1、BRITISH STANDARD BS7455-7: 1992 ISO7530-7: 1992 Analysis of nickel alloys by flame atomic absorption spectrometry Part7: Method for determination of aluminium UDC 669.245:543.422:546.62BS7455-7:1992 This British Standard, having been prepared under the directionof the Non-ferrous Metals Standards Po
2、licy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 December1992 BSI12-1999 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft for comment91/41175DC ISBN 0 580 21422 2 Committees responsible for this Briti
3、sh 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 Stee
4、l 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 Asso
5、ciation of Great Britain Steel Casting Research and Trade Association Coopted members Amendments issued since publication Amd. No. Date CommentsBS7455-7:1992 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4
6、Reagents 1 5 Apparatus 1 6 Sampling and sample preparation 1 7 Procedure 2 8 Expression of results 3 9 Test report 3 Table 1 Nominal composition of test samples 3 Table 2 Results of statistical analysis 3 List of references Inside back coverBS7455-7:1992 ii BSI 12-1999 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 ISO7530-7:1992 Nickel alloys Flame atomic absorption spectrometric analysis Part7:Determination of aluminium content, published by the International Organization for Standardizati
8、on (ISO). At present this British Standard consists of eight Parts all concerned with methods for flame spectrometric analysis of nickel alloys. Further International Standards are in preparation on the same subject and when available, these will be published as further Parts of this British Standar
9、d. A 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 Standar
10、d Corresponding 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 spect
11、rometry 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 i
12、ncorporated. This will be indicated in the amendment table on the inside front cover.BS7455-7:1992 BSI 12-1999 1 1 Scope This part of ISO7530 specifies a flame atomic absorption spectrometric method for the determination of aluminium in the range of0,2%(m/m) to4%(m/m) in nickel alloys. Typicalcompos
13、itions of nickel alloys are given inAnnexB ofISO7530-1:1990. 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 provis
14、ions 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 ap
15、plying 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. ISO
16、7530-1:1990, Nickel alloys Flame atomic absorption spectrometric analysis Part1: General requirements and sample dissolution. 3 Principle Dissolution of a test portion in acid, filtration and aspiration of the test solution into a nitrous oxide-acetylene flame of an atomic absorption spectrometer. C
17、ombustion of the filter from the acid dissolution and volatilization of silica with hydrofluoric acid. Fusion of the residue with potassium pyrosulfate, dissolution of the melt in dilute acid and aspiration of this second solution into a nitrous oxide-acetylene flame of an atomic absorption spectrom
18、eter. Measurement of the absorbance of the resonance line energy from the spectrum of aluminium and comparison with that of calibration solutions at a wavelength of309,3nm. Addition of the results found in both solutions. 4 Reagents In addition to the reagents listed in ISO7530-1, the following spec
19、ial reagents are required. 4.1 Hydrofluoric acid, 20 =1,15g/ml. WARNING 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 Potass
20、ium pyrosulfate (K 2 S 2 O 7 ), powder. 4.3 Potassium chloride (KCl), solution. Transfer48g of potassium chloride to a600ml beaker, dissolve in500ml of water and transfer to a1000ml one-mark volumetric flask. Make up to the mark with water and mix. 4.4 Aluminium, standard reference solution(1,000g/l
21、). Weigh, to the nearest0,001g,1,000g of aluminium metal of99,9% (m/m) minimum purity and transfer to a400ml beaker. Add a small drop of mercury,30ml of hydrochloric acid ( 20 =1,18g/ml) diluted1+1 and heat to complete dissolution. Filter the solution through a7cm rapid filter paper into a400ml beak
