1、June 2007DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 71.040.40; 81.080!,y60“98
2、61913www.din.deDDIN EN 12698-2Chemical analysis of nitride bonded silicon carbide refractories Part 2: XRD methodsEnglish version of DIN EN 12698-2:2007-06Chemische Analyse von feuerfesten Erzeugnissen aus nitridgebundenem Siliciumcarbid Teil 2: XRD-VerfahrenEnglische Fassung DIN EN 12698-2:2007-06w
3、ww.beuth.deDocument comprises 15 pages 09.07DIN EN 12698-2:2007-06 2 National foreword This standard has been prepared by CEN/TC 187 “Refractory products and materials“ (Secretariat: BSI, United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Materialprfung
4、(Materials Testing Standards Committee, Technical Committee NA 062-02-64 AA Chemische Analyse von nichtoxidischen keramischen Roh- und Werkstoffen. The DIN Standards corresponding to the International Standards referred to in the EN are as follows: ISO 565 DIN ISO 565 ISO 8656-1 DIN 51061-2, DIN EN
5、1402-2 National Annex NA (informative) Bibliography DIN 51061-2, Sampling of ceramic raw materials and refractory unmoulded products DIN EN 1402-2, Unshaped refractory products Part 2: Sampling for testing DIN ISO 565, Test sieves Metal wire cloth, perforated metal plate and electroformed sheet Nomi
6、nal sizes of openings EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12698-2March 2007ICS 71.040.40English VersionChemical analysis of nitride bonded silicon carbide refractories -Part 2: XRD methodsAnalyse chimique des produits rfractaires contenant dude DRXChemische Analyse von feuerfesten Erze
7、ugnissen ausnitridgebundenem Silicumcarbid - Teil 2: XRD-VerfahrenThis European Standard was approved by CEN on 15 February 2007.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
8、 without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other langu
9、age made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,F
10、rance, 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 STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR
11、NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12698-2:2007: Ecarbure de silicium liaison nitrure - Partie 2: MthodesEN 12698-2:2007 (E) 2 Contents Page Foreword .3
12、1 Scope 4 2 Normative references4 3 Definitions 4 4 Apparatus .4 5 Sampling.5 6 Procedure .5 6.1 Sample preparation .5 6.2 Measuring parameters 5 6.3 Qualitative analysis .5 6.4 Quantitative analysis.6 7 Precision.10 7.1 Repeatability 10 7.2 Reproducibility.10 8 Test report 10 Annex A (normative) X-
13、ray diffraction data for the determination of -SiAlON content.11 A.1 General .11 A.2 Example of calculation of z-value for -SiAlON 12 Bibliography13 EN 12698-2:2007 (E) 3 Foreword This document (EN 12698-2:2007) has been prepared by Technical Committee CEN/TC 187 “Refractory products and materials”,
14、 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 September 2007, and conflicting national standards shall be withdrawn at the latest by September 2007. Acc
15、ording to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lat
16、via, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12698-2:2007 (E) 4 1 Scope This standard describes methods for the determination of mineralogical phases typically apparent in nitride and oxy-nitr
17、ide bonded silicon carbide refractory products using a Bragg-Brentano diffractometer. It includes details of sample preparation and general principles for qualitative and quantitative analysis of mineralogical phase composition. Quantitative determination of -Si3N4, -Si3N4, Si2ON2, AlN, and SiAlON a
18、re described. NOTE For the refinement procedures the total nitrogen content, analysed in accordance with EN 12698-1 is needed. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For u
19、ndated references, the latest edition of the referenced document (including any amendments) applies. EN 12475-4:1998, Classification of dense shaped refractory products Part 4: Special products EN 12698-1, Chemical analysis of nitride bonded silicon carbide refractories Part 1: Chemical methods ISO
20、836:2001, Terminology for refractories ISO 5022, Shaped refractory products Sampling and acceptance testing ISO 8656-1, Refractory products Sampling of raw materials and unshaped products Part 1: Sampling scheme 3 Definitions For the purposes of this document the terms and definitions given in ISO 8
