1、 DEUTSCHE NORM July 2006DIN EN 725-4 ICS 81.060.30 Supersedes DIN V ENV 725-4:1994-03 Advanced technical ceramics Methods of test for ceramic powders Part 4: Determination of oxygen content in aluminium nitride by XRF analysis English version of DIN EN 725-4:2006-07 Hochleistungskeramik Prfverfahren
2、 fr keramische Pulver Teil 4: Bestimmung des Sauerstoffgehaltes in Aluminiumnitridpulvern mittels Rntgenfluoreszenzanalyse (RFA) Englische Fassung DIN EN 725-4:2006-07 Document comprises 12 pages No part of this standard may be reproduced without prior permission of DIN Deutsches Institut fr Normung
3、 e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, has the exclusive right of sale for German Standards (DIN-Normen). English price group 8 www.din.de www.beuth.de !,p$H“11.06 9770137DIN EN 725-4:2006-07 2 National foreword This standard has been prepared by CEN/TC 184 Advanced technical cera
4、mics (Secretariat: United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee). However, at present a DIN committee does not exist for this standard since the parties concerned have not shown any interest in
5、work on the subject. Amendments This standard differs from DIN V ENV 725-4:1994-03 as follows: a) The foreword has been revised to reflect changes in the EN 725 standards series. b) The normative references have been updated. c) The requirements for the preparation of test pieces have been amended.
6、d) The test report has been amended. e) Bibliographical references have been included. f) The status of the prestandard has been changed to that of a full standard. Previous editions DIN V ENV 725-4: 1994-03 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 725-4 April 2006 ICS 81.060.30 Supersed
7、es ENV 725-4:1994 English Version Advanced technical ceramics - Methods of test for ceramic powders - Part 4: Determination of oxygen content in aluminium nitride by XRF analysis Cramiques techniques avances - Mthodes dessai pour poudres cramiques - Partie 4: Dtermination de la teneur en oxygne du n
8、itrure daluminium par spectromtrie de fluorescence XRF Hochleistungskeramik - Prfverfahren fr keramische Pulver - Teil 4: Bestimmung des Sauerstoffgehaltes in Aluminiumnitridpulvern mittels Rntgenfluoreszensanalyse (RFA) This European Standard was approved by CEN on 13 March 2006. CEN members are bo
9、und 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
10、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 translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status
11、 as the official versions. 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,
12、Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reserved worldwide for
13、CEN national Members. Ref. No. EN 725-4:2006: EEN 725-4:2006 (E) 2 Contents Page Foreword 3 1 Scope .5 2 Normative references .5 3 Principle.5 4 Apparatus and experimental conditions .5 4.1 Apparatus 5 4.2 Experimental conditions.5 5 Sample preparation.6 5.1 Granulometry 6 5.2 Test piece preparation
14、6 6 Calibration .6 6.1 Preparation of standards6 6.2 Calibration curves.6 6.3 Recalibration .7 6.4 Sensitivity limit of detection 7 7 Repeatability7 8 Test report .8 Bibliography.10 EN 725-4:2006 (E) 3 Foreword This European Standard (EN 725-4:2006) has been prepared by Technical Committee CEN/TC 18
15、4 “Advanced technical ceramics”, 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 October 2006, and conflicting national standards shall be withdrawn at the
16、 latest by October 2006. This European Standard supersedes ENV 725-4:1994. The main changes in the new edition are: - revision of the foreword to reflect changes in the EN 725 series; - changes to the normative references; - modification of the test piece preparation requirements; - modification of
17、the test report requirements; - addition of a bibliographical reference. EN 725 Advanced technical ceramics Methods of test for ceramic powders was prepared in Parts as follows: Part 1: Determination of impurities in alumina Part 2: Determination of impurities in barium titanate Part 3: Determinatio
18、n of oxygen content of non-oxides by thermal extraction with a carrier gas Part 4: Determination of oxygen content in aluminium nitride by XRF analysis Part 5: Determination of particle size distribution Part 6: Determination of specific surface area withdrawn Part 7: Determination of absolute densi