22、er. Wash the filter with100ml ofwarm water. Add85ml of hydrochloric acid ( 20 =1,18g/ml) to the filtrate, cool and transfer toa1000ml one-mark volumetric flask. Make up tothe mark with water and store in a polyethylene bottle. WARNING Mercury is highly poisonous and has an appreciable vapour pressur
23、e. It must be stored in strong, tightly closed containers. Liquid mercury must be transferred in such a manner that a spill can be contained and thoroughly cleaned up at once. CAUTION Discard the mercury in accordance with local regulations. 4.5 Aluminium, standard solution(100mg/l). Pipette100ml of
24、 the aluminium standard reference solution (4.4) into a1000ml one-mark volumetric flask and add90ml of hydrochloric acid ( 20 =1,18g/ml). Dilute to approximately800ml with water, cool, make up to the mark, mix and store in a polyethylene bottle. 5 Apparatus In addition to the apparatus specified in
25、clause5 of ISO7530-1:1990, the following items are required. 5.1 Plastics beakers, of capacity100ml or250ml, preferably made of polytetrafluoroethylene. 5.2 Platinum crucible or dish 6 Sampling and sample preparation Refer to clause6 of ISO7530-1:1990.BS7455-7:1992 2 BSI 12-1999 7 Procedure 7.1 Test
26、 portion and 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 of1 part of nitric acid ( 20 =1,41g/ml) and3 parts of hydrochloric acid ( 20 =1,18g/ml). Ap
27、ply 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. 7.1.2 Filtration and processing of filtrate Dilute the solution to50ml with w
28、ater. Filter through an11cm, low ash medium filter paper into a250ml beaker. Wash the filter with approximately50ml of hot water in10ml portions. Process the filtrate as directed in7.1.3.1 or7.1.3.2, according to the estimated aluminium level, and process the filter as directed in7.1.5. 7.1.3 Primar
29、y dilutions 7.1.3.1 Initial dilution for0,2%(m/m) to0,25%(m/m) aluminium Evaporate the filtrate from7.1.2 to a volume of approximately60ml and cool to ambient temperature. Transfer the solution to a100ml one-mark volumetric flask and add2,5ml of hydrochloric acid ( 20 =1,18g/ml) and4ml of potassium
30、chloride solution (4.3). Add4ml of nitric acid ( 20 =1,41g/ml), cool and make up to the mark with water. 7.1.3.2 Initial dilution for0,25%(m/m) to4,0%(m/m) aluminium Evaporate the filtrate from7.1.2 to a volume of approximately60ml and cool to ambient temperature. Transfer the solution to a100ml one
31、-mark volumetric flask. Add2,5ml of hydrochloric acid ( 20 =1,18g/ml) and make up to the mark with water. 7.1.4 Secondary dilutions 7.1.4.1 Secondary dilution for0,25% (m/m) to1,0%(m/m) aluminium Pipette20,0ml of the solution from7.1.3.2 into a100ml one-mark volumetric flask. Add4ml of the potassium
32、 chloride solution (4.3) and8ml of hydrochloric acid ( 20 =1,18g/ml). Dilute to80mlwith water and add4ml of nitric acid ( 20 =1,41g/ml). Cool and make up to the mark withwater. 7.1.4.2 Secondary dilution for1,0%(m/m) to2,0%(m/m) aluminium Pipette10,0ml of the solution from7.1.3.2 into a100ml one-mar
33、k volumetric flask. Add4ml of the potassium chloride solution (4.3) and9ml of hydrochloric acid ( 20 =1,18g/ml). Dilute to80mlwith water and add4ml of nitric acid ( 20 =1,41g/ml). Cool and make up to the mark withwater. 7.1.4.3 Secondary dilution for2,0% (m/m) to4,0%(m/m) aluminium Pipette5,0ml of t
34、he solution from7.1.3.2 into a100ml one-mark volumetric flask. Add4ml of thepotassium chloride solution (4.3) and9,5ml ofhydrochloric acid ( 20 =1,18g/ml). Dilute to80mlwith water and add4ml of nitric acid ( 20 =1,41g/ml). Cool and make up to the mark withwater. 7.1.5 Processing the filter 7.1.5.1 T
35、ransfer the filter from7.1.2 to a platinum crucible or dish (5.2). Dry, char and ignite to oxidize the carbon. Cool, add0,25ml of sulfuric acid ( 20 =1,83g/ml) diluted1+1 and1ml of the hydrofluoric acid (4.1). Carefully evaporate to dryness and fuse the residue with1g of potassium pyrosulfate (4.2).
