1、BRITISH STANDARD BS EN 10318:2005 Determination of thickness and chemical composition of zinc- and aluminium-based metallic coatings Routine method The European Standard EN 10318:2005 has the status of a British Standard ICS 17.040.20; 25.220.40 BS EN 10318:2005 This British Standard was published u
2、nder the authority of the Standards Policy and Strategy Committee on 24 June 2005 BSI 24 June 2005 ISBN 0 580 46158 0 National foreword This British Standard is the official English language version of EN 10318:2005. The UK participation in its preparation was entrusted to Technical Committee ISE/18
3、, Sampling and analysis of Iron and Steel, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document ma
4、y be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users
5、are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, a
6、nd keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 23 and a back cover. The BSI copyright notice displayed in this docum
7、ent indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 10318 May 2005 ICS 17.040.20; 25.220.40 English version Determination of thickness and chemical composition of zinc- and aluminium-based met
8、allic coatings - Routine method Dtermination de lpaisseur et de la composition chimique des revtements en zinc et en alliage daluminium - Mthode de routine Bestimmung der Dicke und der chemischen Zusammensetzung metallischer berzge auf Basis von Zink und Aluminium - Standard-Verfahren This European
9、Standard was approved by CEN on 21 March 2005. CEN members are bound to comply with the CEN/CENELEC Internal 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 concerni
10、ng such national standards may be obtained on application to the Central Secretariat or to any CEN member. 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 lan
11、guage and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg,
12、Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploita
13、tion in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 10318:2005: EEN 10318:2005 (E) 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Apparatus 4 4.1 Glow discharge optical emission spectrometer .4 4.2 Data acquisition 5 5 Sampling5
14、 6 Procedure 6 6.1 Selection of spectral lines6 6.2 Optimising the glow discharge spectrometer settings 6 6.3 Calibration .8 7 Verification of the analytical accuracy 10 8 Expression of results10 8.1 Method of calculation .10 8.2 Precision11 9 Test report .17 Annex A (normative) Calculation of calib
15、ration constants and quantitative evaluation of depth profiles.18 Bibliography.23EN 10318:2005 (E) 3 Foreword This European Standard (EN 10318:2005) has been prepared by Technical Committee ECISS/TC 20 “Methods of chemical analysis of ferrous products”, the secretariat of which is held by SIS. This
16、European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2005, and conflicting national standards shall be withdrawn at the latest by November 2005. According to the CEN/CENELEC Internal Regulations, t
17、he national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pol
18、and, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 10318:2005 (E) 4 1 Scope This European Standard specifies a glow discharge optical emission spectrometric method for the determination of the thickness and chemical composition of metallic surface coatings consistin
19、g of zinc and aluminium based alloys. The alloying elements considered are aluminium, nickel, silicon and lead. This method is applicable to zinc contents between 40 % (m/m) and 100 % (m/m); aluminium contents between 0,01 % (m/m) and 60 % (m/m); nickel contents between 0,01 % (m/m) and 15 % (m/m);
20、silicon contents between 0,01 % (m/m) and 3 % (m/m); lead contents between 0,005 % (m/m) and 0,1 % (m/m). 2 Normative references Not applicable. 3 Principle The analytical method described here involves the following processes: a) Cathodic sputtering of the surface coating in a direct current glow d
21、ischarge device; b) Optical excitation of the analyte atoms in the plasma formed in the glow discharge device; c) Spectrometric measurement of characteristic emission spectral lines of the analyte atoms as a function of sputtering time (depth profile); and d) Conversion of the depth profile in units
22、 of intensity versus time to mass fraction versus depth by means of calibration functions (quantification). Calibration of the system is achieved by measurements on calibration samples of known chemical composition and measured sputtering rate. 4 Apparatus 4.1 Glow discharge optical emission spectro
23、meter 4.1.1 General An optical emission spectrometer equipped with a Grimm type (1) or similar direct current glow discharge source and a simultaneous optical spectrometer, incorporating suitable spectral lines for the analyte elements (see Table 1 for recommended lines) shall be used. The inner dia
24、meter of the hollow anode of the glow discharge shall be in the range 2 mm to 8 mm. A cooling device for thin samples, such as a metal block with circulating cooling liquid, is also recommended, but not strictly necessary for implementation of the method. It is desirable for the instrument to confor
25、m to the performance specifications given in 4.1.2 and 4.1.3, to be evaluated in 6.2.6. 4.1.2 Minimum repeatability Perform 10 measurements of the emission intensity on a homogeneous bulk sample with a content of the analyte exceeding 1 % (m/m). Allow the discharge at least 60 s stabilisation time (
26、often referred to as preburn) before each intensity measurement. Each measurement shall be located on a newly prepared surface of the sample. Calculate the standard deviation of the 10 measurements. The standard deviation should not exceed 2 % of the mean intensity of the analyte. If this is the cas
27、e, repeat the test two more times. If the high standard deviation is EN 10318:2005 (E) 5 repeatable, there is probably some malfunction in the instrument or the sample used is not homogeneous. Before proceeding, the cause of the problem should be investigated and rectified. 4.1.3 Limit of detection
28、Detection limits are instrument-dependent and matrix-dependent. Consequently, the detection limit for a given analyte cannot be uniquely determined for every available instrument or for the full range of Zn-based alloys considered here. For the purposes of this document, the detection limit for each