19、ty withdrawn Part 8: Determination of tapped bulk density Part 9: Determination of un-tapped bulk density Part 10: Determination of compaction properties Part 11: Determination of densification on natural sintering Part 12: Chemical analysis of zirconia Parts 6 and 7 of the series were superseded in
20、 2005 by EN ISO 18757 and EN ISO 18753 respectively. 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, EN 725-4:2006 (E) 4 Denmark, Estonia, Finla
21、nd, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 725-4:2006 (E) 5 1 Scope This European Standard specifies a method for the determ
22、ination of oxygen contents of 2 % or less in aluminium nitride powder, by XRF analysis. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the latest
23、edition of the referenced document (including any amendments) applies. EN 725-5, Advanced technical ceramics Methods of test for ceramic powders Part 5: Determination of particle size distribution EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/
24、IEC 17025:2005) EN ISO 18757, Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of specific surface area of ceramic powders by gas adsorption using the BET method (ISO 18757:2003) 3 Principle The sample is compacted to obtain a pellet, and the net intensity of the oxygen K
25、characteristic (I0K) of the pellet is measured by XRF spectrometer. The net intensity is the background intensity subtracted from the peak intensity at the peak position. The oxygen content in the sample is determined from this net intensity and by reference to previously defined calibration graphs;
26、 the calibration graph expresses the direct relation between net intensity and oxygen concentration. Calibration standards are prepared from different mixtures of fine aluminium nitride powder and a fine alumina powder. 4 Apparatus and experimental conditions 4.1 Apparatus Sequential X-ray fluoresce
27、nce spectrometer, equipped with a multilayer pseudo crystal and a gas flow proportional counter. NOTE For further details, see EN ISO 12677. 4.2 Experimental conditions The experimental conditions depend on the apparatus, with an example of good practice being as follows: a) Mode: vacuum b) Excitati
28、on: tube voltage: 30 kV tube current: 95 mA c) Spectrometer: crystal: multilayer pseudo crystal 2 d = 55 d) Peak: wavelength: 23,62 energy: 0,525 keV angular position: 51 2 (to be adjusted) EN 725-4:2006 (E) 6 e) Detection: detector type: gas flow proportional counter Ar-CH4or He-CO2pulse height sel
29、ection: the discriminate levels (Vmin, Vmax) should be set so as: Vmin, Vmax= V 1,3 W where W is the width at half height of the pulse amplitude distribution peaking at V (this allows more than 99,7 % of the pulse amplitude distribution to pass through the window) f) Background: Background intensity
30、 at the peak position is obtained using a linear regression between two background measurements before and after the fluorescence peak wavelength: 23,62 The recommended positions (2 min, 2 max) are: 2 min, max = 2 4 Wwhere 2is the peak position Wis the peak width at half height of the peak g) Counti
31、ng time: 100 s for both peak and background measurements; total counting time 300 s 5 Sample preparation 5.1 Granulometry Powders shall be fine enough to obtain a good homogeneous pellet without a binder. The particle size distribution, determined in accordance with EN 725-5, shall be between 10 m a
32、nd 2 m with an equivalent diameter corresponding to 50 % of the grain size. NOTE Grinding the sample may increase the oxygen content of the powder. 5.2 Test piece preparation 5.2.1 Where comparatively large (10 g) samples are available, pour the powder into a die (e.g. 40 mm in diameter) and compact
33、 it. The powder may be placed in an aluminium cup before pressing if required. 5.2.2 For smaller samples (2 g), press the powder on to a backing plate made of cellulose or boric acid powder. The aluminium cup may again be used if required. 5.2.3 Prepare two samples for each determination. NOTE In mo
