SIST EN 15991:2016
(Main)Testing of ceramic and basic materials - Direct determination of mass fractions of impurities in powders and granules of silicon carbide by inductively coupled plasma optical emission spectrometry (ICP OES) with electrothermal vaporisation (ETV)
Testing of ceramic and basic materials - Direct determination of mass fractions of impurities in powders and granules of silicon carbide by inductively coupled plasma optical emission spectrometry (ICP OES) with electrothermal vaporisation (ETV)
This European Standard defines a method for the determination of the trace element concentrations of Al, Ca, Cr, Cu, Fe, Mg, Ni, Ti, V and Zr in powdered and granular silicon carbide.
Dependent on element, wavelength, plasma conditions and weight, this test method is applicable for mass contents of the above trace contaminations from about 0,1 mg/kg to about 1 000 mg/kg, after evaluation also from 0,001 mg/kg to about 5 000 mg/kg.
NOTE 1 Generally for optical emission spectrometry using inductively coupled plasma (ICP OES) and electrothermal vaporisation (ETV) there is a linear working range of up to four orders of magnitude. This range can be expanded for the respective elements by variation of the weight or by choosing lines with different sensitivity.
After adequate verification, the standard is also applicable to further metallic elements (excepting Rb and Cs) and some non-metallic contaminations (like P and S) and other allied non-metallic powdered or granular materials like carbides, nitrides, graphite, soot, coke, coal, and some other oxidic materials (see [1], [4], [5], [6], [7], [8], [9] and [10]).
NOTE 2 There is positive experience with materials like for example graphite, B4C, Si3N4, BN and several metal oxides as well as with the determination of P and S in some of these materials.
Prüfung keramischer Roh- und Werkstoffe - Direkte Bestimmung der Massenanteile von Spurenverunreinigungen in pulver- und kornförmigem Siliciumcarbid mittels optischer Emissionsspektroskopie mit induktiv gekoppeltem Plasma (ICP OES) und elektrothermischer Verdampfung (ETV)
Diese Europäische Norm legt ein Verfahren zur Bestimmung der Gehalte der Spurenelemente Al, Ca, Cr, Cu, Fe, Mg, Ni, Ti, V und Zr in pulver- und kornförmigem Siliciumcarbid fest.
Das festgelegte Prüfverfahren gilt in Abhängigkeit von Element, Wellenlänge, Plasmabedingungen und Einwaage für Massenanteile der o. g. Spurenverunreinigungen von etwa 0,1 mg/kg bis etwa 1 000 mg/kg, nach Prüfung auch von 0,001 mg/kg bis etwa 5 000 mg/kg.
ANMERKUNG 1 In der Regel gilt für die optische Emissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP OES) und elektrothermischer Verdampfung (ETV) ein linearer Arbeitsbereich von bis zu vier Größenordnungen. Dieser Bereich kann für die einzelnen Elemente durch Änderung der Einwaage oder durch die Auswahl verschieden empfindlicher Linien erweitert werden.
Nach entsprechender Prüfung ist die Norm auch auf weitere metallische Elemente (mit Ausnahme von Rb und Cs) und einige nichtmetallische Verunreinigungen (wie z. B. P und S) und andere artverwandte nichtmetallische pulver und kornförmige Werkstoffe, wie z. B. Carbide, Nitride, Graphit, Ruß, Koks, Kohle, sowie eine Reihe weiterer oxidischer Werkstoffe anwendbar (siehe [1], [4], [5], [6], [7], [8], [9] und [10]).
ANMERKUNG 2 Es liegen positive Erfahrungen zu Werkstoffen, wie z. B. Graphit, B4C, Si3N4, BN und verschiedenen Metalloxiden sowie zur Bestimmung von P und S in einigen dieser Werkstoffe vor.
