1、 Reference number ISO 17925:2004(E) ISO 2004INTERNATIONAL STANDARD ISO 17925 First edition 2004-11-01 Zinc and/or aluminium based coatings on steel Determination of coating mass per unit area and chemical composition Gravimetry, inductively coupled plasma atomic emission spectrometry and flame atomi
2、c absorption spectrometry Revtements base de zinc et/ou daluminium sur acier Dtermination de la masse surfacique et de la composition chimique du revtement Gravimtrie, spectromtrie dmission atomique avec plasma induit par haute frquence et spectromtrie dabsorption atomique dans la flamme ISO 17925:2
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6、 ISO 2004 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in
7、the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2004 All rights reservedISO 17925:2004(E) ISO 2004 All rights reserved iiiContents Page Foreword i
8、v 1 Scope 1 2 Normative references . 1 3 Principle . 2 4 Reagents 2 5 Apparatus. 5 5.1 General. 5 5.2 Inductively coupled plasma atomic emission spectrometer (ICP-AES) 5 5.3 Flame atomic absorption spectrometer (FAAS) 6 5.4 Platinum crucible 7 6 Sampling and samples . 7 7 Determination procedure . 7
9、 7.1 Sample preparation. 7 7.2 Determination procedure for mass per unit area 7 7.3 Procedure of determination of chemical composition by inductively coupled plasma atomic emission spectrometric method. 8 7.4 Procedure of determination of chemical composition by flame atomic absorption method zinc,
10、aluminium, nickel and iron contents. 14 8 Expression of results 14 8.1 Expression of result in mass per unit area 14 8.2 Expression of result of chemical compositions 15 9 Test report 17 Annex A (informative) Analyte content 18 Annex B (informative) Additional information on the international cooper
11、ative tests 19 Annex C (informative) Graphical representation of precision data. 22 ISO 17925:2004(E) iv ISO 2004 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Int
12、ernational Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison w
13、ith ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of techni
14、cal committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn
15、to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17925 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of determination of chemical
16、composition. INTERNATIONAL STANDARD ISO 17925:2004(E) ISO 2004 All rights reserved 1Zinc and/or aluminium based coatings on steel Determination of coating mass per unit area and chemical composition Gravimetry, inductively coupled plasma atomic emission spectrometry and flame atomic absorption spect
17、rometry 1 Scope This International Standard specifies methods of determining the coating mass per unit area by gravimetry and chemical composition on one side-surface of zinc- and/or aluminium-based coatings on steel by means of inductively coupled plasma atomic emission spectrometric or flame atomi
18、c absorption spectrometry. For example, this test method applies for zinc and/or aluminium based coatings on steel such as galvanize (hot dip and electrolytic), galvaneal (hot-dip), zinc-nickel electrolytic, zinc-5 % aluminium coating (hot-dip) and zinc- 55 % aluminium coating (hot-dip). Galvanizing
19、 gives a pure zinc coating. Galvanealling gives a zinc-iron alloyed coating. Zinc-nickel electrolytic methods give zinc-nickel alloyed coatings. This method is applicable to zinc contents between 40 % (mass fraction) and 100 % (mass fraction); aluminium contents between 0,02 % (mass fraction) and 60
20、 % (mass fraction); nickel contents between 7 % (mass fraction) and 20 % (mass fraction); iron contents between 0,2 % (mass fraction) and 20 % (mass fraction); silicon contents between 0,2 % (mass fraction) and 10 % (mass fraction); lead contents between 0,005 % (mass fraction) and 2 % (mass fractio
21、n). For example, the applicable elements for these products are as follows: galvanizing is specified for iron and aluminium; galvanealling is specified for zinc, iron and aluminium; zinc-nickel electrolytic methods are specified for zinc, iron and nickel; zinc-5 % aluminium coating is specified for
22、zinc, iron, aluminium and silicon; zinc-55 % aluminium is specified for zinc, iron, aluminium and silicon. FAAS determination for the chemical composition of a coating layer is not applicable for zinc. These test methods are intended as referee methods to test such materials for compliance with mass
23、 per unit area and compositional specifications of International Standards. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the refere
24、nced document (including any amendments) applies. ISO 648:1977, Laboratory glassware One-mark pipettes ISO 1042:1998, Laboratory glassware One-mark volumetric flasks ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 5725-1:1994, Accuracy (trueness and precision) o
25、f measurement methods and results Part 1: General principles and definitions ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 17925:2004(E) 2 ISO
26、2004 All rights reservedISO 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results Part 3: Intermediate measures of the precision of a standard measurement method ISO 14284:1996, Steel and iron Sampling and preparation of samples for the determination of chemical compositi
27、on 3 Principle Stripping the coating on one side on the base steel in a mixture of hydrochloric acid solution containing an inhibitor to prevent the attack on the base steel. Determination of the mass per unit area of coating from the mass difference of the specimen before and after stripping. Calcu
