EN 14940-2:2006

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Copper and copper alloys - Determination of chromium content - Part 2: FAAS method6Cuivre et alliages de cuivre - Dosage du chrome - Partie 2 : Méthode par spectrométrie d'absorption atomique dans la flamme (SAAF)Kupfer und Kupferlegierungen - Bestimmung des Chromgehaltes - Teil 2: Flammenatomabsorptionsspektrometrisches Verfahren (FAAS)Ta slovenski standard je istoveten z:EN 14940-2:2006SIST EN 14940-2:2006en77.120.30ICS:SLOVENSKI
STANDARDSIST EN 14940-2:200601-september-2006

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14940-2June 2006ICS 77.120.30 English VersionCopper and copper alloys - Determination of chromium content -Part 2: FAAS methodCuivre et alliages de cuivre - Dosage du chrome - Partie 2 :Méthode par spectrométrie d'absorption atomique dans laflamme (SAAF)Kupfer und Kupferlegierungen - Bestimmung desCobaltgehaltes -Flammenatomabsorptionsspektrometrisches Verfahren(FAAS)This European Standard was approved by CEN on 15 May 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards 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 translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.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, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14940-2:2006: E

Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Reagents and materials.4 5 Apparatus.5 6 Sampling.5 7 Procedure.5 8 Expression of results.8 9 Precision.9 10 Test report.10 Bibliography.11

Foreword This document (EN 14940-2:2006) has been prepared by Technical Committee CEN/TC 133 “Copper and copper alloys”, the secretariat of which is held by DIN. This 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 December 2006, and conflicting national standards shall be withdrawn at the latest by December 2006. Within its programme of work, Technical Committee CEN/TC 133 requested CEN/TC 133/WG 10 "Methods of analysis" to prepare the following standard: EN 14940-2, Copper and copper alloys — Determination of chromium content — Part 2: FAAS method This is one of two parts of the standard for the determination of chromium content in copper and copper alloys. The other part is: prEN 14940-1, Copper and copper alloys — Determination of chromium content — Part 1: Titrimetric method According to the CEN/CENELEC Internal Regulations, the 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, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

1 Scope This part of this European Standard specifies a flame atomic absorption spectrometric method (FAAS) for the determination of the chromium content of copper and copper alloys in the form of unwrought, wrought and cast products. The method is applicable to products having chromium mass fractions between 0,010 % and 2,0 %. 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 referenced document (including any amendments) applies. ISO 1811-1, Copper and copper alloys — Selection and preparation of samples for chemical analysis — Part 1: Sampling of cast unwrought products ISO 1811-2, Copper and copper alloys — Selection and preparation of samples for chemical analysis — Part 2: Sampling of wrought products and castings NOTE Informative references to documents used in the preparation of this standard, and cited at the appropriate places in the text, are listed in the Bibliography. 3 Principle Dissolution of a test portion in nitric acid and digestion in sulphuric acid followed, after suitable dilution, by aspira-tion into an air-acetylene or into a nitrous oxide-acetylene flame of an atomic absorption spectrometer. Measure-ment of the absorption of the 357,9 nm line emitted by a chromium hollow-cathode lamp. 4 Reagents and materials 4.1 General During the analysis use only reagents of recognised analytical grade and only distilled water or water of equivalent purity. 4.2 Sulphuric acid, H2SO4 (ρ = 1,84 g/ml). 4.3 Hydrogen peroxide, H2O2 30 % (mass fraction) solution. 4.4 Nitric acid, HNO3 (ρ = 1,40 g/ml). 4.5 Nitric acid solution, 1 + 1 Dilute 500 ml of nitric acid (4.4) in 500 ml of water. 4.6 Hydrofluoric acid, HF (ρ = 1,13 g/ml). WARNING — Hydrofluoric acid is a hazardous substance. Care shall be taken and it shall be used under an efficient fume hood.

4.7 Chromium stock solution, 0,500 g/l Cr Weigh 1,414 2 g of potassium dichromate (K2Cr2O7 > 99,9 %), previously dried at 140 °C and allowed to cool in a desiccator. Place in a 400 ml beaker and dissolve in about 20 ml of water. Add 5 ml of sulphuric acid (4.2) and, while cooling, cautiously add the hydrogen peroxide solution (4.3), adding an excess of about 2 ml after efferves-cence has ceased. Allow the solution to stand at ambient temperature until the yellow colour has completely disappeared (several hours), then transfer the solution quantitatively into a 1 000 ml one-mark volumetric flask. Dilute to the mark with water and mix well.
Prepare this solution immediately prior to use. 1 ml of this solution contains 0,500 mg of Cr.
4.8 Chromium standard solution, 0,025 g/l Cr Transfer 25,0 ml of the chromium stock solution (4.7) into a 500 ml one-mark volumetric flask. Dilute to the mark with water and mix well. Prepare this solution immediately prior to use. 1 ml of this solution contain 0,025 mg of Cr. 4.9 Copper base solution, 20 g/l Cu Weigh 20,0 g of chromium-free copper (Cu ≥ 99,90 %, Cr ≤ 0,001 %) and transfer into a 1 000 ml beaker. Add, in small portions, 400 ml of nitric acid solution (4.5). Cover the beaker. If necessary, heat gently to help dissolution. After cooling, add cautiously 200 ml of the sulphuric acid (4.2); heat to the evolution of copious white fumes and continue for 5 min. Cool and add cautiously about 200 ml of water and heat to complete the dissolution. Cool to room temperature, transfer the solution quantitatively into a 1 000 ml one-mark volumetric flask, dilute to the mark with water and mix well. 5 Apparatus 5.1 Ordinary laboratory apparatus. 5.2 Atomic absorption spectrometer, fitted with an air-acetylene or a nitrous-oxide acetylene burner. 5.3 Chromium hollow-cathode lamp. 6 Sampling Sampling shall be carried out in accordance with ISO 1811-1 or ISO 1811-2, as appropriate. Test samples shall be in the form of fine drillings, chips or mil
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