29、 analyte will be acceptable if it is equal to or less than one third of the lowest concentration to be determined in the intended applications. The detection limit is determined using the method explained below. a). Select a bulk sample to be used as a blank. The sample composition should be similar
30、 to the coatings to be analyzed in terms of the elemental composition of the matrix. Further, it shall be known to contain less than 0,1 mg kg -1of the analyte. b). Perform ten replicate burns on the blank. For each burn, acquire the emission intensity at the analytical wavelength for 10 s. These ar
31、e the background emission intensity measurements. The glow discharge conditions used should be the same as those that will be used in the analysis of the coated samples. For each measurement, the blank should be preburned at these conditions for a sufficient length of time to achieve stable signals
32、prior to the quantification of the emission intensity. An unsputtered area of the surface of the blank for each individual burn shall be used. c). Compute the detection limit using the following equation: m S DL = 3 where DL is the detection limit; S is the standard deviation of the ten background i
33、ntensity measurements performed in step (2); m is the analytical sensitivity derived from the instrument calibration expressed as the ratio of intensity to mass fraction. If the detection limit calculated is greater than one third of the lowest concentration to be determined in the intended applicat
34、ions, then the test should be repeated. If the second value calculated is also greater than one third of the lowest concentration to be determined in the intended applications, then there may be an instrument malfunction. In such a case, the problem should be investigated prior to analyzing unknown
35、samples. 4.2 Data acquisition Since the principle of determination is based on continuous sputtering of the surface coating, the spectrometer shall be equipped with a digital readout system for time-resolved measurement of the emission intensities. A system with capability for data acquisition speed
36、 of at least 500 measurements/second per spectral channel is recommended, but for the applications within the scope of this standard a speed of 2 measurements/second per spectral channel may be acceptable. 5 Sampling Carry out sampling in accordance with the recommendations of the manufacturer of th
37、e coated material. In general, the edges of a coated strip should be avoided. The size of the test samples should be suitable for the glow discharge source used. Typically, round or rectangular samples with a width of 20 mm to 100 mm are suitable. EN 10318:2005 (E) 6 6 Procedure 6.1 Selection of spe
38、ctral lines For each analyte to be determined there exists a number of spectral lines which can be used. Suitable lines shall be selected on the basis of several factors including the spectral range of the spectrometer used, analyte concentration range, sensitivity of the spectral lines and spectral
39、 interference from other elements present in the samples. In this type of application, where most of the analytes of interest are major elements in the samples, special attention shall be paid to the occurrence of self-absorption of certain highly sensitive spectral lines. Self- absorption may cause
40、 severe non-linearity of calibration curves at high analyte concentration levels, and such lines should therefore be avoided for the determination of majors. In Table 1, some suggestions concerning suitable spectral lines are given. Table 1 Suggested spectral lines for determination of given element
41、s Element Wavelength (nm) Estimated useful concentration range % (m/m) Comments Zn 330,26 0,001 to 100 Zn 334,50 0,001 to 100 Zn 481,053 0,001 to 100 Al 172,50 0,1 to 100 Al 396,15 0,001 to 100 a Self-absorption Ni 231,603 0,01 to 100 Ni 341,78 0,001 to 100 a Weak self-absorption Ni 349,30 0,005 to
42、100 a Weak self-absorption Pb 202,20 0,001 to 10 Pb 405,87 0,01 to 100 Si 212,41 No data available Si 251,61 No data available Si 288,16 0,001 to 20 Fe 249,318 0,01 to 100 Fe 259,94 0,01 to 100 Fe 271,44 0,1 to 100 Fe 371,94 0,005 to 100 a Weak self-absorption Fe 379,50 0,01 to 100 Cu 296,12 0,01 to
43、 100 Cu 327,40 0,001 to 5 a Strong self-absorption a Use of non-linear calibration curve recommended. 6.2 Optimising the glow discharge spectrometer settings 6.2.1 General Follow the manufacturers instructions for preparing the instrument for use. In particular, check that the entrance slit to the s
44、pectrometer is correctly adjusted, following the procedure given by the instrument manufacturer. This EN 10318:2005 (E) 7 ensures that the emission intensities are measured on the peaks of the spectral lines for optimal signal to background ratio. For further information, see e.g. ISO 14707. The sou
45、rce parameters shall be chosen to achieve three aims: adequate sputtering of the sample, to reduce the analysis time without over-heating the coatings; good crater shape, for good depth resolution; and constant excitation conditions in calibration and analysis, for optimum accuracy. There are often
46、tradeoffs among the three specified aims. Modern DC glow discharge spectrometers usually have provisions for complete control/measurement of the electrical parameters (current, voltage, power), allowing any two of these parameters to be locked to constant values by varying the pressure (active press
47、ure regulation). Older spectrometers often lack an active pressure regulation system, but the pressure can still be adjusted manually to maintain nearly constant current and voltage during calibration measurements. 6.2.2 Constant applied current and voltage The two control parameters are applied cur
48、rent and voltage. Set the power supply for the glow discharge source to constant current constant voltage operation. First set the current and voltage to typical values recommended by the manufacturer. If no recommended values are available, set the current to a value in the range 5 mA to 10 mA for
49、a 2 mm or 2,5 mm anode, 15 mA to 30 mA for a 4 mm anode, 40 mA to 100 mA for a 7 mm or 8 mm anode. If no beforehand knowledge about the optimum current is at hand, it is recommended to start with a value somewhere in the middle of the recommended range, and the voltage at 700 V. Set the high voltage of the detectors as described in 6.2.4. Adjust the discharge parameters as described in 6.2.5, adjusting first the current and if necessary the voltage. 6.2.3 Constant applied current and pressure
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