving O,% g of sodium chloride and 1, g sodium car- bonate together in 1 litre of wat
38、er. Remove the excess solution with blotting paper. NOTE - Dye-transfer paper may be obtained from some suppliers of photographic materials. 4.2 Procedure Remove loose dirt and debris from the electroplated coating with a soft brush and then degrease it in l,l,l-trichloroethane vapour or other suita
39、ble solvent. Place a piece of the damp dyetransfer paper (4.1) emulsion side down on the electroplated specimen (which acts as the anode), followed by a high purity clean aluminium or stainless steel platen (which acts as the cathode). Compress the assembly so that the pressure between the dye-trans
40、fer paper and the specimen is uniform and between 1,4 and 1.7 MPa. While under compression, apply a fixed potential of 4 V d.c. for 30 s. Remove the dye-transfer paper and develop it in a saturated ethanolic solution of dithiooxamide (dissolve 025 g of dithiooxamide in 100 ml of ethanol by gentle wa
41、rming; if necessary, filter when cold before use) for 30 s. Wash the electrogram produced in cold running water and allow to dry. The presence of any defect in the plated coating is revealed by a corresponding dark olive-green stain on the paper- It is essential that the test papers produced in carr
42、ying out the test be rinsed in hot water and carefully dried, on completion of the tests. NOTE - It is advisable to use tweezers for immersing the paper in the dithooxamide solution because it can produce persistent black stains on the fingers. 5 described in clause 3) Dye-transfer paper test 2 (alt
43、ernative to the test Follow the procedure described in clause 4 but use a develop- ing solution consisting of a 0.5 % rnlrn) ethanolic solution of nioxime cyclohexan-1 , it can be used also on curved surfaces, and the coloured spots do not spread from the pores to the same extent. 6.2 Reagents Durin
44、g the test, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 2 BS 6670 : Part 3 : 1986 6.2.1 Gelatine. Prepare a 10 96 (rnlrn) solution of gelatine at 60 OC with careful stirring to ensure that no air enters the solutio
45、n. Store the gelatine solution in a cold place. 6.2.2 Electrolyte solution. Prepare by mixing 20 ml of ammonia Solution (p = 0.88 g/ml) with 80 ml of water. 6.2.3 Dimethylglyoxime, indicator solution. Prepare a saturated solution of dimethylglyoxime in ethanol. test metai shall be masked before the
46、dipping. Alternatively, im- merse only the parts of the object which are coated with the test metal. Connect the sample as anode. Carry out the electrolysis for 20 s at a current density of 1 ,O mA/cm? 6.5.2 Drying When the sample has been removed from the electrolyte, leave the gelatine coating to
47、dry at room temperature for about 30 rnk alternatively, accelerated drying may be carried out for about 15 min in an air stream at room temperature. The sample shall remain in the horizontal position. 6.3 Testing solution 6.5.3 Evaluation Add, whilst stirring, 35 ml of the electrolyte solution (6.2.
48、2) and 20 ml of the indicator solution (6.2.31 to 950 g of gelatine sol- ution (6.2.1 I at 27 to 30 OC, taking care to avoid entrainment of air Pour the mixture into the electrolysis vessel and leave to cool to the working temperature, 22 to 23 OC. NOTE - Owing to variations in the quality of the ge
49、latine, no exact working temperature can be indicated. The temperature is, however, suitable for the purposes of this test if a metal sheet which has been dipped in the test solution retains, on removal from the solution, a coating 1 rnm thick. 6.4 Apparatus 6.4.1 Water-bath. fitted with a thermostat for indirect temperature control of the test solution. 6.4.2 Stirring device. 6.4.3 Inner tank, for electrolysis in the test solution. The tank shall be made of glass or acid-proof steel. The electrodes (cathodes) shall be made of platinum gauz
