BS 7455-8-1992 Analysis of nickel alloys by flame atomic absorption spectrometry - Method for determination of silicon《采用火焰原子吸收光谱法对镍合金的分析 第8部分 硅的测定方法》.pdf

1、BRITISH STANDARD BS7455-8: 1992 ISO7530-8: 1992 Analysis of nickel alloys by flame atomic absorption spectrometry Part8: Method for determination of silicon UDC 669.245:543.422:546.28BS7455-8:1992 This British Standard, having been prepared under the directionof the Non-ferrous Metals Standards Poli

2、cy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 December1992 BSI11-1999 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft for comment91/41174 DC ISBN 0 580 21423 0 Committees responsible for this Britis

3、h Standard The preparation of this British Standard was entrusted by the Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee NFM/10, upon which the following bodies were represented: Association of Bronze and Brass Founders British Non-ferrous Metals Federation British Steel

4、 Industry Department of Trade and Industry (Laboratory of the Government Chemist) Engineering Equipment and Materials Users Association Institute of British Foundrymen London Metal Exchange Ministry of Defence Nickel Development Institute Non-ferrous Metal Stockists Stainless Steel Fabricators Assoc

5、iation of Great Britain Steel Casting Research and Trade Association Coopted members Amendments issued since publication Amd. No. Date CommentsBS7455-8:1992 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 R

6、eagents 1 5 Apparatus 1 6 Sampling and sample preparation 1 7 Procedure 2 8 Expression of results 2 9 Test report 2 Table 1 Nominal composition of test samples 3 Table 2 Results of statistical analysis 3 List of references Inside back coverBS7455-8:1992 ii BSI 11-1999 National foreword This Part of

7、BS7455 has been prepared under the direction of the Non-ferrous Metals Standards Policy Committee. It is identical with ISO7530-8:1992 Nickel alloys Flame atomic absorption spectrometric analysis Part8:Determination of silicon content, published by the International Organization for Standardization

8、(ISO). At present this British Standard consists of eight Parts all concerned with methods for flame spectrometric analysis of nickel alloys. Further InternationalStandards are in preparation on the same subject and when available, these will be published as further Parts of this British Standard. A

9、 British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Co

10、rresponding British Standard ISO5725:1986 BS5497 Precision of test methods Part1:1987 Guide for the determination of repeatability and reproducibility for a standard test method by inter-laboratory tests (Identical) ISO7530-1:1990 BS7455 Analysis of nickel alloys by flame atomic absorption spectrome

11、try Part1:1991 General requirements and sample dissolution (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incor

12、porated. This will be indicated in the amendment table on the inside front cover.BS7455-8:1992 BSI 11-1999 1 1 Scope This part of ISO7530 specifies a flame atomic absorption spectrometric method for the determination of silicon in the range of0,2%(m/m) to1%(m/m) in nickel alloys. Typical composition

13、s of nickel alloys are given in Annex B of ISO7530-1:1990. The general requirements concerning the apparatus, sampling, dissolution of the test sample, atomic absorption measurements, calculations and test report are given in ISO7530-1. 2 Normative references The following standards contain provisio

14、ns which, through reference in this text, constitute provisions of this part of ISO7530. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO7530 are encouraged to investigate the possibility of appl

15、ying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. ISO75

16、30-1:1990, Nickel alloys Flame atomic absorption spectrometric analysis Part1: General requirements and sample dissolution. 3 Principle Dissolution of a test portion in acid and aspiration of the test solution into a nitrous oxide-acetylene flame of an atomic absorption spectrometer. Measurement of

17、the absorbance of the resonance line energy from the spectrum of silicon and comparison with that of calibration solutions at a wavelength of251,6nm. 4 Reagents In addition to the reagents listed in ISO7530-1, the following special reagents are required. 4.1 Hydrofluoric acid, 20 =1,15g/ml. WARNING

