1、ASD STANDARD NORME ASD ASD NORM prEN 3475-508 Edition P 2 September 2006 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Gulledelle 94 - B-1200 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 763 3565 - www.asd-stan.orgICS: 49.060 Supersedes edition P 1 of Jun
2、e 1997 and will supersede EN 3475-508:2002 Descriptors: ENGLISH VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 508: Plating thickness Srie arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 508 : paisseur du revtement Luft- und Raumfahrt Elektrische Le
3、itungen fr Luftfahrtverwendung Prfverfahren Teil 508: Schichtdicke des Uberzugs This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the needs of the European Aer
4、ospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-i
5、dentification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national members
6、have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. Edition approved for publication 30 September 2006 Comments should be sent within six months after the date of publication to ASD-STAN
7、 Electrical Domain Copyright 2006 by ASD-STAN prEN 3475-508:20062 Contents Page Foreword2 1 Scope 3 2 Normative references 3 3 Test methods3 3.1 General3 3.2 Test method 1.3 3.2.1 Principle3 3.2.2 Method 3 3.2.3 Calibration 4 3.2.4 Preparation for measurement.4 3.2.5 Determining the plating thicknes
8、s.4 3.3 Test method 2.4 3.3.1 Principle4 3.3.2 Method 4 3.3.3 Preparation for measurement.4 3.3.4 Determining the plating thickness and the centricity of the coating .5 3.4 Test method 3.5 3.4.1 Principle5 3.4.2 Method 5 3.4.3 Preparation for measurement.5 3.4.4 Determining the plating thickness and
9、 the centricity of the coating .5 3.5 Test method 4.5 3.5.1 Principle5 3.5.2 Method 6 3.5.3 Preparation for measurement.6 3.5.4 Determining the plating thickness of the coating 6 3.6 Test method 5.6 3.6.1 Principle6 3.6.2 Method 6 3.6.3 Preparation for measurement.7 4 Requirements.8 Foreword This st
10、andard was reviewed by the Domain Technical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 3475-508:20063 1 Scope This st
11、andard 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 for the application of this document. For dated refere
12、nces, 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 Vocabulary. EN 3475-100, Aerospace series Cables, elec
13、trical, 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 This method uses an analytical procedure for evidence
14、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 (distribution of the metal coating) is not possible with this
15、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 instructions on the necessary equipment, such as gas fuels
16、, 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 0,001 prEN 3475-508:20064 3.2.3 Calibration In atomic a
17、bsorption 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 chemicals used in producing the sample solution and t
18、he 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 = 0 up to the extinction of the highest anticipated con
19、centration 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 thickness The average value of the plating thickness i
20、s 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 centricity of metallic coatings on single conductors
21、 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 definition (three-dimensional image). The geometries of t
22、he 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 be cast standing upright in epoxy resin. b) The cast s
23、amples 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 (silicon carbide) paper in gradations of up to 4 000
24、 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 sample shall be inserted in the apparatus. The subsequ
25、ent procedure may be gathered from the instructions of the equipment manufacturer. prEN 3475-508:2006 5 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 where it appears to be at its smallest and largest.
26、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 manufacturers instructions). c) The sample shall be cu
27、t 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 granulation. e) The sample shall be etched (e.g. wit
28、h 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 and largest. The centricity ( 1) of the coating i
29、s 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). Assessment of centricity is not possible. prEN 3475-
30、508:20066 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 metering with direct current. The voltage in the el
31、ement 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 coating is a direct measurement for average plating th
32、ickness. 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 chosen depending on the known plating and base mat
33、erials. 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 thickness can be directly read with an accuracy of
34、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 obtain the average of the thickness when the pla
35、ting 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 aluminium base material). Unlike method 4, this me
36、thod 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 strand to calculate the average coating thickness. C
37、aution should be used in selecting the solution that will remove only the coating material without affecting the base material. 1) In all instances the base material is taken to be the material beneath the coating to be measured. If several different platings are applied, various metals could appear
38、 one after the other as the base material. prEN 3475-508:20067 To improve accuracy, the specimen shall be 50 cm in length and the chemical shall be changed after each test. For large size diameter or thick coating thickness, time to completely remove or deplate all of the coating material can be inc
39、rease. This increase shall be mentioned in the test report. 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 solution shall be chosen depending on the kno
40、wn 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 calibrated. All results should be recorded to the max
41、imum 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 various places along the sample and record the avera
42、ge 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 is completely covered. Use fresh solution for e
43、very 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 each sample on the scale. n) Calculate the platin
44、g 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). prEN 3475-508:20068 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 be stated in the technical specifications or product standards.