28、lating the coating mass as the mass difference divided by the specimens surface area. Dilution of the stripped solution of the coating on one side. Filtration and nebulization of the solution into an inductively coupled plasma atomic emission spectrometer (ICP-AES) or flame atomic absorption spectro
29、meter (FAAS). Calculating the chemical compositions of coating layer as the content of the analytical element divided by the pre-measured coating mass. Examples of the analytical lines are given in Table 1. Table 1 Examples of analytical lines together with interfering elements ICP-AES FAAS Element
30、Analytical line nm Interfering elements Analytical line nm Interfering elements Zinc 481,0 206,19 Aluminium 396,15 309,3 306,16 Nickel 231,60 232,00 231,10 233,75 Iron 271,44 259,94 248,33 252,29 Silicon 251,61 288,16 Aluminium 251,61 288,16 Aluminium Lead 220,35 Zinc Aluminium 217,00 283,31 4 Reage
31、nts During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only grade 2 water as specified in ISO 3696. 4.1 Hydrochloric acid, HCl, 1,18 g/ml. 4.2 Hydrochloric acid, HCl, diluted 1+10. 4.3 Nitric acid, HNO 3 , 1,40 g/lml. ISO 17925:2004(E) ISO 2004 All rig
32、hts reserved 34.4 Nitric acid, HNO 3 , diluted 1+1. 4.5 Mixed acid, prepared by adding 50 ml of nitric acid (4.3) and 10 ml of hydrochloric acid (4.1) to a flask containing 150 ml of water and mixing. 4.6 Sodium carbonate, Na 2 CO 3 . 4.7 Hexamethylenetetramine, C 6 H 12 N 4 , capable of preventing
33、acid attack of the base metal while stripping the coating from the base steel. 4.8 Stripping solution, prepared by transferring from 170 ml to 500 ml of hydrochloric acid (4.1) to a 1 l graduated cylinder containing from 450 ml to 820 ml of water and adding 3,5 g of hexamethylenetetramine (4.7) then
34、 diluting to the mark with water followed by mixing. NOTE For an electrolytic zinc coated steel such as one with a lower coating mass, it would be better to use diluted hydrochloric acid for stripping in order to prevent the dissolution of base steel. 4.9 Stop-off materials, capable of protecting on
35、e side of a coated piece of steel sheet while the other side is being stripped in hydrochloric acid solution, without contaminating the acid solution and either gaining or losing mass thus avoiding interference with coating mass and chemical composition determination. NOTE 1 Acid-resistant paints, l
36、acquers or acid-resistant tapes are commonly used as stop-off materials. NOTE 2 For this purpose mechanical devices may also be used, fastened to the test specimen instead of the above materials. 4.10 Zinc stock standard solution, 1 000 mg/l, prepared as follows: weigh, to the nearest 0,000 5 g, 0,5
37、 g of high purity zinc (minimum 99,99 % by mass) and dissolve in 25 ml hydrochloric acid (4.1). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with wa
38、ter and mix. 4.11 Zinc standard solution A, 100 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the zinc stock standard solution (4.10) into a calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix. 4.12 Zi
39、nc standard solution B, 10 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the zinc standard solution A (4.11) into a calibrated 1 000 ml one- mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix. 4.13 Zinc standard solution for
40、 matrix matching, 10 000 mg/l, prepared as follows: weigh, to the nearest 0,01 g, 10 g of high purity zinc (minimum 99,99 % by mass) and dissolve in 200 ml hydrochloric acid (4.1), Cool and transfer the solution quantitatively to a calibrated 1 000 ml one-mark volumetric flask. Keep the flask at the
41、 same temperature as that at which the flask was calibrated. Dilute to the mark with water and mix. 4.14 Aluminium stock standard solution, 1 000 mg/l, prepared as follows: weigh, to the nearest 0,000 5 g, 0,5 g of high purity aluminium (minimum 99,95 % by mass) and dissolve in a mixture of 25 ml hy
42、drochloric acid (4.1) and 5 ml nitric acid (4.3). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with water and mix. ISO 17925:2004(E) 4 ISO 2004 All
43、rights reserved4.15 Aluminium standard solution A, 100 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the aluminium stock standard solution (4.14) into a calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and
44、mix. 4.16 Aluminium standard solution B, 10 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the aluminium standard solution A (4.15) into a calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix. 4.17 Alumi
45、nium standard solution for matrix matching, 10 000 mg/l, prepared as follows: weigh, to the nearest 0,01 g, 10 g of high purity aluminium (minimum 99,99 % by mass) and dissolve in a mixture of 200 ml hydrochloric acid (4.1) and 5 ml nitric acid (4.3). Cool and transfer the solution quantitatively to
46、 a calibrated 1 000 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with water and mix. 4.18 Nickel stock standard solution, 1 000 mg/l, prepared as follows: weigh, to the nearest 0,000 5 g, 0,5 g of high purity nicke
47、l (minimum 99,95 % by mass) and dissolve in 30 ml nitric acid (1+1) (4.4). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with water and mix. 4.19 Nic
48、kel standard solution A, 100 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the nickel stock standard solution (4.18) into a calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix. 4.20 Nickel standard sol
49、ution B, 10 mg/l, prepared as follows: using a calibrated pipette, transfer 100 ml of the nickel standard solution A (4.19) into a calibrated 1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix. 4.21 Iron stock standard solution, 1 000 mg/l, prepared as follows: weigh, to the nearest 0,000 5 g, 0,5 g of high purity iron (minimum 99,95 % by mass) and dissolve in 25 ml hydrochloric acid (4.1). Cool and transfer the solution quantitatively to a calib