18、Hydrofluoric acid is extremely irritating and corrosive to skin and mucous membranes, producing severe skin burns which are slow to heal. In the case of contact with skin, wash well with water and seek medical advice. 4.2 Hydrofluoric acid, 20 =1,15g/ml, diluted1+9. 4.3 Lithium chloride (LiCl), solu

19、tion. Transfer25g of lithium chloride to a250ml beaker and dissolve in150ml of warm water. Cool, transfer to a200ml one-mark volumetric flask and make up to the mark with water. Store in a plastics bottle. 4.4 Silicon, standard reference solution(1,000g/l). Weigh, to the nearest0,001g,1,000g of elem

20、ental silicon powder of99,9%(m/m) minimum purity and transfer to a250ml polytetrafluoroethylene beaker. Add20ml of nitric acid( 20 =1,41g/ml) and wash the beaker walls with water. Add hydrofluoric acid(4.1) drop by drop to initiate and sustain the reaction (approximately10ml of hydrofluoric acid are

21、 required). After most of the silicon has dissolved, add10ml more hydrofluoric acid, cover the beaker and keep at less than50 C until dissolution is complete. Transfer to a1000ml plastics one-mark volumetric flask, add20ml of hydrochloric acid( 20 =1,18g/ml) and make up to the mark with water. Store

22、 in a polyethylene bottle. 4.5 Silicon, standard solution(100mg/l). Transfer, using a plastics pipette,50,0ml of the silicon standard reference solution(4.4) into a500ml plastics one-mark volumetric flask. Add5ml of the dilute hydrofluoric acid(4.2) and10ml of hydrochloric acid( 20 =1,18g/ml). Dilut

23、e to the mark with water, mix and store in a polyethylene bottle. 5 Apparatus IMPORTANT Plastics beakers and volumetric ware shall be used throughout the procedure. In addition to the apparatus specified in clause5 of ISO7530-1:1990, the following plastics laboratory items are required. 5.1 Plastics

24、 beakers, of capacity250ml, preferably of polytetrafluoroethylene. 5.2 Acrylic body burette,50ml graduated in0,1ml divisions. 5.3 Polypropylene pipettes,10ml,25ml and50ml. 5.4 Polypropylene or polymethylpentene one-mark volumetric flasks, of capacity100ml,500ml or1000ml. 6 Sampling and sample prepar

25、ation Refer to clause6 of ISO7530-1:1990.BS7455-8:1992 2 BSI 11-1999 7 Procedure 7.1 Preparation of test solution 7.1.1 Dissolution of a test portion in acid Weigh, to the nearest0,001g,1,00g of the test sample and transfer it to a clean plastics beaker(5.1). Add20ml of a mixture of one part of nitr

26、ic acid( 20 =1,41g/ml) and three parts of hydrochloric acid( 20 =1,18g/ml). Apply sufficient heat to initiate and maintain the reaction until dissolution is complete. If the alloy resists dissolution, add hydrochloric acid( 20 =1,18g/ml) in1ml increments and continue heating to dissolve the sample.

27、7.1.2 Preparation of the final test solution Cool the solution and wash the cover and beaker walls with a minimum of water. Add5ml of the dilute hydrofluoric acid(4.2) and allow to stand for1h, swirling intermittently. 7.1.3 Primary dilutions 7.1.3.1 Initial dilution for0,2%(m/m) to0,25%(m/m) silico

28、n Transfer the test solution from7.1.2 to a100ml plastics one-mark volumetric flask, add2ml of hydrochloric acid( 20 =1,18g/ml) and dilute to approximately80ml with water. Add3ml of the lithium chloride solution(4.3) and make up to the mark with water. 7.1.3.2 Initial dilution for0,5%(m/m) to1,0%(m/