34、st quantitative analysis, sample thickness is considered as infinite. If critical thickness is the thickness that would yield 99,9 % of the maximum intensity, calculation shows that critical thickness increased from 2,9 m to 3,35 m when oxygen concentration in AIN increases from 0,5 % to 10 %. 6 Cal
35、ibration 6.1 Preparation of standards Prepare calibration standards from mixtures of aluminium nitride powder in accordance with 5.1 and alumina powder with a specific surface area of about 6 m2/g according to EN ISO 18757 and an equivalent diameter corresponding to 50 % of the distribution, normall
36、y 1 m or less. Mix the powders for at least 10 min in an agate mortar and pestle, and vibrate the mixture for 1 min. 6.2 Calibration curves Establish curves which record the oxygen (K) net intensity with the oxygen mass fraction in the different calibration mixtures. EN 725-4:2006 (E) 7 As aluminium
37、 nitride powders used in calibration mixtures are not oxygen free, an addition method shall be used in order to determine the total oxygen concentration. In this method, a known amount of oxygen, O, is added to the sample. Fluorescence intensities I1and I2, before and after addition, are used to ext
38、rapolate to the unknown concentration. If linearity is assumed: 211IIIOO=The addition method is limited to fairly low concentrations, usually less than 1 %. Thereby, the use of an aluminium nitride powder with oxygen concentration 1 % is recommended for calibration purposes. The shape of the calibra
39、tion curve depends on the oxygen concentration range, but within a range of 0 % to 5 %, a linear regression is likely to be convenient. 6.3 Recalibration Recalibration is needed in order to check long term instrumental drift. An aluminium nitride sintered pellet with a flat polished surface can be u
40、sed to shift the calibration curve. The oxygen content of this reference standard should not be lower than 3 % in order to obtain a good signal intensity level. Another solution, which is more time consuming, consists in the determination of a new calibration curve. 6.4 Sensitivity limit of detectio
41、n EXAMPLE Sensitivity (S): slope of the linear part of the calibration curve expected sensitivity S = 80 cps/% (counts per second per %). Limit of detection for a confidence level of 3 (LD3) StnLD/33=where n is the background intensity at peak position (40 cps); t is the measuring time (100 s); LD3i
42、s the oxygen content (240 10-6(240 ppm). 7 Repeatability This procedure has been applied to nine pellets of the same fine aluminium nitride powder, with the analytical results given in Table 1. EN 725-4:2006 (E) 8 Table 1 Example of repeatability for nine pellets from the same aluminium nitride powd
43、er Pellet No Oxygen concentration (wt%) 1 1,039 2 1,037 3 1,070 4 1,044 5 1,086 6 1,069 7 1,062 8 1,049 9 1,05x (mean value) 1,057 (standard deviation) 0,016 x = (relative standard deviation) 1,55 NOTE 1 The relative error on oxygen concentration determination is %,*522t* with 95 % confidence level
44、(p = 0,05, n-1 = 8), the Student factor = 2,306; * two pellets are pressed; one measurement is made on each pellet. NOTE 2 The results obtained are not sufficient for establishing reproducibility values. 8 Test report The report shall be in accordance with the reporting provisions of EN ISO/IEC 1702
45、5, and shall include at least following information: a) name and address of the testing establishment; b) date of test; c) on each page, a unique report identification and page number; d) customer name and address; e) reference to this European Standard, i.e. determined in accordance with EN 725-4;
46、f) authorising signature; g) any deviation from the method described, with appropriate validation demonstration, to be acceptable for the parties involved; h) equipment used; EN 725-4:2006 (E) 9 i) calibration procedures; j) description of the powder (e.g. material type, manufacturer code, batch or
47、code number); k) relevant test parameters; l) results of individual determinations, mean results and standard deviations; m) comments on the test or test results. EN 725-4:2006 (E) 10 Bibliography 1 EN ISO 12677, Chemical analysis of refractory products by XRF Fused cast bead method (ISO 12677:2003)
