1、DRAFT FOR DEVELOPMENT DD CEN/TS 1159-4:2004 Advanced technical ceramics Ceramic composites Thermophysical properties Part 4: Determination of thermal conductivity ICS 81.060.30 DD CEN/TS 1159-4:2004 This Draft for Development was published under the authority of the Standards Policy and Strategy Com
2、mittee on 18 August 2004 BSI 18 August 2004 ISBN 0 580 44303 5 National foreword This Draft for Development is the official English language version of CEN/TS 1159-4:2004. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publicat
3、ions and is of a provisional nature because it is considered that further experience is required in its application before it is converted to a European and hence British Standard. It should be applied on this provisional basis, so that information and experience of its practical application may be
4、obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European Standard. A review of this publication will be initiated 2 years after its publication by the European o
5、rganization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI
6、 Committee will decide whether to support the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee RPI/13, Advanced technical ceramics, at British Standards House, 389
7、Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which imple
8、ment international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. Summary of pages Thi
9、s document comprises a front cover, an inside front cover, the CEN/TS title page, pages 2 to 15 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsTECHNICALSPECIFICATION SPCIFICA
10、TIONTECHNIQUE TECHNISCHESPEZIFIKATION CEN/TS11594 July2004 ICS81.060.30 Englishversion AdvancedtechnicalceramicsCeramiccomposites ThermophysicalpropertiesPart4:Determinationofthermal conductivity ThisTechnicalSpecification(CEN/TS)wasapprovedbyCENon13July2001forprovisionalapplication. Theperiodofvali
11、dityofthisCEN/TSislimitedinitiallytothreeyears.AftertwoyearsthemembersofCENwillberequested tosubmittheir comments,particularlyonthequestionwhethertheCEN/TScanbeconvertedintoaEuropeanStandard. CENmembersarerequiredtoannouncetheexistenceofthisCEN/TSinthesamewayasforanENandtomaketheCEN/TSavailable prom
12、ptlyatnationallevelinanappropriateform.Itispermissibletokeepconflictingnationalstandardsinforce(inparall eltotheCEN/TS) untilthefinaldecisionaboutthepossibleconversionoftheCEN/TSintoanENisreached. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,F
13、rance, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeSta
14、ssart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.CEN/TS11594:2004:ECEN/TS 1159-4:2004 (E) 2 Contents Page Foreword. 3 1 Scope 5 2 Normative references . 5 3 Terms and definitions. 5 4 Significance and use 6 5 Principle . 6 6 A
15、pparatus 8 7 Test specimens dimensions 9 8 Test specimens preparation 10 9 Number of test specimens . 11 10 Test procedure 11 11 Test validity . 14 12 Results . 14 13 Test report . 15 CEN/TS 1159-4:2004 (E) 3 Foreword This document CEN/TS 1159-4:2004 has been prepared by Technical Committee CEN/TC 1
16、84 “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 January 2005, and conflicting national standards shall be withdrawn at th
17、e latest by January 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Icel
18、and, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 1159 Advanced technical ceramics Ceramic composites. Thermophysical properties consists of four parts: Part 1: Determination of ther
19、mal expansion; Part 2: Determination of thermal diffusivity; Part 3: Determination of specific heat capacity; Part 4: Determination of thermal conductivity. Part 4 is a Technical Specification. CEN/TS 1159-4:2004 (E) 4 Introduction Statement on patent use Attention is drawn to the fact that complian
20、ce with this document may involve the use of a patented process, which is the “Process for determining the thermal conductivity of a material at high temperature and conductimeter for implementation of this process“, given in this document. CEN takes no position concerning the evidence, validity and
21、 scope of this patent right. The holder of the patent has provided a statement concerning use of the patented process. The holder of this patent right has assured CEN that he is willing to negotiate licences under reasonable and non- discriminatory terms and conditions with the applicants throughout
22、 the world. In this respect, the statement of the holder of this patent right is registered with CEN. Further information may be obtained from: European Aeronautic Defence and Space Company EADS France S.A.S. Mr Jean-Marc THOMAS Avenue du Gnral Niox BP 11 33 165 Saint-Mdard-en-Jalles cedex - FRANCE
23、Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights other than those identified above. CEN shall not be held responsible for identifying any or all such patent rights. CEN/TS 1159-4:2004 (E) 5 1 Scope This document describes a method f
24、or the determination of the thermal conductivity of ceramic matrix composites with continuous fibre reinforcement. This method applies to all ceramic matrix composites with a fibre reinforcement, unidirectional (1D), bidirectional (2D), and tridirectional (xD, with 2 x 3) as defined in ENV 13233, su
25、bmitted to a heat flux along one principal axis of anisotropy. The experimental conditions are such that the material behaves in an homogeneous manner for each of its axis of anisotropy and that the heat transfer occurs only by thermal conduction. The method is applicable to materials which are phys
26、ically and chemically stable during the measurement. Contrary to other methods of direct measurement which permit only to determine a value of the thermal conductivity averaged over an interval of temperature, the method described in this document, based on an adequate exploitation of the temperatur
27、e record, allows to determine with a good accuracy the thermal conductivity at a defined temperature. This is more interesting since the variation of the thermal conductivity with the temperature is non-linear, which is generally the case for CMCs. NOTE It is also possible to calculate the conductiv
28、ity of CMCs by an indirect method using the following equation: = a p b C pwhere is the thermal conductivity; a is the thermal diffusivity; p bis the bulk density; C pis the specific heat capacity. 2 Normative references The following referenced documents are indispensable for the application of thi