29、m) silicon Transfer the test solution from7.1.2 to a100ml plastics one-mark volumetric flask and make up to the mark with water. 7.1.4 Secondary dilution for0,5%(m/m) to1,0%(m/m) silicon Pipette50,0ml of the solution from7.1.3.2 into a100ml plastics one-mark volumetric flask. Add2ml of hydrochloric

30、acid( 20 =1,18g/ml) and2,5ml of the dilute hydrofluoric acid(4.2). Dilute to approximately80ml with water and mix. Add3ml of the lithium chloride solution(4.3) and make up to the mark with water. 7.2 Reagent blank solution Carry out a blank test in parallel with the determination, following the same

31、 procedure and using the same quantities of all the reagents. 7.3 Silicon calibration solutions Using the plastics burette(5.2), transfer to each of six100ml plastics one-mark volumetric flasks,0ml,10,0ml,20,0ml,30,0ml,40,0ml and50,0ml of the silicon standard solution(4.5). Add2ml of hydrochloric ac

32、id( 20 =1,18g/ml) and5ml of the dilute hydrofluoric acid(4.2). Dilute to approximately80ml with water and mix. Add3ml of the lithium chloride solution(4.3) and make up to the mark with water. These calibration solutions correspond to0mg/l10mg/l, 20mg/l,30mg/l,40mg/l and50mg/l of silicon. 7.4 Calibra

33、tion and determination 7.4.1 Atomic absorption measurements Proceed as directed in7.4.1 of ISO7530-1:1990, using a wavelength of251,6nm and a nitrous oxideacetylene flame. NOTE 1To eliminate silica memory effects, the burner system must be preconditioned before analysis by aspirating a dilute soluti

34、on of hydrofluoric acid10ml of dilute hydrofluoric acid(4.2) and90ml of water. With the flame burning, aspirate this dilute acid solution until the original baseline signal is restored, i.e.when the silica deposit on the burner top has been volatilized. Then proceed with the aspiration of distilled

35、water as directed. 7.4.2 Preparation of calibration curves Proceed as directed in7.4.2 of ISO7530-1:1990. 7.5 Number of determinations Carry out the determination at least in duplicate. 8 Expression of results 8.1 Calculation Proceed as directed in8.1 of ISO7530-1:1990. 8.2 Precision 8.2.1 Laborator

36、y tests Six laboratories in four countries participated in the testing of this procedure using six samples of nominal composition given in Table 1. 8.2.2 Statistical analysis 8.2.2.1 Results were treated according to ISO5725 as described in8.2.2 of ISO7530-1:1990. The results of this analysis are gi

37、ven in Table 2. 8.2.2.2 No outliers were identified by statistical tests. 9 Test report Refer to clause9 of ISO7530-1:1990. BS7455-8:1992 BSI 11-1999 3 Table 1 Nominal composition of test samples%(m/m) Table 2 Results of statistical analysis Sample Al Co Cr Cu Fe Mn Ni Si Ti 825 902 3920 3927 7013 7

38、049 0,2 0,4 0,15 0,1 1,5 1 0,07 0,05 2 1 17 0,01 21 5 19 20 20 15 1,6 0,04 0,1 0,05 0,2 0,15 30 48 3 44 0,2 7 0,7 0,4 0,3 0,4 0,05 0,8 Bal Bal Bal Bal Bal Bal 0,4 0,35 0,6 0,8 0,7 0,3 1,1 2,5 2,3 0,6 2,4 2,3 Sample reference Mean % (m/m) Within-laboratory standard deviation Between-laboratory standa

39、rd deviation Repeatability Reproducibility 825 902 3920 3927 7013 7049 0,403 0,344 0,614 0,816 0,721 0,336 0,0066 0,0039 0,016 6 0,019 5 0.017 4 0,0066 0,0236 0,014 9 0,0175 0,0403 0,0213 0,014 4 0,0185 0.0110 0,047 0 0,055 1 0,049 1 0,018 7 0,0694 0,043 5 0,0682 0,127 0,077 8 0.044 84 blankBS7455-8

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