Essais sur matériaux céramiques et basiques - Détermination directe des fractions massiques d'impuretés dans les poudres et les granulés de carbure de silicium par spectroscopie d'émission optique à plasma induit par haute fréquence (ICP OES) avec vaporisation électrothermique (ETV)
La présente Norme définit une méthode pour la détermination de concentrations d'éléments traces d'Al, Ca, Cr, Cu, Fe, Mg, Ni, Ti, V et Zr dans les poudres et les granulés de carbure de silicium.
Selon l’élément, la longueur d’onde, les conditions de plasma et le poids, cette méthode d’essai s’applique à des teneurs en masse des contaminants à l’état de traces précédemment mentionnés comprises entre 0,1 mg/kg environ et 1 000 mg/kg environ, après évaluation, également comprises entre 0,001 mg/kg et 5 000 mg/kg environ.
NOTE 1 Pour la spectroscopie d’émission optique avec plasma induit par haute fréquence (ICP OES) et la vaporisation électrothermique (ETV), on dispose généralement d’une plage de fonctionnement linéaire allant jusqu'à quatre ordres de grandeur. Cette plage peut être étendue pour les éléments respectifs en changeant le poids ou en choisissant des raies de sensibilité différente.
Après vérification adéquate, la présente Norme est également applicable à d’autres éléments métalliques (excepté Rb et Cs), à certains contaminants non métalliques (tels que P et S) et à d’autres matériaux non métalliques voisins sous forme de poudres ou de granulés, tels que les carbures, les nitrures, le graphite, la suie, le coke, le charbon, et à certains autres matériaux obtenus par oxydation (voir [1], [4], [5], [6], [7], [8], [9] et [10]).
NOTE 2 L’expérience s’avère positive avec des matériaux comme le graphite, B4C, Si3N4, BN, par exemple, et plusieurs oxydes métalliques et en déterminant le P et le S dans certains de ces matériaux.
Preskušanje keramičnih surovin in osnovnih materialov - Neposredno določevanje masnih frakcij nečistoč v prahu in zrnih silicijevega karbida z optično emisijsko spektroskopijo in induktivno sklopljeno plazmo (ICP OES) z elektrotermičnim uparevanjem (ETV)
Ta evropski standard opisuje metodo za določevanje koncentracij elementov v sledovih za Al, Ca, Cr, Cu, Fe, Mg, Ni, Ti, V in Zr v prahu in zrnih silicijevega karbida.
Odvisno od elementa, valovne dolžine, pogojev plazme in teže, se ta preskusna metoda uporablja za masne frakcije nečistoč nad ravnjo sledi od približno 0,1 mg/kg do približno 1 000 mg/kg, po ocenjevanju tudi od 0,001 mg/kg do približno 5 000 mg/kg.
OPOMBA 1: Splošno imata optična emisijska spektrometrija z induktivno sklopljeno plazmo (ICP OES) in elektrotermično uparjevanje (ETV) linearno delovno območje z do štirimi velikostnimi razredi. To območje je mogoče razširiti za zadevne elemente s spreminjanjem teže ali z izbiro linij z različnimi občutljivostmi.
Po zadostnem preverjanju se lahko standard uporablja tudi za druge kovinske elemente (z izjemo Rb in Cs) in nekatere nekovinske nečistoče (kot sta P in S) ter druge povezane nekovinske materiale v prahu in zrnih, kot so karbidi, nitridi, grafit, saje, premog, koks in nekateri drugi oksidni materiali (glejte [1], [4], [5], [6], [7], [8], [9] in [10]).
OPOMBA 2: Pozitivne izkušnje obstajajo za materiale, kot so grafit, B4C, Si3N4, BN in nekateri kovinski oksidi, ter za določevanje P in S v nekaterih od teh materialov.
