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1、 Reference number ISO 22007-2:2008(E) ISO 2008 INTERNATIONAL STANDARD ISO 22007-2 First edition 2008-12-15 Plastics Determination of thermal conductivity and thermal diffusivity Part 2: Transient plane heat source (hot disc) method Plastiques Dtermination de la conductivit thermique et de la diffusi
2、vit thermique Partie 2: Mthode de la source plane transitoire (disque chaud) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license fr
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6、t the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
7、either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reserved Copyright Internat
8、ional Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 22007-2:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv Int
9、roduction v 1 Scope 1 2 Normative references1 3 Terms and definitions .2 4 Principle3 5 Apparatus .3 6 Test specimens5 6.1 Bulk specimens5 6.2 Anisotropic bulk specimens.6 6.3 Slab specimens6 6.4 Thin-film specimens6 7 Procedure .7 8 Calculation of thermal properties 9 8.1 Bulk specimens9 8.2 Anisot
10、ropic bulk specimens.12 8.3 Slab specimens13 8.4 Thin-film specimens14 9 Calibration and verification 14 9.1 Calibration of apparatus .14 9.2 Verification of apparatus.14 10 Precision and bias.15 11 Test report16 Bibliography17 Copyright International Organization for Standardization Provided by IHS
11、 under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 22007-2:2008(E) iv ISO 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide fed
12、eration of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that comm
13、ittee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accorda
14、nce with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires
15、 approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 22007-2 was prepared by Technical
16、 Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical- chemical properties. ISO 22007 consists of the following parts, under the general title Plastics Determination of thermal conductivity and thermal diffusivity: Part 1: General principles Part 2: Transient plane heat source (hot disc) metho
17、d Part 3: Temperature wave analysis method Part 4: Laser flash method Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS
18、-,-,- ISO 22007-2:2008(E) ISO 2008 All rights reserved v Introduction A significant increase in the development and application of new and improved materials for broad ranges of physical, chemical, biological and medical applications has necessitated better performance data from methods of measureme
19、nt of thermal-transport properties. The introduction of alternative methods that are relatively simple, fast and of good precision would be of great benefit to the scientific and engineering communities 1. A number of measurement techniques described as contact transient methods have been developed
20、and several have been commercialized. These are being widely used and are suitable for testing many types of material. In some cases, they can be used to measure several properties separately or simultaneously 2,3. A further advantage of some of these methods is that it has become possible to measur
21、e the true bulk properties of a material. This feature stems from the possibility of eliminating the influence of the thermal contact resistance (see 8.1.1) that is present at the interface between the probe and the specimen surfaces 1,3,4,5,6. Copyright International Organization for Standardizatio
22、n Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910
23、770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 22007-2:2008(E) ISO 2008 All rights reserved 1 Plastics Determination of thermal conductivity and thermal diffusivity Part 2: Transient plane heat source (h
24、ot disc) method 1 Scope 1.1 This part of ISO 22007 specifies a method for the determination of the thermal conductivity and thermal diffusivity, and hence the specific heat capacity per unit volume, of plastics. The experimental arrangement can be designed to match different specimen sizes. Measurem
25、ents can be made in gaseous and vacuum environments at a range of temperatures and pressures. 1.2 This method is suitable for testing homogeneous and isotropic materials, as well as anisotropic materials with a uniaxial structure. In general, the method is suitable for materials having values of the
26、rmal conductivity, , in the approximate range 0,01 Wm1K1 500 Wm1K1 and values of thermal diffusivity, , in the range 5 108 m2s1 u u 104 m2s1, and for temperatures, T, in the approximate range 50 K T 1 000 K. NOTE The specific heat capacity per unit volume, C, can be obtained by dividing the thermal
27、conductivity, , by the thermal diffusivity, , i.e. C = /, and is in the approximate range 0,2 MJm3K1 C 5 MJm3K1. It is also referred to as the volumetric heat capacity. 1.3 The thermal-transport properties of liquids can also be determined, provided care is taken to minimize thermal convection. 2 No
28、rmative 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 amendments) applies. ISO 472, Plastics Vocabulary I
29、SO 22007-1, Plastics Determination of thermal conductivity and thermal diffusivity Part 1: General principles Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networ