29、s document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ENV 13233, Advanced technical ceramics Ceramic composites Notations and symbols ISO 3611, Micrometer callipers for external meas
30、urements 3 Terms and definitions For the purposes of this document, the terms and definition and symbols given in ENV 13233 and the following apply. CEN/TS 1159-4:2004 (E) 6 3.1 heat flow, quantity of heat transferred per unit time 3.2 density of heat flow, heat flow per unit area 3.3 representative
31、 volume element minimum volume that is representative of the material considered 3.4 temperature of the hot face, T htemperature of the face designated the hot face in Figures 1 and 2 3.5 temperature of the cold face, T ctemperature of the face designated the cold face in Figures 1 and 2 3.6 tempera
32、ture of the internal wall, T inftemperature of the wall designated the internal wall in Figure 4 3.7 temperature gradient, T/h ratio of the temperature difference T = T h T cbetween the two parallel faces of the test specimen to the distance between the two faces, h 3.8 thermal conductivity, ratio o
33、f the density of heat flow to the temperature gradient 4 Significance and use Methods of measurement of the thermal conductivity (either standardised or not) are in the majority dedicated to the characterisation of insulating materials with values lower than or equal to 1 W.m -1 .K -1 . Indeed, a pr
34、incipal feature of all direct methods of determination of the thermal conductivity consists in creating a thermal gradient in the test specimen, which explains why such methods are successful when used with insulating materials. Ceramic matrix composites however, have values of thermal conductivity
35、at low and moderate temperatures in the range of 15 W.m -1 .K -1to 100 W.m -1 .K -1 . These values decrease with increasing temperature, but still remain relatively high. This behaviour would require the use of very thick test specimens, in order to achieve a sufficient thermal gradient, a requireme
36、nt which cannot usually be met. In this case an indirect method such as measurement of the thermal diffusivity, should be used. 5 Principle The variation of the thermal conductivity of the CMCs with temperature is generally non linear over the range of temperature currently considered. CEN/TS 1159-4
37、:2004 (E) 7 This document describes a method for the determination of the thermal conductivity within an increment of temperature assuming that the thermal conductivity is linear within this increment. This increment depends upon the material tested. In the first instance it will be set at a value o
38、f 100 C. The front face (hot face) of a test specimen is exposed to a uniformly distributed temperature T husing a heating plate. After the system reaches equilibrium, the temperature T cof the rear face (cold face) is measured as well as the heat flow at this face (see Figures 1 and 2). In order to
39、 achieve good conditions of thermal insulation of the lateral faces, it is recommended to use a “guarded test specimen“ as depicted in Figures 1 and 2. Key 1 Tool to secure good contact between the test specimen, 6 Heating plate the heat-flow measurement system and the heating plate 7 Area of heat t
40、ransfer 2 Heat-flow measurement system 8 Guarded test specimen 3 Thermocouples 9 Lateral insulation 4 Lateral insulation 10 Cold face, T c5 Hot face, T hFigure 1 General arrangement of the apparatus for measurement of the temperature on the two faces by thermocouples CEN/TS 1159-4:2004 (E) 8 Key 1 T
41、ool to secure good contact between the test specimen, 7 Heating plate the heat-flow measurement system and the heating plate 8 Temperature measurement with 2 Temperature measurement with a pyrometer a pyrometer 3 Heat-flow measurement system 9 Guarded test specimen 4 Area or heat transfer 10 Lateral
42、 insulation 5 Lateral insulation 11 Cold face, T c6 Hot face, T hFigure 2 General arrangement of the apparatus for measurement of the temperature on the two faces by pyrometry Considering the accuracy of the temperature measurements on the hot and the cold faces, a minimum difference of 100 C betwee
43、n these two faces is recommended. 6 Apparatus All the components described below shall be made from materials which will not react with the test specimen: heating source: heating plate with a flat surface, with which a temperature uniformity to within 5 C over the range of temperatures measured shal
44、l be achievable; gas-tight cooled chamber allowing to maintain an inert or vacuum atmosphere; temperature measuring equipment, with thermocouples, preferably in accordance with EN 60584- 1 and EN 60584-2, or with an optical pyrometer. Pyrometers or thermocouples which are not covered by EN 60584-1 a
45、nd EN 60584-2 shall be appropriately calibrated; heat flow meter if used; NOTE If a heat flow meter is not used, Clause 10.4 applies. CEN/TS 1159-4:2004 (E) 9 tool to secure a good contact between the heat-flow measurement system, the test specimen and the heating plate. This tool shall not generate
46、 a thermal gradient that could alter the determination of the thermal conductivity; devices to measure the dimensions of the area of heat transfer, and the thickness of the test specimen which shall be accurate to 0,1 mm. Micrometers shall be in accordance with ISO 3611. Since the apparatus construc
47、ted for the determination of the thermal conductivity is composed of a complicated assembly of different components, it shall be validated after any change of one or more of these components, by a test following the procedure indicated in Clause 10, using a test specimen made from a material of know
48、n properties. 7 Test specimens dimensions The thickness of the specimen shall be adjusted as function of the conductivity of the material in order to obtain a temperature difference T between the two faces of the test specimen equal to or higher than 100 C for the increment of temperature chosen. The area of heat transfer shall be at least 10 times the surface of the representative volume element. NOTE Test specimens as depicted in Figure 3 are commonly used. CEN/TS 1159-4:2004 (E) 10 Dimension in millimetres Key 1