21、36:2001, EN 12475-4:1998 and the following apply. 3.1 nitride and oxynitride bonded silicon carbide refractories refractory products predominantly consisting of silicon carbide with minor amounts of nitride phases as a matrix component NOTE In general, metallic silicon is used as a precursor materia
22、l, which undergoes a phase transformation in an oxygen-free nitrogen atmosphere. 4 Apparatus Bragg-Brentano diffractometers with a copper X-ray tube, graphite monochromator and scintillation counter and the following experimental setting for data collection are used: goniometer with a measurement un
23、certainty of 0,5 at a confidence level of 95 %; primary soller slit with a divergence 2,5 ; divergence slit 1 ; receiving slit 0,2 mm; EN 12698-2:2007 (E) 5 scatter slit 1 ; narrow line focus; tube settings 40 kV and 20 mA to 45 mA. 5 Sampling Sample shaped and unshaped products using the procedures
24、 given in ISO 5022 and ISO 8656-1. When sampling large fragments, take care to collect samples from different points of individual pieces. Homogenize the sample by reducing the maximum particle size to 150 m and take the test sample from this material. 6 Procedure 6.1 Sample preparation Grind the sa
25、mple using a mill so that the resultant powder can pass through a 100 mesh sieve. NOTE Care should be taken not to grind the sample excessively as this has been found to cause the silicon nitride, and silicon phases in particular, to reduce in intensity. This is believed to be due to a build up of a
26、n amorphous layer on their particles due to damage induced by the silicon carbide. Press the powder into the cavity holder from the reverse side of the cavity to that which is to be presented to the x-ray beam (to reduce preferred orientation). The depth of the cavity shall be sufficient to exceed t
27、he critical depth of CuK radiation for the sample analysed. 6.2 Measuring parameters Scan the sample on the instrument using the following parameters: start angle, 2 10 ; end angle, 2 70 , 130 if -SiAlON determination is required; step-spec, 2 0,02 or continuous; integration time 4 s. An additional
28、scan using the same conditions as above between 60 and 70 2 may be required if aluminium and/or iron is thought to be present. NOTE Parameters for tube settings should be: voltage 40 kV, excitation current 20 mA to 45 mA. 6.3 Qualitative analysis Use an automatic or manual search to identify differe
29、nt phases in accordance with the ICDD, JCPDS and ASTM databases. NOTE 1 A deconvolution program should be used for overlapping peaks. EN 12698-2:2007 (E) 6 NOTE 2 The following phases are commonly found in nitride bonded silicon carbide: -SiC, -SiC, -Si3N4, -Si3N4, Si (free), Si2ON2, SiO2 (cristobal
30、ite), FeSi2 and WC (from grinding). Less common phases include: FeSi, Fe, Al, AlN, C (graphite), SiO2 (quartz), SiAlON. Some potential line overlaps to be aware of include the (111) cristobalite at 28,4 with the (111) silicon and the (110) iron at 44,7 with the (200) aluminium, there is also an inte
31、rference of monoclinic zirconia on silicon. 6.4 Quantitative analysis 6.4.1 General For quantitative analysis the net peak intensities of the test sample are compared to a sample of known concentration. The intensities shall be evaluated by measuring the peak height or preferably the peak area. For
32、the determination of the net peak intensity, deduct the background from the total peak intensity. Certified reference material(s) should be used where available. If no reference material is available chemical and mineralogical pure substances may be used instead. Calibration mixtures of 5 % and 10 %
33、 by mass in silicon carbide matrix shall be made up. Calibrations using the above mixes and one of 100 % by mass of silicon carbide by mass shall be constructed. The phases given in Table 1 can currently be quantified by XRD. For quantification, the peak positions listed in Table 1 shall be preferab
34、ly used. Ascertain that there are no line overlaps with other phases by performing a qualitative analysis in accordance with 6.3. Table 1 Phases which can currently be quantified by XRD Phase Available reference material Diffraction angle 2 degrees Miller Indices -Si3N4NIST656 BAM-S001 20,5 31,0 101
35、 201 -Si3N4NIST656 27,0 200 Si 28,4 47,3 56,0 111 220 311 Si2ON219,0 20,0 110 020 SiO2(cristobalite) NBS SRM 1879 21,9 101 FeSi2BCS 305/1 (50 % FeSi2, 50 % Si) 17,1 001 FeSi 28,0 69,4 79,9 110 311 321 Fe 44,7 82,3 110 211 Al 44,7 78,2 82,4 200 311 222 -SiC Used for calibration material NOTE 1 The li
