1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58powders Part 11: Determination of densification on natural sinteringThe European Standard EN 725-11
2、:2006 has the status of a British StandardICS 81.060.99Advanced technical ceramics Methods of test for ceramic BRITISH STANDARDBS EN 725-11:2006BS EN 725-11:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 BSI 2006ISBN 0
3、580 49225 7Amendments 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 implementation of
4、 EN 725-11:2006. It supersedes DD ENV 725-11:1994 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics.A list of organizations represented on RPI/13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 does not pu
5、rport to include all the necessary provisions of a EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 725-11June 2006ICS 81.060.99 Supersedes ENV 725-11:1993 English VersionAdvanced technical ceramics - Methods of test for ceramicpowders - Part 11: Determination of densification on naturalsinteringCr
6、amiques techniques avances - Mthodes dessai pourpoudres cramiques - Partie 11: Dtermination de ladensification lors du frittage naturelHochleistungskeramik - Prfverfahren fr keramischePulver -Teil 11: Bestimmung der Verdichtungsverhaltensbei natrlichem SinterbrandThis European Standard was approved
7、by CEN on 25 May 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 any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards
8、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 translationunder the responsibility of a CEN member into its own language and notified to the Cen
9、tral 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, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pola
10、nd, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any
11、means reservedworldwide for CEN national Members.Ref. No. EN 725-11:2006: EEN 725-11:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Principle4 4 Terms, symbols and units 5 5 Apparatus .5 6 Test pieces .6 7 Heating conditions.6 8 Procedure .6 9 Expression of results 6 10 Test
12、 report 7 EN 725-11:2006 (E) 3 Foreword This document (EN 725-11:2006) 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 iden
13、tical text or by endorsement, at the latest by December 2006, and conflicting national standards shall be withdrawn at the latest by December 2006. This document supersedes ENV 725-11:1993. EN 725 Advanced technical ceramics Methods of test for ceramic powders was prepared in Parts as follows: Part
14、1: Determination of impurities in alumina Part 2: Determination of impurities in barium titanate Part 3: Determination of oxygen content of non-oxides by thermal extraction Part 4: Determination of oxygen content in aluminium nitride by XRF analysis Part 5 Determination of particle size distribution
15、 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 natu
16、ral 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 Europe
17、an Standard: 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, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 725
18、-11:2006 (E) 4 1 Scope This Part of EN 725 describes a method for determining the densification of ceramic powders on natural sintering, without the application of any external pressure. The method is applicable to pure oxides, mixtures of oxides and solid solutions. Inorganic sintering additives ma
19、y be used where their presence is reported. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any ame
20、ndments) applies. EN 623-2:1993, Advanced technical ceramics Monolithic ceramics General and textural properties Part 2: Determination of density and porosity EN 725-10, Advanced technical ceramics Methods of test for ceramic powders Part 10: Determination of compaction properties EN ISO/IEC 17025,
21、General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 3611, Micrometer callipers for external measurement 3 Principle Measurements are made of the mass, dimensions and density of a compacted piece of ceramic powder, before and after sintering throug
22、h thermal treatment. The results depend on the maximum temperature and the density after compaction, and are expressed as a function of these two main parameters. EN 725-11:2006 (E) 5 4 Terms, symbols and units Terms, symbols and units are given in Table 1. Table 1 Terms, symbols and units Term Symb
23、ol Unit Mass before sintering Makg Mass after sintering M kg Volume before sintering Vam Volume after sintering V m Apparent density before sintering dakg/m Apparent density after sintering d kg/m Theoretical density dthkg/m Largest dimension of sample before sintering Lam Largest dimension of sampl
24、e after sintering L m Relative mass variation at the end of the sintering aMM- Relative volume variation at the end of the sintering aVV- Relative density variation at the end of the sintering add- Relative length variation (shrinkage) at the end of the sintering aLL- Sintering temperature T K These
25、 characteristics are linked by the following relations: aaaVMd = aaaMMMMM )( =aaaddddd )( =VMd = aaaVVVVV )( =aaaLLLLL )( =5 Apparatus 5.1 Furnace, having a hot zone large enough to accommodate the required size and number of test pieces, and capable of maintaining the test temperature (T) so that t
26、he maximum temperature variation in the hot zone is 10 K. The furnace shall allow a constant heating rate, which can be controlled to within 2 K/h. The furnace heating elements, thermal insulation and kiln furniture shall be selected to be chemically compatible with the test pieces, avoiding both su
27、rface reaction and generation of vapour pressure. The kiln furniture used to support the test pieces should be a sintered piece of the test material. EN 725-11:2006 (E) 6 5.2 Balance, capable of weighing at least 10 g with an accuracy of 0,005 g. 5.3 Micrometer, conforming to ISO 3611, or other suit
28、able measuring device for measuring the dimensions of the compacts with an accuracy of 0,001 mm. 6 Test pieces Prepare the test pieces in accordance with EN 725-10, making at least three pieces at each of the compacting pressures selected from those given in EN 725-10. 7 Heating conditions 7.1 Selec
29、tion of test temperatures Measurements shall be made over a range of test temperatures. The lower limit of the range is defined as the temperature at which the relative density (d/dth) is approximately 0,9. The higher limit is defined as either a) the temperature at which the onset of de-densificati
30、on resulting from grain growth is observed; or b) the temperature at which a substantial loss of mass is recorded. The temperature range shall be at least 100 K. NOTE Preliminary tests may be used to define the temperature range, in which case the thermal cycle specified in 7.2 should be used. 7.2 T
31、hermal cycle The rates of heating shall be as follows: a) from room temperature to 600 C at 60 K/h; b) from 600 C to the test temperature at 180 K/h. The test temperature shall be maintained for 1 h. Cooling is normally achieved by switching off the heating in the furnace, but may be controlled when
32、 required, in which case the rates of cooling shall be reported. 8 Procedure 8.1 Measure the mass Ma, and the dimensions of each test piece. Designate the largest dimension as La. Calculate the density dafrom the mass and dimensions in accordance with EN 725-10. 8.2 Carry out the heat treatment on t
33、he test pieces in accordance with 7.2. 8.3 Re-measure the mass (M) and the dimensions of each test piece. Designate the largest dimension L. Calculate the density (d) from the mass and dimensions in accordance with EN 623-2:1993, Method 2. 9 Expression of results Report the results of sintering in t
34、hree expressions as follows (see clause 4). EN 725-11:2006 (E) 7 a) Mass variation aaMMM )( ; b) Sintering shrinkage aaLLL )( ; c) Relative density thdd. Present the results in a table, with the three results from three test pieces for each combination of compacting pressure and sintering temperatur
35、e. Plot a graph to show as a set of curves the variation of the density and relative density as a function of the sintering temperature for each compaction pressure. 10 Test report The test report shall be in accordance with the reporting provisions of EN ISO/IEC 17025 and shall include at least the
36、 following information: a) name and address of the testing establishment; b) date of the test; c) on each page, a unique report identification and page number; d) customer name and address; e) reference to this standard, i.e. determined in accordance with EN 725-11; f) authorising signature; g) any
37、deviation from the method described, with appropriate validation, i.e. demonstrated to be acceptable to the parties involved; h) description of the powder (e.g. material type, manufacturer code, batch or code number, presence of inorganic or organic additives); i) theoretical density dthused in the
38、calculations; j) any additional information on the thermal cycle (see 7.2); k) results for mass variation and sintering shrinkage; l) results for relative density as a function of compaction pressure and of sintering (test) temperature; m) any comments about the test or test results. BS EN BSI389 Ch
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