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.RWHUPLþQLPPrüfung keramischer Roh- und Werkstoffe - Direkte Bestimmung der Massenanteile von Spurenverunreinigungen in pulver- und kornförmigem Siliciumcarbid mittels optischer Emissionsspektroskopie mit induktiv gekoppeltem Plasma (ICP OES) und elektrothermischer Verdampfung (ETV)Essais sur matériaux céramiques et basiques - Détermination directe des fractions massiques d'impuretés dans les poudres et les granulés de carbure de silicium par spectroscopie d'émission optique à plasma induit par haute fréquence (ICP OES) avec vaporisation électrothermique (ETV)Testing of ceramic and basic materials - Direct determination of mass fractions of impurities in powders and granules of silicon carbide by inductively coupled plasma optical emission spectrometry (ICP OES) with electrothermal vaporisation (ETV)81.060.10SurovineRaw materialsICS:Ta slovenski standard je istoveten z:EN 15991:2015SIST EN 15991:2016en,fr,de01-januar-2016SIST EN 15991:2016SLOVENSKI
STANDARDSIST EN 15991:20111DGRPHãþD
SIST EN 15991:2016
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15991
November
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z sä r x rä s r Supersedes EN
s w { { sã t r s sEnglish Version
Testing of ceramic and basic materials æ Direct determination of mass fractions of impurities in powders and granules of silicon carbide by inductively coupled Essais sur matériaux céramiques et basiques æ Détermination directe des fractions massiques d 5impuretés dans les poudres et les granulés de carbure de silicium par spectroscopie d 5émission
Prüfung keramischer Rohæ und Werkstoffe æ Direkte Bestimmung der Massenanteile von Spurenverunreinigungen in pulveræ und kornförmigem Siliciumcarbid mittels optischer Emissionsspektroskopie mit induktiv gekoppeltem This European Standard was approved by CEN on
u October
t r s wä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey andUnited Kingdomä
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9
t r s w CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s w { { sã t r s w ESIST EN 15991:2016
EN 15991:2015 (E) 2 Contents Page European foreword . 3 1 Scope . 4 2 Principle . 4 3 Spectrometry . 4 4 Apparatus . 6 5 Reagents and auxiliary material . 6 6 Sampling and sample preparation . 7 7 Calibration . 7 8 Procedure. 8 9 Wavelength and working range . 9 10 Calculation of the results and evaluation . 9 11 Reporting of results . 10 12 Precision . 10 12.1 Repeatability . 10 12.2 Reproducibility . 10 13 Test report . 10 Annex A (informative)
Results of interlaboratory study . 11 Annex B (informative)
Wavelength and working range . 16 Annex C (informative)
Possible interferences and their elimination . 17 Annex D (informative)
Information regarding the evaluation of the uncertainty of the mean value . 20 Annex E (informative)
Commercial certified reference materials . 21 Annex F (informative)
Information regarding the validation of an analytical method based on liquid standards in the example of SiC and graphite. 22 Bibliography . 24
SIST EN 15991:2016
EN 15991:2015 (E) 3 European foreword This document (EN 15991:2015) has been prepared by Technical Committee CEN/TC 187 “Refractory products and materials”, the secretariat of which is held by BSI. 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 May 2016 and conflicting national standards shall be withdrawn at the latest by May 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 15991:2011. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
SIST EN 15991:2016
EN 15991:2015 (E) 4 1 Scope This European Standard defines a method for the determination of the trace element concentrations of Al, Ca, Cr, Cu, Fe, Mg, Ni, Ti, V and Zr in powdered and granular silicon carbide. Dependent on element, wavelength, plasma conditions and weight, this test method is applicable for mass contents of the above trace contaminations from about 0,1 mg/kg to about 1 000 mg/kg, after evaluation also from 0,001 mg/kg to about 5 000 mg/kg. NOTE 1 Generally for optical emission spectrometry using inductively coupled plasma (ICP OES) and electrothermal vaporization (ETV) there is a linear working range of up to four orders of magnitude. This range can be expanded for the respective elements by variation of the weight or by choosing lines with different sensitivity. After adequate verification, the standard is also applicable to further metallic elements (excepting Rb and Cs) and some non-metallic contaminations (like P and S) and other allied non-metallic powdered or granular materials like carbides, nitrides, graphite, soot, coke, coal, and some other oxidic materials (see [1], [4], [5], [6], [7], [8], [9] and [10]). NOTE 2 There is positive experience with materials like, for example, graphite, B4C, Si3N4, BN and several metal oxides as well as with the determination of P and S in some of these materials. 