EN 15979:2011

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Y]EXMDQMHPPrüfung keramischer Roh- und Werkstoffe - Direkte Bestimmung der Massenanteile an Verunreinigungen in pulver- und kornförmigem Siliciumcarbid mittels OES und Anregung im GleichstrombogenEssais des matières premières et matériaux de base céramiques - Détermination directe des fractions massiques d'impuretés dans les poudres et granulés de carbure de silicium par OES à excitation d'arc DCTesting of ceramic raw and basic materials - Direct determination of mass fractions of impurities in powders and granules of silicon carbide by OES by DC arc excitation81.060.10SurovineRaw materialsICS:Ta slovenski standard je istoveten z:EN 15979:2011SIST EN 15979:2011en,fr,de01-november-2011SIST EN 15979:2011SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15979
January 2011 ICS 81.060.10 English Version
Testing of ceramic raw and basic materials - Direct determination of mass fractions of impurities in powders and granules of silicon carbide by OES by DC arc excitation
Essai des matières premières et matériaux de base céramiques - Détermination directe des
fractions massiques d'impuretés dans les poudres et granulés de carbure de silicium par OES à l'excitation d'arc DC
Prüfung keramischer Roh- und Werkstoffe - Direkte Bestimmung der Massenanteile an Verunreinigungen in pulver- und kornförmigem Siliciumcarbid mittels OES und Anregung im Gleichstrombogen This European Standard was approved by CEN on 10 December 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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.
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B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15979:2011: ESIST EN 15979:2011

Results of inter-laboratory study. 10Annex B (informative)
Wavelength and working range . 14Annex C (informative)
Possible interferences and their elimination . 16Annex D (informative)
Information regarding the evaluation of the uncertainty of the mean value . 19Annex E (informative)
Commercial certified reference materials . 20Bibliography . 21 SIST EN 15979:2011

NOTE There are positive interferences for materials such as e.g. graphite, B4C, BN, WC and several refractory metal oxides. This testing procedure is applicable to mass fractions of the impurities mentioned above from approximately
1 mg/kg up to approximately 3 000 mg/kg, after verification. In some cases it may be possible to extend the range up to 5 000 mg/kg depending on element, wavelength, arc parameter, and sample weight. 2 Principle The combustion and evaporation of the crushed sample material takes place in the arc in an atmosphere of mixed argon and oxygen or in air. The metallic traces in the arc plasma are excited to emission of light. The light is guided into a simultaneous emission spectrometer (e.g. by coupling via fibre-optics or directly). The light is split in its spectral lines and measured by applicable detectors like a photomultiplier, charge coupled device (CCD), and charge injection device (CID). The mass fractions of elements in the sample are calculated by comparison of the intensities of the element-specific spectral line with those of a calibration sample of identical material. 3 Spectrometry The optical emission spectrometry is based on generation of line spectra of excited atoms or ions, in which each spectral line can be definitely related to an element and the line intensities are proportional to the mass fractions of elements in the measured sample (see [6], [7] & [12]). Contrary to wet-chemical methods via solution the classical sample decomposition is replaced by evaporation end excitation in DC-Arc. 4 Apparatus Ordinary laboratory apparatus and the following: 4.1 Emission spectrometer, simultaneous, preferably with time resolved registration of signal, and connected to DC-Arc-equipment. 4.2 Gas flushing device, for shielding gas and/or reaction gas of DC-Arc, e.g. gas-mixer with mass-flow controller and Stallwood-jet NOTE When working with air, the shielding gas unit can be omitted. 4.3 Tweezers, self-locking. 4.4 Balance, an analytical balance at least capable of reading to the nearest 0,1mg. However, for small weight <10 mg, a five figure balance at least capable of reading to the nearest 0,01 mg shall be used. 4.5 Pressing tool, for compacting the sample into the electrode. SIST EN 15979:2011

Only analytical grade reagents shall be used unless stated otherwise. 5.1 High resistance carbon electrodes or graphite electrodes, spectral-grade, peak-shaped or elliptical counter electrode (cathode), cup-shaped carrier electrode (anode) with groove or taper. 5.2 Calibration samples with well-defined mass fractions of trace-impurities, preferably certified reference materials (CRM) NOTE Certified reference materials for main- minor- and trace constituents are available for e.g. silicon nitride, Silicon Carbide and Boron Carbide. A listing of certified reference materials is given in Annex E. 5.3 Oxygen purity ≥ 99,99 % (volume fraction) 5.4 Argon purity ≥ 99,99 % (volume fraction) 6 Sampling and preparation of test samples
Sampling of test samples shall be representative for the total quantity of material, using for example ISO 5022 [13], ISO 8656-1 [14], EN ISO 21068-1 [15] but this list is not exhaustive.
If the sample is not received in a dry state, it shall be dried at (110 ± 10) °C until constant mass is achieved
(< 0,5 % variation). The sample is then cooled down to room temperature and stored in a desiccator.
NOTE Drying for 2 h is normally sufficient. The particle size of sample material shall be ≤ 160 µm. If necessary it has to be crushed and homogenized. Choose the crushing device according to the analysis task.
7 Calibration Calibration shall be carried out for each measuring cycle (minimum once per day) with calibration samples (5.2) of defined mass fractions of traces-impurities in accordance with Clause 8. Calibration shall be performed at the beginning and at the end of the measuring cycle. Within the calibration range at least a three-point calibration shall be performed (see [4], [8]).
Calibration samples (5.2) of identical or similar material, if possible certified reference materials or matrix matched synthetic calibration samples, shall be used. The mass fractions of trace-impurities in the calibration samples should be in the range of the sample material (see Annex E).
8.1 Standard procedure The sample prepared in accordance with Clause 6 is filled into the carrier electrode. Alternatively the three following procedures (a to c) can be applied. a) The sample material is filled into the carrier electrode using a small, precisely tailored funnel and applying mechanical compression; b) The carrier electrode is filled by repeatedly pressing the cup (orifice downwards) onto the sample material which is lying on a clean carrier (e.g. filter paper); c) A sub-sample of the sample material is weighed to the nearest ± 0,1 mg into the carrier electrode in a defined narrow weighing range (e.g. between 4,5 to 5,5 mg). The mass of the weighed sub-sample has to be documented. Depending on dimension and shape of the carrier electrode the mass of the sub-sample can vary. The sample mass can be reduced in case of elements, e.g. with mass fractions above the calibration range (minimum circa 1 mg). In this case, the weighed sub-sample has to be mixed in the electrode with a material of the same type, which does not contain the respective analytes. The total mass of material in the electrode shall correspond to that of the calibration sample (5.2). Instead of a pure material of the same type spectral-grade carbon powder can be used.
Subsequently, the sub-sample has to be compacted in the cup of the carrier electrode by slightly striking it on a rigid underlay or by knocking with a spatula at the tweezers holding the carrier electrode. The electrodes shall be touched in the clamp-region of the electrode holder using tweezers (4.3)
The carrier electrode has to be fixed in the optical path using the electrode holder of the DC-Arc equipment. The distance to the upper counter electrode (cathode) has to be adjusted to the nearest ± 0,1 mm at a value of 3,5 mm to 4,0 mm. NOTE 1 The distance between the electrodes can vary according to the diameter of the electrodes. The position of the electrodes, and thus the arc discharge, has to be constant with respect to the optical axis of the optical system. Any change of th
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