36、mits of determination can be 5 % by mass even when using the recommended apparatus in clause 4 and measuring parameters in 6.2. EN 12698-2:2007 (E) 7 NOTE 2 Peak intensities should be measured as areas using computer software, taking into account peak overlaps where appropriate. Measuring the peak h
37、eight and the background by hand is also possible. NOTE 3 It can be appropriate to use mass absorption coefficients based on bulk chemistry in the calculation of components particularly when non silicon based components are present. If so, it should be noted in the test certificate. 6.4.2 Calculatio
38、n 6.4.2.1 General The net intensities are assumed to correlate linearly with the phase concentration. Therefore, the determination of the unknown phase concentration shall be calculated by the rule of proportion. Where more than one peak per phase is measured, a mean result shall be quoted. The amou
39、nt of each phase shall be taken from its individual calibration. 6.4.2.2 Calculation refinement for -Si3N4, -Si3N4, Si2ON2, and AlN The contents of -Si3N4, -Si3N4, Si2ON2, and AlN shall be normalized in proportion to their molecular nitrogen contents to the total nitrogen concentration. Determine th
40、e total nitrogen content in accordance with EN 12698-1. EXAMPLE By XRD, the following results were obtained. -Si3N41,0 % by mass; -Si3N42,0 % by mass; Si2ON23,0 % by mass. The total nitrogen was determined to be 2,10 % by mass from chemical methods (see EN 12698-1). Calculating the nitrogen content
41、from the XRD results gives: nitrogen from -Si3N4 = %0,40140,2956,031,00=by mass; nitrogen from -Si3N4= %0,80140,2956,032,00=by mass; nitrogen from Si2ON2= %0,84100,1928,023,00=by mass. Therefore the total nitrogen from XRD data = 2,04 % by mass; and therefore the correction factor is: 2,042,10which
42、gives the true nitride content as: -Si3N4 1,0 % by mass; -Si3N42,1 % by mass; Si2ON23,1 % by mass. EN 12698-2:2007 (E) 8 NOTE This method does not work if SiAlON or glassy phases of nitrogen are present. 6.4.2.3 Calculation refinement for -SiAlON content 6.4.2.3.1 Determination of composition As the
43、 composition of the -SiAlON is variable, it is necessary to first accurately determine the composition and then the amount of -SiAlON and other nitride or oxynitride components. The determination of composition or z-value is made by XRD, for the stoichiometric formula Si(6z)AlzOzN(8z). Accurately de
44、termine the peak positions of all non-overlapped -SiAlON peaks using an appropriate CRM or standard such as NBS SRM 640 silicon powder to check alignment. Reference the -SiAlON diffraction peaks on the basis of h, k, l Miller indices for a hexagonal structure. Annex A lists the calculated positions
45、for -SiAlON for z = 3, along with Miller indices and some potential overlap peaks. Calculate the nitrogen content of the -SiAlON using the z value to give the composition. EXAMPLE z = 1 Si(6z)AlzOzN(8z)Si5AlON7Nitrogen content = 34,8 % If no other nitride phases (-Si3N4, -Si3N4, AlN or SiON2) are pr
46、esent, determine the total nitrogen as in EN 12698-1, and calculate the -SiAlON content from the calculated nitrogen content of the SiAlON. For example: Total nitrogen 6 %, z value 1, nitrogen content of -SiAlON 34,8 % 100=NNS (1) where Sis the -SiAlON content, in %; N is the total nitrogen content,
47、 in %; N is the nitrogen content of -SiAlON, in %; i.e. %17,210034,86,0=S If other nitride phases are present, use XRD as described in Clause 6.4.1 and 6.4.2.2. Assign any residual nitrogen to SiAlON and determine the -SiAlON content. NOTE It is possible that normalizing to the total oxygen content
48、might not take into account the presence of silicate glass. Details of the X-ray diffraction data are given in Annex A. EN 12698-2:2007 (E) 9 6.4.2.3.2 Determination of z value Determine the cell parameters using appropriate methods; proprietary software or other techniques may be used. NOTE Cohens
49、least-squares method (see 6.4.2.3.3) is a suitable technique for a hexagonal SiAlON. From the a0and c0values, use the curves from Haviar and Johannesen 1 to determine the z value: ()0,2787,6050=az ()0,02482,910=cz If the values of z differ, take the arithmetic mean. Apply the z value to the SiAlON formula: Si(6z)AlzOzN(8z)6.4.2.3.3 Cohens Least Squares Method (Klung and Alexander (1959) 2).