2 Principle The sample material, crushed if necessary, is evaporated in an argon- carrier-gas stream in a graphite boat in the graphite tube furnace of the ETV unit. The evaporation products containing the element traces are transported as a dry aerosol into the plasma of the ICP-torch and there excited for the emission of optical radiation. In a simultaneous emission spectrometer in, for example Paschen-Runge- or Echelle-configuration, the optical radiation is dispersed. The intensities of suited spectral lines or background positions are registered with applicable detectors like photomultipliers (PMT), charge coupled devices (CCD), charge injection devices (CID), and serial coupled devices (SCD). By comparison of the intensities of the element-specific spectral lines of the sample with calibration samples of known composition, the mass fractions of the sample elements are determined. 3 Spectrometry Optical emission spectrometry is based on the generation of line spectra of excited atoms or ions, where each spectral line is associated with an element and the line intensities are proportional to the mass fractions of the elements in the analysed sample. Contrary to the wet chemical analysis from dilution in ICP OES the classical sample digestion is replaced by electrothermal vaporization at high temperatures in a graphite furnace. By a suitable design of the furnace (see Figures 1 and 2) and a suited gas regime in the transition area graphite tube / transport tube (see Figure 1), it is ensured that the sample vapour is carried over into a form that is to transport effectively (see [5], [6], [7], [8], [10]). Carbide forming elements, for example titanium, zirconium, that are incompletely or not evaporating need a suitable reaction gas (halogenating agent) to be converted into a form that is easy to transport (see [1], [3], [5] and [10].) Dichlorodifluoromethane (CCl2F2) shall be used as halogenating agent. Compared to other halogen containing carbon compounds CCl2F2 provides optimum analyte release and transport efficiency. CCl2F2 is required for simultaneous determination of the elements listed in Clause 1. The results of the interlaboratory study (see Annex A) were obtained using CCl2F2 as reaction gas. The dry aerosol is introduced into the ICP plasma by the injector tube and there excited for the emission of light (see Figure 1, Figure 2 and Figure 3). SIST EN 15991:2016
EN 15991:2015 (E) 5
Key 1 graphite tube with boat and sample 5 bypass gas (Ar) 2 carrier gas (Ar) 6 aerosol 3 reaction gas (CCl2F2) 7 to the ICP torch 4 shield gas (Ar)
Figure 1 — Schematic configuration of the ETV-gas regime with the gas flows carrier-gas, bypass-gas, reaction-gas and shield-gas
Key 1 graphite tube furnace 6 bypass-gas (Ar) 2 pyrometer 7 aerosol 3 carrier gas (Ar) + reaction gas (CCl2F2) 8 transport tube 4 solid sample 9 ICP-torch 5 vapour 10 power supply 0 A to 400 A Figure 2 — Schematic design of the ETV-ICP-combination with an axial plasma (example) SIST EN 15991:2016
EN 15991:2015 (E) 6
Key 1 Al2O3-transport tube 5 carrier gas evaporated sample 2 Al2O3-transition ring 6 bypass gas 3 nozzle 7 gas mixture in laminar flow 4 graphite tube