30、king permitted without license from IHS -,-,- ISO 22007-2:2008(E) 2 ISO 2008 All rights reserved 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 472 and ISO 22007-1 and the following apply. 3.1 penetration depth ppen measure of how far into the speci
31、men, in the direction of heat flow, a heat wave has travelled NOTE 1 For this method, the penetration depth is given by pentot pt = where ttot is the total measurement time for the transient recording; is the thermal diffusivity of the specimen material; is a constant dependent on the sensitivity of
32、 the temperature recordings. NOTE 2 It is expressed in metres (m). 3.2 probing depth pprob measure of how far into the specimen, in the direction of heat flow, a heat wave has travelled during the time window used for calculation NOTE 1 The probing depth is given by probmax pt = where tmax is the ma
33、ximum time of the time window used for calculating the thermal-transport properties. NOTE 2 It is expressed in metres (m). NOTE 3 A typical value in hot-disc measurements is = 2, which is assumed throughout this document. 3.3 sensitivity coefficient q coefficient defined by the equation ( ) q T t q
34、q = where q is the thermal conductivity, , the thermal diffusivity, , or the volumetric specific heat capacity, C; T(t) is the mean temperature increase of the probe NOTE 1 Different sensitivity coefficients are defined for thermal conductivity, thermal diffusivity and specific heat per unit volume
35、8. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 22007-2:2008(E) ISO 2008 All rights reserved 3 NOTE 2 To
36、define the time window that is used to determine both the thermal conductivity and diffusivity from one single experiment, the theory of sensitivity coefficients is used. Through this theory, which deals with a large number of experiments and considers the constants, q, as variables, it has been est
37、ablished that 0,30 u tmax/r2 u 1,0 where r is the mean radius of the outermost spiral of the probe. Assuming = 2, this expression can be rewritten as 1,1r u pprob u 2,0r 4 Principle A specimen containing an embedded hot-disc probe of negligible heat capacity is allowed to equilibrate at a given temp
38、erature. A heat pulse in the form of a stepwise function is produced by an electrical current through the probe to generate a dynamic temperature field within the specimen. The increase in the temperature of the probe is measured as a function of time. The probe operates as a temperature sensor unif
39、ied with a heat source (i.e. a self-heated sensor). The response is then analysed in accordance with the model developed for the specific probe and the assumed boundary conditions. 5 Apparatus 5.1 A schematic diagram of the apparatus is shown in Figure 1. 5 67 8 1 2 3 4 Key 1 specimen with probe 5 b
40、ridge circuit 2 chamber 6 voltmeter 3 vacuum pump 7 voltage source 4 thermostat 8 personal computer Figure 1 Basic layout of the apparatus 5.2 A typical hot-disc probe is shown in Figure 2. Convenient probes can be designed with diameters from 4 mm to 100 mm, depending on the specimen size and the t
41、hermal-transport properties of the material to be tested. The probe is constructed as a bifilar spiral etched out of a (10 2) m thick metal foil and covered on both sides by thin (from 7 m to 100 m) insulating film. It is recommended that nickel or molybdenum be used as the heater/temperature-sensin
42、g metal foil due to their relatively high temperature coefficient of electrical resistivity and stability over a wide temperature range. It is recommended that polyimide, mica, aluminum nitride or aluminum oxide be used as the insulating film, depending on the ultimate temperature of use. The arms o
43、f the bifilar spiral forming an essentially circular probe shall have a width of (0,20 0,03) mm for probes with an overall diameter of 15 mm or less and a width of (0,35 0,05) mm for probes of larger diameter. The distance between the edges of the arms shall be the same as the width of the arms. Cop
44、yright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 04:15:08 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 22007-2:2008(E) 4 ISO 2008 All rights reserved Figure 2 Probe w
45、ith bifilar spiral as heating/sensing element (Sensor diameters, D, from 4 mm to 100 mm can be used, depending on available specimen size) 5.3 An electrical bridge shall be used to record the transient increase in resistance of the probe. Through the bridge, which is initially balanced, the successi
46、ve increases in resistance of the probe shall be followed by recording the imbalance of the bridge with a sensitive voltmeter (see Figure 3). With this arrangement, the probe is placed in series with a resistor which shall be designed in such a way that its resistance is kept strictly constant throu
47、ghout the transient. These two components are combined with a precision potentiometer, the resistance of which shall be about 100 times larger than the sum of the resistances of the probe and the series resistor. The bridge shall be connected to a power supply which can supply 20 V and a current of
48、up to 1 A. The digital voltmeter by which the difference voltages are recorded shall have a resolution corresponding to 6,5 digits at an integration time of 1 power line cycle. The resistance of the series resistor, RS, shall be close to the initial resistance of the probe with its leads, R0 + RL, in order to keep the power