1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58powders Part 4: Determination of oxygen content in aluminium nitride by XRF analysisThe European St
2、andard EN 725-4:2006 has the status of a British StandardICS 81.060.30Advanced technical ceramics Methods of test for ceramic BRITISH STANDARDBS EN 725-4:2006BS EN 725-4:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI
3、 2006ISBN 0 580 49711 9Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK imple
4、mentation of EN 725-4:2006. It supersedes DD ENV 725-4:1994 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics. A list of organizations represented on RPI/13 can be obtained on request to its secretary.This publication
5、does not purport to include all the necessary provisions of a EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 725-4April 2006ICS 81.060.30 Supersedes ENV 725-4:1994 English VersionAdvanced technical ceramics - Methods of test for ceramicpowders - Part 4: Determination of oxygen content in aluminiu
6、mnitride by XRF analysisCramiques techniques avances - Mthodes dessai pourpoudres cramiques - Partie 4: Dtermination de la teneuren oxygne du nitrure daluminium par spectromtrie defluorescence XRFHochleistungskeramik - Prfverfahren fr keramischePulver - Teil 4: Bestimmung der Sauerstoffgehaltes inAl
7、uminiumnitrid-Pulvern mittels Rntgenfluoreszensanalyse(RFA)This European Standard was approved by CEN on 13 March 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 a
8、ny 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
9、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,
10、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 NORMUNGManagement Centre
11、: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 725-4:2006: E2 Contents Page Foreword 3 1 Scope .5 2 Normative references .5 3 Principle.5 4 Apparatus and experimental conditions .5 4.1 Appa
12、ratus 5 4.2 Experimental conditions.5 5 Sample preparation.6 5.1 Granulometry 6 5.2 Test piece preparation6 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 725-4:200
13、63 Foreword This European Standard (EN 725-4:2006) has been prepared by Technical Committee CEN/TC 184 “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 end
14、orsement, at the latest by October 2006, and conflicting national standards shall be withdrawn at the 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 th
15、e normative references; - modification of the test piece preparation requirements; - modification of 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
16、 of impurities in alumina Part 2: Determination of impurities in barium titanate Part 3: Determination 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 distribu
17、tion Part 6: Determination of specific surface area withdrawn Part 7: Determination of absolute density 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 na
18、tural sintering Part 12: Chemical analysis of zirconia Parts 6 and 7 of the series were superseded in 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 Eur
19、opean Standard: Austria, Belgium, Cyprus, Czech Republic, EN 725-4:20064 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 Unit
20、ed Kingdom. EN 725-4:20065 1 Scope This European Standard specifies a method for the determination 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
21、. For dated references, only the edition cited applies. For undated references, the latest 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 1
22、7025, General requirements for the competence of testing and calibration laboratories (ISO/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
23、Principle The sample is compacted to obtain a pellet, and the net intensity of the oxygen Kcharacteristic (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 de
24、termined from this net intensity and by reference to previously defined calibration graphs; 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 alumi
25、na powder. 4 Apparatus and experimental conditions 4.1 Apparatus Sequential X-ray fluorescence 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 th
26、e apparatus, with an example of good practice being as follows: a) Mode: vacuum b) Excitation: 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 725-4:20066 e) D
27、etection: detector type: gas flow proportional counter Ar-CH4or He-CO2pulse height selection: 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
28、amplitude distribution to pass through the window) f) Background: Background intensity 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
29、4 Wwhere 2is the peak position Wis the peak width at half height of the peak g) Counting 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 parti
30、cle size distribution, determined in accordance with EN 725-5, shall be between 10 m and 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)
31、samples are available, pour the powder into a die (e.g. 40 mm in diameter) and compact 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 a
32、gain be used if required. 5.2.3 Prepare two samples for each determination. NOTE In most 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 fro
33、m 2,9 m to 3,35 m when oxygen concentration in AIN increases from 0,5 % to 10 %. 6 Calibration 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 I
34、SO 18757 and an equivalent diameter corresponding to 50 % of the distribution, normally 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
35、 mass fraction in the different calibration mixtures. EN 725-4:20067 As aluminium 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 samp
36、le. Fluorescence intensities I1and I2, before and after addition, are used to extrapolate 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 co
37、ncentration 1 % is recommended for calibration purposes. The shape of the calibration 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
38、drift. An aluminium nitride sintered pellet with a flat polished surface can be used 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 i
39、n the determination of a new calibration curve. 6.4 Sensitivity limit of detection 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 back
40、ground intensity at peak position (40 cps); t is the measuring time (100 s); LD3is 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 725-4:20068 Table 1 Ex
41、ample of repeatability for nine pellets from the same aluminium nitride powder 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 o
42、n oxygen concentration determination is %,*522t* with 95 % confidence level (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 re
43、port shall be in accordance with the reporting provisions of EN ISO/IEC 17025, 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) refere
44、nce to this European Standard, i.e. determined in accordance with EN 725-4; 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 725-4:20069 i) calibration procedures; j) desc
45、ription of the powder (e.g. material type, manufacturer code, batch or 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 725-4:200610 Bibliography 1 EN ISO 12677, Chemical analysis of
46、refractory products by XRF Fused cast bead method (ISO 12677:2003) EN 725-4:2006blankBS EN BSI389 Chiswick High RoadLondonW4 4AL725-4:2006BSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe
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