Figure 3 — Schematic configuration of the transition area between graphite- and transport-tube NOTE Figure 1, Figure 2 and Figure 3 show a well-established commercial instrument. 4 Apparatus 4.1 Common laboratory instruments and laboratory instruments according to 4.2 to 4.7. 4.2 ICP-emission spectrometer, simultaneous, preferably with the possibility to register transient emission signals and suited for the synchronised start of ETV vaporization cycle and signal registration. NOTE Especially for changing matrices the measurement of the spectral background near the analysis lines is beneficial, because by this the systematic and stochastic contributions of the analysis uncertainty can be decreased, the latter only by simultaneous measurement of the background. The use of spectrometers equipped with area- or array-detectors is an advantage in such cases as they allow a simultaneous background measurement, in addition to their possibility to save a lot of time in the analysis cycle. 4.3 Electrothermal vaporization system with graphite furnace with suited transition zone graphite tube / transport tube for optimised aerosol formation, to be connected to the injector tube of the ICP torch by a transport tube for example made of corundum, PTFE, PFA, PVC (cross-linked), with controlled gas flows (preferably with mass-flow-control) and furnace control (preferably with continuous online-temperature control of the graphite boat) for a reproducible control of the temperature development. 4.4 Tweezers, self-closing, made of a material preventing contamination. 4.5 Micro spatula, made of a material preventing contamination. 4.6 Microbalance, capable of reading to the nearest 0,01 mg. NOTE A microbalance with a direct reading of 0,001 mg is advantageous. 4.7 Mill or crusher, free of contamination, for example mortar made of a material that does not contaminate the sample with any of the analytes to be determined. 5 Reagents and auxiliary material Only analytical grade reagents shall be used unless stated otherwise. SIST EN 15991:2016
EN 15991:2015 (E) 7 5.1 Sample boats of graphite (spectral grade) adapted in size to the graphite tube of the ETV, baked out for the necessary purity. 5.2 Calibration samples with well-defined mass fractions of trace-impurities, preferably certified reference materials (CRM). NOTE For silicon nitride, silicon carbide and boron carbide certified reference material is available for main-, minor- and trace-components. (For CRMs, see Annex E.) 5.3 Calibration solutions, made of tested stock solutions of the elements to be analysed. 5.4 Reaction gas, Dichlorodifluoromethane (CCl2F2). NOTE Dichlorodifluoromethane is the most effective reaction gas, some alternative reaction gases have serious disadvantages. According to the EU-regulation (see [12]) of materials influencing the ozone layer, this chemical product is allowed for laboratory use and for the use as a starting substance. CCl2F2 is completely decomposed in the hot graphite furnace and in the downstream inductively coupled plasma. The use of CCl2F2 for laboratory and analysis purposes is subject to registration at the European Commission. 5.5 Argon purity
99,99 % (volume fraction). 6 Sampling and sample preparation Sampling shall be performed in a way that the sample to be analysed is representative for the total amount 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. It is critical that the sample material is on hand at a particle size of
50 µm; eventually it shall be broken up and homogenized, if necessary. For this a crushing device suited for the analysis goal shall be applied. For porous materials, it shall be checked out if it is necessary to break them up. Breaking up is necessary if the transient analysis signals show an unusual long decay (tailing). 7 Calibration The calibration shall be performed for each measuring cycle with calibration samples with defined analyte concentrations. The procedure shall be carried out in accordance with Clause 8. The calibration shall be carried out over a range adapted to the analytical task. NOTE 1 This can be achieved by different masses of the same calibration sample or same masses of different calibration samples with different analyte concentration or by a combination of both possibilities. Because of the low weights used and therefore the resulting spread, the number of (calibration) measurements should take account of the desired accuracy. Practically about 10 to 15 standards have been found to be ideal; e.g. for 10, five weights of two different calibration samples with different analyte concentrations are required. Preferably calibration samples of the same or similar material should be used, if possible certified reference materials (CRM) or matrix-adapted synthetic calibration samples. SIST EN 15991:2016
EN 15991:2015 (E) 8 The trace concentrations of the calibration samples should be in the same range as of the sample material.
