7627/6 (TSO International Standard INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAR OPIAHM3AUMA NO CTAHAAPTM3AUWWORGANISATION INTE RNATIONALE DE NORMALISATION Hardmetals Chemical analysis by flame atomic absorption spectrometry Part 6 : Determination of chromium in contents from 0,01 to 2 % (m/m) Métaux-durs - Analyse chimique par spectrométrie d'absorption atomique dans la flamme - Partie 6 : Dosage du chrome a des teneurs comprises entre 0,01 et 2 % (m/m) First edition - 1985-04-01 ISO 7627/6-1985 (E) UDC 669.018.25 : 543.422 : 546.76 Ref. No. ISO 7627/6-1985 (E) Descriptors : powder metallurgy, hard metals, chemical analysis, determination of content, chromium, atomic absorption method. Price based on 2 pages Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (IsO member bodies). The work of preparing International Standards is normally carried out through 1so 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, govern- mentat and non-governmental, in liaison with ISo, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International StandardISO 7627/6 was prepared by Technical Committee ISO/TC 119, Powder metallurgy. ? International Organization for Standardization, 1985 Printed in Switzerland Copyright International Organization for Standardization ISO 7627/6-1985 (E) INTERNATIONAL STANDARD Hardmetals --- Chemical analysis by flame atomic absorption spectrometry Part 6 : Determination of chromium in contents from 0,01 to 2 % (m/m) Scope and field of application 3.4 Hydrogen peroxide, 30 % (m/ m). This part of 1so 7627 specifies the method to be used for the 3.5 High purity stock solution, for calibration purposes, determination of the chromium content of hardmetals within containing 1,000 g of chromium per litre. the range 0,01 to 2 % (m/ m) by flame atomic absorption spec- trometry. NOTE- This value is understood to establish a maximum limit of 1,000 5 g and a minimum limit of 0,999 5 g. General requirements concerning the field of application, prin- ciple, interfering elements, apparatus, sampling and test report are given in iSO 7627/1. 4 Procedure 4.1 Test portion 2 Reference Weigh, to the nearest 0,001 g, the relevant amount of the test ISO7627/1,Hardmetals-Chemicalanalysisbyflameatomic sample indicated in table 1. Transfer it to a 100 ml conical flask absorption spectrometry - Part 1 : General requirements. (preferably of quartz). Reagents NOTE - In this special case, the sample shall pass a 0,18 mm sieve. 4.2 Dissolution of the test portion 3.1 Potassium pyrosulfate. Add 5 g of the potassium pyrosulphate (3.1) and a few drops of 3.2Perchloric acid, Q 1,54 or 1,67 g/ml. the perchloric acid (3.2) to the beaker containing the test por- tion (4.1) and heat gently until the test portion is completely 3.3 Ammonium citrate, solution. dissolved. Add 40 mi of the ammonium citrate solution (3.3), and about 0,5 ml of the hydrogen peroxide (3.4). Then transfer Dissolve 100 g of citric acid in 1 500 ml of water and add 400 ml the solution to a 100 ml polypropylene one-mark volumetric of ammonia solution (o 0,91 g/ml). flask and dilute to the mark. Table 1 -- Test portion, instrumental parameters and characteristics of calibration functions Dilution Reciprocal volume (V) sensitivity, Oxidant Wavelength Linear range1) Content Test portion for the test for 1 % portion1) absorption1) % nm μg/ml % g ml 0,01 to 0,1 0,500 N20 357,9 0,11 to 0,12 100 0 500 N20 357,9 0,11 0,1 to 0,5 0,1 to 0,5 0,500 N20 357,9 0,11 0,1 to 0,5