1、BRITISH STANDARDBS EN 3475-508:2007Aerospace series Cables, electrical, aircraft use Test methods Part 508: Plating thicknessThe European Standard EN 3475-508:2007 has the status of a British StandardICS 49.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g
2、50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 3475-508:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2007 BSI 2007ISBN 978 0 580 55884 9National forewordTh
3、is British Standard is the UK implementation of EN 3475-508:2007. It supersedes BS EN 3475-508:2002 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology, to Panel ACE/6/-/2, Aerospace Cables.A l
4、ist of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from leg
5、al obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 3475-508August 2007ICS 49.060 Supersedes EN 3475-508:2002 English VersionAerospace series - Cables, electrical, aircraft use - Testmethods - Part 508: Plating thicknessSrie arosp
6、atiale - Cbles lectriques usagearonautique - Mthodes dessais - Partie 508 : Epaisseurdu revtementLuft- und Raumfahrt - Elektrische Leitungen frLuftfahrtverwendung - Prfverfahren - Teil 508:Schichtdicke des UberzugsThis European Standard was approved by CEN on 21 June 2007.CEN members are bound to co
7、mply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Managem
8、ent Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theof
9、ficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slo
10、venia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN nat
11、ional Members.Ref. No. EN 3475-508:2007: E2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Test methods4 4 Requirements.9 EN 3475-508:20073 Foreword This document (EN 3475-508:2007) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-S
12、TAN). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the sta
13、tus of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2008, and conflicting national standards shall be withdrawn at the latest by February 2008. Attention is drawn to the possibility that some of the elements of this document may be the
14、subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 3475-508:2002. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to impleme
15、nt this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland an
16、d the United Kingdom. EN 3475-508:20074 1 Scope This standard specifies the procedures for measuring the plating thickness and centricity of metallic coatings on single conductors. It shall be used together with EN 3475-100. 2 Normative references The following referenced documents are indispensable
17、 for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6955, Analytical spectroscopic methods Flame emission, atomic absorption, and atomic fluorescence
18、 Vocabulary. EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General. 3 Test methods 3.1 General Five methods may be used. In the event of dispute, method 4 shall be the reference method for the measurement of plating thickness. 3.2 Test method 1 3.2.1 Principle
19、 This method uses an analytical procedure for evidence of elements and determining concentration by means of measuring the atomic absorption of optical radiation. The average plating thickness is determined by converting the measured element concentration. The determination of the centricity (distri
20、bution of the metal coating) is not possible with this method. 3.2.2 Method A flame AAS (Atome Absorption Spectrometry) is sufficient to determine metal concentrations as defined in ISO 6955. Other procedures, e.g. graphite tube, cold steam or hybrid technique, permit higher resolutions. General ins
21、tructions on the necessary equipment, such as gas fuels, oxidizers, light sources, etc., and the actual operation of the equipment can be found in the operating instructions for the relevant AAS equipment. Typical detection limits for flame AAS: see Table 1. Table 1 Element mg/l Ag 0,002 Ni 0,01 Sn
22、0,001 EN 3475-508:20075 3.2.3 Calibration In atomic absorption spectrometry calibration shall take place by the use of reference solutions (standard solutions). Standard solutions are solutions which contain the element to be assessed (e.g. Ag, Ni, Sn) in a known concentration and, if required, the
23、chemicals used in producing the sample solution and the components affecting the measurement in the same or a similar concentration to the samples for analysis. The standard calibration method involves establishing the reference function with several reference solutions starting from extinction A =
24、0 up to the extinction of the highest anticipated concentration of the solution to be measured. 3.2.4 Preparation for measurement Three samples of a single strand are dissolved in acid (e.g. nitric acid), diluted with H2O and inserted in the (AAS) measuring equipment. 3.2.5 Determining the plating t
25、hickness The average value of the plating thickness is determined by conversion of the measured concentration and the length and diameter of the sample which were determined prior to measurement. 3.3 Test method 2 3.3.1 Principle This method uses a procedure for determining the plating thickness and
26、 centricity of metallic coatings on single conductors using a scanning electron microscope (SEM). 3.3.2 Method The object to be examined is scanned with electron beams. Because of the short wavelength, this allows high resolution and magnification (up to 3 105). A further advantage is the great defi
27、nition (three-dimensional image). The geometries of the samples can be directly measured and documented. In combination with X-ray analysis equipment rapid assessment of the elements in the sample is possible. 3.3.3 Preparation for measurement a) A sample of the strand for analysis (d 0,5 mm shall b
28、e cast standing upright in epoxy resin. b) The cast samples shall be left to harden for approximately 12 h (or in accordance with the manufacturers instructions). c) The sample shall be cut at right angles to the longitudinal axis of the strand with a suitable cutting device and rubbed down with SiC
29、 (silicon carbide) paper in gradations of up to 4 000 granulations. d) The sample shall be polished with diamond paste or Al2O3with 1 m granulation. e) The sample shall be etched (e.g. with ammonium chlorocuprate) for better differentiation of the metals. f) The sample shall be gold-plated. g) The s