Dependent on the grain size distribution of the sample, the material properties of the material to be analysed and the analytical performance of the used ETV-system for certain analytes and matrices also dried aqueous calibration standards with or without matrix adaptation may be used (see [1], [6] to [9] and Annex F). In the concrete case this shall be documented by calibration substances or certified reference materials. If such materials are not available the results of alternative analysis methods can be used for comparison. NOTE 2 For aqueous calibration with matrix adaptation so-called blank samples are suitable, i.e. materials with the same matrix as the sample and with concentrations negligible compared to the expected analyte concentration in the sample. The blank sample is weighed with a mass comparable to the sample to be analysed, then the aqueous calibration solution is added. NOTE 3 The calculation of the calibration function is usually carried out as linear regression. The calculated data are displayed graphically as calibration function. Eventually also a quadratic regression is applicable. The continuous slope of the calibration function with a sufficient gradient is important. 8 Procedure Use the sample prepared according to Clause 6 and weigh, preferably between 1 mg and 5 mg with a precision of 0,01 mg into the sample boats; baked out in advance. The baking-out temperature for cleaning the boats shall be approximately 100 °C above the highest temperature of the analysis run. Dependent on the material, the analyte, the analyte concentration, the chosen lines and the ETV-system higher weights may be used. The applied part sample weight shall be documented. The ICP-emission-spectrometer (4.2) shall be set up in accordance with its operations manual. After an adequate waiting time (20 min is normal) the first boat is applied into the furnace of the ETV-system by tweezers (4.4) or by an auto sampler device. The analysis programme is started, while the control of the temperature run of the furnace of the ETV-system and the registration of the emission signals in the spectrometer shall be triggered simultaneously. After the end of the analysis programme the sample boat is removed from the furnace of the ETV by tweezers or by an automatic auto sampler device and the next one is brought in. Before the actual analysis run the blank value of the system shall be determined with an empty, cleaned boat. With another empty, clean boat and a certain amount of calibration sample or dried calibration solution the integration intervals of the chosen emission lines and the background positions shall be checked for their optimum position and eventually are corrected. For each material a special temperature programme shall be created depending on the analyses. The programme creation preferably should be done using available calibration standards. They also should be used to choose the suitable emission lines. Before configuring the integration – respectively the analysis – interval the release of the analyses shall be observed by recording the transient emission signals. SIST EN 15991:2016
EN 15991:2015 (E) 9 EXAMPLE Furnace programme for the matrix SiC: Conditioning step: 3 s heating-up from room temperature to 450 °C, dwell 27 s at 450 °C; Vaporization step: 3 s heating-up to 2 300 °C, dwell 27 s at 2 300 °C; Cooling-off time: 50 s cooling down to room temperature. The cooling-off rate is dependent on the performance of the used chillier. Before changing the boat the temperature should be < 200 °C. Integration interval: 31 s to 52 s after the start of the furnace programme; Total integration time:
21 s. Each sample shall be measured several times, but at least 3 times. If the single values of the multiple analysis of the analyte concentrations deviate by more than a given degree, depending on the repeatability of the method, then the analysis shall be repeated according to Clause 8. If poor reproducibility of the spectral intensities of one or more analytes of the sample persists, it is necessary to homogenize the sample further, e.g. in a mortar. For low concentrations, near the limit of determination (see [16]) this additional step is not necessary. 9 Wavelength and working range When selecting the wavelength of analytes, it should be borne in mind that these shall be inference free with respect to sample matrix and further impurities. Only spectral lines shall be selected where under the chosen working conditions neither self-absorption nor self-reversal can occur. NOTE 1 Proposal for choosing of wavelength and information about working ranges, see Annex B. NOTE 2 A summary description of interferences and possibilities to reduce these is in Annex C. When setting up the analytical programme for a specific material, ensure via suitable pre-tests that the analytical ranges lie above the limit of determination of the analytes. The upper working range is restricted by decrease of sensitivity (slope of calibration graph) to about 80 % of its initial value. Where appropriate the line used can be changed to a less sensitive spectral line. 10 Calculation of the results and evaluation The intensities of spectral lines measured by the emission spectrometer are to be corrected to net-intensities via background intensities measured at the background measuring points. Using the analytical functions the corrected net-intensities are to be converted into the corresponding masses of the respective analyte (see Clause 8). Using the sample weight of sub-sample the mass fractions of analytes in the sample shall be calculated. NOTE To improve precision and trueness the method of internal standard (reference element) can be applied. For this purpose, the ratio of intensities of spectral lines of analyte elements to the intensity of the spectral line of a reference element (e.g. Si in analysis of SiC) is used. The wavelengths of used spectral lines and background measuring points for calibration and for measurement of the sample itself shall always be the same. SIST EN 15991:2016
EN 15991:2015 (E) 10 11 Reporting of results The concentration shall be reported as the mean of the individual determinations carried out, expressed as a % m/m. Results shall be rounded to the nearest 0,01 % or the uncertainty of measurement (see Annex D), whichever is the greater. 12 Precision NOTE See ISO 5725-2 [17] for definitions. 12.1 Repeatability The repeatability limit r will not be exceeded in more than 5 % of cases by the absolute difference between two single test results independent of each other and determined at the same sample material by the same analyst using the same analytical procedure and the same equipment in the same laboratory within a short time. The data of repeatability determined at three different silicon carbide samples in the frame of an interlaboratory comparison are listed in Annex A. 12.2 Reproducibility The reproducibility limit R will not be exceeded in more than 5 % of cases by the absolute difference between two single test results determined by different analysts analysing the same sample material using the same analytical procedure and different equipment in different laboratories. The reproducibility data determined using three different silicon carbide samples in the frame of an interlaboratory comparison are listed in Annex A. 13 Test report
Test reports shall include the following information: a) designation of the sample tested; b) a reference to this European Standard; c) test results, expressed as mean of the single values of multiple determinations according to Clause 11; d) if required, uncertainty of mean (see Annex D) or standard deviation; e) if required, information for calibration; f) if any discrepancy from this standard (observed during the test); g) name and address of laboratory, analysis date and, if required, signature of the responsible person. SIST EN 15991:2016
EN 15991:2015 (E) 11 Annex A (informative)