36、 Allow the melt to cool and dissolve it in a small volume of water containing approximately0,25ml of hydrochloric acid ( 20 =1,18g/ml). Heat, if necessary, to complete dissolution. 7.1.5.2 Transfer the leach solution to a100ml one-mark volumetric flask and add10ml of hydrochloric acid ( 20 =1,18g/ml
37、). Dilute with more water and add4ml of nitric acid ( 20 =1,41g/ml). Cool and make up to the mark with water. Proceed as directed in7.4.1. NOTE 1A very small amount of aluminium may be present in the fused residue but it usually does not exceed0,5mg. The solution is analysed separately and the alumi
38、nium found is added to the main result. 7.2 Reagent blank solution Carry out a blank test in parallel with the determination, following the same procedure and using the same quantities of all the reagents.BS7455-7:1992 BSI 12-1999 3 7.3 Aluminium calibration solutions Using a burette, transfer to ea
39、ch of six100ml one-mark volumetric flasks,0ml,5,0ml,10,0ml,15,0ml,20,0ml and25,0ml of the aluminium standard solution(4.5). Add4ml of the potassium chloride solution (4.3) and4ml of nitric acid ( 20 =1,41g/ml). Add sufficient hydrochloric acid( 20 =1,18g/ml) to make its concentration10%(V/V), cool a
40、nd make up to themark with water. These calibration solutions correspond to0mg/l,5mg/l,10mg/l,15mg/l, 20mg/l and25mg/l of aluminium. NOTE 2It is important that all the calibration solutions contain the same concentration of hydrochloric acid. The zero solution requires an addition of10ml of hydrochl
41、oric acid ( 20 =1,18g/ml) and the last(25mg/l of aluminium), which already contains2,5ml of hydrochloric acid, requires an addition of7,5ml. 7.4 Calibration and determination 7.4.1 Atomic absorption measurements Proceed as directed in7.4.1 of ISO7530-1:1990, using a wavelength of309,3nm and a nitrou
42、s oxide-acetylene flame. 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, using the atomic absorp
43、tion measurements of the test solution (see7.1.3.1 or7.1.4) and of the solution of the fused filter residue (see7.1.5.2). Sum both percentage results for aluminium. 8.2 Precision 8.2.1 Laboratory tests Six laboratories in four countries participated in the testing of this procedure using six samples
44、 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 given in Table 2. 8.2.2.2 For sample3920 one laboratory was rejected as a Cochran outlier. For sample7013 tw
45、o laboratories were rejected, one as a Cochran and one as a Dixon outlier. However, the result which failed the Cochran test could be classified as a statistical straggler and would not have been rejected at the less critical test level given in ISO5725. 9 Test report Refer to clause9 of ISO7530-1:1
46、990. 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 3 920 3 927 7 013 7 049 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 Ba
47、l 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 Samplereference Mean % (m/m) Within-laboratory standarddeviation Between-laboratory standarddeviation Repeatability Reproducibility 825 902 3920 3927 7013 7049 0,169 0,434 0,146 0,109 1,51 0,972 0,0052 0,0045 0,0016 0,0032 0,0120 0,0
48、087 0,0114 0,0075 0,0039 0,0046 0,0046 0,0086 0,0147 0,0127 0,0047 0,0091 0,0341 0,0245 0,0354 0,0248 0,0121 0,0159 0,0365 0,03454 blankBS7455-7:1992 BSI 12-1999 List of references Seenational foreword.BS7455-7: 1992 ISO7530-7: 1992 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitu
49、tion BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this Bri