30、ample shall be inserted in the apparatus. The subsequent procedure may be gathered from the instructions of the equipment manufacturer. EN 3475-508:20076 3.3.4 Determining the plating thickness and the centricity of the coating The thickness of the metallic coating shall be measured in the places wh
31、ere it appears to be at its smallest and largest. The centricity ( 2 m. 3.4.3 Preparation for measurement a) A sample of the strand for analysis (d 0,5 mm shall be cast standing upright in epoxy resin. b) The cast samples shall be left to harden for approximately 12 h (or in accordance with the manu
32、facturers instructions). c) The sample shall be cut at right angles to the longitudinal axis of the strand with a suitable cutting device and rubbed down with SiC (silicon carbide) paper in gradations of up to 4 000 granulations. d) The sample shall be polished with diamond paste or Al2O3with 1 m gr
33、anulation. e) The sample shall be etched (e.g. with ammonium chlorocuprate) for better differentiation of the metals. 3.4.4 Determining the plating thickness and the centricity of the coating The thickness of the metallic coating shall be measured in the places where it appears to be at its smallest
34、 and largest. The centricity ( 1) of the coating is achieved by dividing the smallest value measured by the largest. 3.5 Test method 4 3.5.1 Principle This method uses a procedure for determining the plating thickness of metallic coatings on single strand by galvanic removal (coulometric method). As
35、sessment of centricity is not possible. EN 3475-508:20077 3.5.2 Method The use of the method assumes that the coating and base material 1) of the sample are known (nickel, silver, pure tin). In conventional measuring apparatus the reading for the amount of coating is reduced to a time reading by met
36、ering with direct current. The voltage in the element changes significantly if the coating to be measured is completely removed. This voltage impulse is amplified and acts to terminate the measurement procedure. With due regard to all physical factors, the time for the removal of the metallic coatin
37、g is a direct measurement for average plating thickness. 3.5.3 Preparation for measurement a) The surfaces of the samples (3) shall be free of grease or oxide which can prevent the flow of current and falsify the measurement. b) The test solution recommended by the equipment manufacturer shall be ch
38、osen depending on the known plating and base materials. c) The measurement procedure (galvanic removal of the plating) is completed when the metallic coating has been completely removed and the equipment has switched off. 3.5.4 Determining the plating thickness of the coating The average plating thi
39、ckness can be directly read with an accuracy of 5 % by using conventional apparatus. 3.6 Test method 5 3.6.1 Principle This method uses a procedure for determining the plating thickness of metallic coatings on single strand by chemical removal of the plating. This method is particularly suitable to
40、obtain the average of the thickness when the plating is not regular. Assessment of centricity and minimum thickness in one point are not possible. 3.6.2 Method The use of the method assumes that the coating and base material 1)of the sample are known (nickel, silver, pure tin coating on copper or al
41、uminium base material). Unlike method 4, this method does not require a timed voltage reading. Instead, it requires enough time to completely remove or deplate all of the coating material. The weight of the specimen before and after chemical removal is used along with the diameter of the plated stra
42、nd to calculate the average coating thickness. Caution should be used in selecting the solution that will remove only the coating material without affecting the base material. To improve accuracy, the specimen shall be 50 cm in length and the chemical shall be changed after each test. For large size
43、 diameter or thick coating thickness, time to completely remove or deplate all of the coating material can be increase. This increase shall be mentioned in the test report. 1) In all instances the base material is taken to be the material beneath the coating to be measured. If several different plat
44、ings are applied, various metals could appear one after the other as the base material. EN 3475-508:20078 3.6.3 Preparation for measurement a) The surfaces of the samples (3) shall be free of grease or oxide which can prevent the deplating of the coating and falsify the measurement. b) The deplating
45、 solution shall be chosen depending on the known plating and base materials (see Table 2). c) Handle samples with latex or cloth gloves. d) Clean each sample by washing with alcohol and wiping with a dry towel. e) Use measurement equipment with the following accuracies (all equipment must be calibra
46、ted. All results should be recorded to the maximum resolution of the measurement device.): 1) ruler accuracy less than or equal to 1 mm; 2) micrometer accuracy of 1,3 m or better; 3) weight scale accuracy of 0,1 mg or better. f) Cut each sample to a length of 50 cm; g) Measure the diameter at variou
47、s places along the sample and record the average diameter; h) Coil each sample so that no part of the wire touches another part; i) Weigh each sample on the scale; j) Place the solution (see Table 2 below) in a beaker capable of holding the complete sample. Use enough solution to ensure the sample i
48、s completely covered. Use fresh solution for every sample. k) Place the coil in a beaker of the solution for 15 min. Shake the solution container every 4 min. l) Rinse the sample with distilled water. 1) wipe off the sample with a dry towel. 2) allow the sample to dry in air for 15 min. m) Weigh eac
49、h sample on the scale. n) Calculate the plating results as follows: S = ()DLMM 2135,8where S is the thickness of the plating (m); M1 is the weight before test (mg); M2 is the weight after test (mg); L is the length of the sample (mm); D is the diameter of the sample before test (mm). EN 3475-508:20079 Table 2 Solution table Chemical solution Coating material Base material 50 % by volume aqueous solution of Nitric Acid Nickel Aluminum 4 Requirements The minimum plating thickness and, if required, centricity shall