Results of interlaboratory study The interlaboratory study was carried out using six different SiC samples. The analyte concentration (mass fractions) of each individual sample was calculated on the basis of the analytical functions obtained by the other five samples. This procedure was carried out for three selected silicon carbide samples and the results were used for evaluation of statistical data. The maximum grain size of all samples was less than 50 µm. The evaluation of results was carried out according to ISO 5725-2 [17]. SIST EN 15991:2016
EN 15991:2015 (E) 12 Table A.1 — Data of precision determined at the SiC-sample nmp1 Analyte
Total mean values Variance of Repeat-ability Repeatabilitystandard deviation Repeatability limit Coefficient of variation of repeatability Reproducibility standard deviation Reproducibility limit Coefficient of variation of reproducibility
pa Aw 2rs rs r rv Rs R Rv
mg/kg mg/kg mg/kg mg/kg % relative mg/kg mg/kg % relative Al 10 94,47 79,59 8,92 24,98 9,44 12,35 34,57 13,07 Ca 9 3,13 0,34 0,58 1,62 18,49 0,89 2,50 28,51 Cr 8 2,48 0,13 0,36 1,01 14,52 0,51 1,43 20,55 Cu 10 0,82 0,03 0,18 0,50 21,53 0,27 0,74 32,26 Fe 10 279,45 316,15 17,78 49,79 6,36 23,76 66,51 8,50 Mg 10 3,18 0,18 0,43 1,20 13,50 0,49 1,37 15,40 Ni 10 71,69 54,12 7,36 20,60 10,26 9,47 26,51 13,21 Ti 9 141,63 123,51 11,11 31,12 7,85 18,04 50,51 12,74 V 10 138,61 296,52 17,22 48,21 12,42 22,21 62,18 16,02 Zr 10 22,00 3,55 1,88 5,28 8,57 1,85 5,18 8,41 a Number of participants for the element. SIST EN 15991:2016
EN 15991:2015 (E) 13 Table A.2 — Data of precision determined at the SiC-sample 628 Analyte
Total mean values Variance of Repeatability Repeatabilitystandard deviation Repeatability limit Coefficient of variation of repeatability Reproducibility standard deviation Reproducibility limit Coefficient of variation of reproducibility
pa Aw 2rs rs r rv Rs R Rv
mg/kg mg/kg mg/kg mg/kg % relative mg/kg mg/kg % relative Al 10 284,21 516,50 22,73 63,63 8,00 34,45 96,45 12,12 Ca 9 22,33 1,69 1,30 3,64 5,82 1,96 5,48 8,77 Cr 8 3,76 0,11 0,33 0,93 8,86 0,57 1,60 15,18 Cu 10 3,13 0,09 0,29 0,82 9,37 0,32 0,89 10,20 Fe 10 414,90 798,73 28,26 79,13 6,81 27,23 76,26 6,56 Mg 10 2,14 0,20 0,45 1,25 20,86 0,56 1,57 26,19 Ni 10 99,66 59,59 7,72 21,61 7,75 8,66 24,25 8,69 Ti 9 88,52 56,52 7,52 21,05 8,49 8,13 22,76 9,18 V 10 418,52 2488,61 49,89 139,68 11,92 48,81 136,66 11,66 Zr 10 13,79 2,91 1,71 4,78 12,37 1,95 5,46 14,14 a Number of participants for the element. SIST EN 15991:2016
EN 15991:2015 (E) 14 Table A.3 — Data of precision determined at the SiC-sample 8517 certified later as reference material BAM-S003 Analyte
Total mean values Variance of Repeat-ability Repeatabilitystandard deviation Repeatability limit Coefficient of variation of repeatability Reproducibility standard deviation Reproducibility limit Coefficient of variation of reproducibility Certified values for comparison Certified expanded uncertainty U
pa Aw 2rs rs r rv Rs R Rv
(k
= 2) b
mg/kg mg/kg mg/kg mg/kg % relative mg/kg mg/kg % relative mg/kg mg/kg Al 10 352,51 476,02 21,82 61,09 6,19 26,33 73,71 7,47 372 20 Ca 9 27,30 4,92 2,22 6,21 8,13 2,56 7,17 9,38 29,4 1,8 Cr 8 3,46 0,17 0,42 1,17 12,07 0,47 1,31 13,49 3,5 0,4 Cu 10 1,22 0,01 0,10 0,27 7,88 0,15 0,41 11,94 1,5 0,4 Fe 10 161,20 103,88 10,19 28,54 6,32 14,49 40,58 8,99 149 10 Mg 10 5,62 0,21 0,46 1,30 8,24 0,61 1,70 10,83 6,3 0,6 Ni 10 36,17 4,69 2,17 6,07 5,99 3,02 8,47 8,36 32,9 2,7 Ti 9 91,56 30,35 5,51 15,42 6,02 10,32 28,90 11,27 79 4 V 10 41,99 46,40 6,81 19,07 16,22 9,50 26,59 22,61 41,4 2,8 Zr 10 23,06 3,15 1,77 4,97 7,69 2,36 6,60 10,23 25,2 2 a Number of participants for the element. b CRM BAM-S003. SIST EN 15991:2016
EN 15991:2015 (E) 15 Table A.4 — Statistical results summarized in intervals Analyte
Interval of mass fractions Repeatability standard deviation Repeatability limit Coefficient of variation of repeatability Reproducibilitystandard deviation Reproducibility limit Coefficient of variation
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