1、BRITISH STANDARD BS EN 821-1:1995 Advanced technical ceramics Monolithicceramics Thermo-physical properties Part 1: Determination of thermal expansion The European Standard EN821-1:1995 has the status of a British StandardBSEN821-1:1995 This British Standard, having been prepared under the direction
2、of the Sector Board for Materials and Chemicals, was published under the authority ofthe Standards Board and comesinto effect on 15September1995 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference RPI/13 Draft for comment 92/45078 DC ISBN 0 580 24106 8 C
3、ommittees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee RPI/13, Advanced technical ceramics, upon which the following bodies were represented: AEA Technology Aluminium Federation British Ceramic Research Ltd. British Industrial Ce
4、ramic Manufacturers Association Department of Trade and Industry (National Physical Laboratory) Flat Glass Manufacturers Association GAMBICA (BEAMA Ltd.) Institute of Refractories Engineers Ministry of Defence Refractories Association of Great Britain Society of British Aerospace Companies Limited U
5、niversity of Manchester Amendments issued since publication Amd. No. Date CommentsBSEN821-1:1995 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN821-1 3 List of references Inside back coverBSEN821-1:1995 ii BSI 11-1999 National foreword
6、 This British Standard has been prepared by Technical Committee RPI/13, and is the English language version of EN821-1:1995 Advanced technical ceramics Monolithic ceramics Thermo-physical properties Part 1: Determination of thermal expansion, published by the European Committee for Standardization (
7、CEN). EN821-1 was produced as a result of international discussions in which the UK took an active part. EN821 consists of three Parts: Part 1: Determination of thermal expansion; Part 2: Determination of thermal diffusivity; Part 3: Determination of specific heat capacity(ENV). A British Standard d
8、oes not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding Britis
9、h Standard EN 45001 BS 7501:1989 General criteria for the operation of testing laboratories ENV 1006 DDENV:1994 Advanced technical ceramics Methods of testing monolithic ceramics Guidance on the sampling and selection of test pieces BS 4937 International thermocouple reference tables HD 446.1S1 Part
10、 1:1973 Platinum-10% rhodium/platinum thermocouples. TypeS Part 2:1973 Platinum-13% rhodium/platinum thermocouples. TypeR Part 3:1973 Iron/copper-nickel thermocouples. TypeJ Part 4:1973 Nickel-chromium/nickel-aluminium thermocouples. TypeK Part 5:1974 Copper/copper-nickel thermocouples. TypeT Part 6
11、:1974 Nickel-chromium/copper-nickel thermocouples. TypeE Part 7:1974 Platinum-30% rhodium/platinum-6% rhodium thermocouples. TypeB Part 8:1986 Nickel-chromium-silicon/nickel-silicon (nicrosil/nisil) thermocouples including composition. TypeN Summary of pages This document comprises a front cover, an
12、 inside front cover, pagesi andii, theEN title page, pages2to14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPE
13、NNE EUROPISCHE NORM EN 821-1 January 1995 ICS 81.060.10;81.060.20 Descriptors: Ceramics, thermodynamic properties, tests, determination, thermal expansion English version Advanced technical ceramics Monolithic ceramics Thermo-physical properties Part 1: Determination of thermal expansion Cramiques t
14、echniques avances Cramiques monolithiques Proprits thermo-physiques Partie1: Dtermination de la dilatation thermique Hochleistungskeramik Monolithische Keramik Thermophysikalische Eigenschaften Teil 1: Bestimmung der thermischen Lngennderung This European Standard was approved by CEN on1995-01-04. C
15、EN members are bound 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 ap
16、plication 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 translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat ha
17、s the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland UnitedKingdom. CEN European Committee for Standardi
18、zation Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 Copyright reserved to CEN members Ref. No.821-1:1995EEN821-1:1995 BSI 11-1999 2 Foreword This European Standard has been prepared by the Technical Committee CEN/TC184, A
19、dvanced 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 byJuly1995, and conflicting national standards shall be withdrawn at the latest by
20、July1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, UnitedKingd
21、om. EN 821 consists of three Parts: Part 1: Determination of thermal expansion; Part 2: Determination of thermal diffusivity; Part 3: Determination of specific heat capacity (ENV). Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3 4 Principle 3 5 Apparatus 3 6 Test pieces 6
22、 7 Procedure 8 8 Calculation of results 9 9 Reporting of results 9 10 Test report 9 Annex A (normative) Calibration of apparatus (direct-measuring instruments) 11 Annex B (normative) Calibration of apparatus (differential type) 12 Annex C (informative) Thermal expansion reference data 12 Annex D (in
23、formative) Bibliography 14 Figure 1 Schematic diagrams of apparatus arrangements 4 Figure 2 Suitable constructions of test piece holders in silica and alumina 5 Figure 3 Silica ball test piece support and carrier 7 Figure 4 Example of arrangement of differential thermocouples to monitor temperature
24、distribution in the test piece, where%T 1 ,%T 2are differential temperatures 7 Figure 5 Test pieces witha) rounded ends for use with flat end plate and push rod surfaces andb) flat square ends for use with rounded end plate and push rod surfaces in a conventional horizontal dilatometer 8 Table 1 Req
25、uirements for accuracy levelsA andB 3 Table 2 Thermal expansion reference data 13EN821-1:1995 BSI 11-1999 3 1 Scope This Part ofEN 821 describes the method for the determination of the linear thermal expansion characteristics of advanced monolithic technical ceramics up to a maximum temperature of15
26、00C(see5.2) and to a specified level of accuracyA orB as defined inTable 1. The method describes general principles of construction, calibration and operation of suitable apparatus. Specific details, including test piece dimensions, depend on the design of the apparatus. Methods of calibration are g
27、iven inAnnex A andAnnex B. Thermal expansion reference data are given inAnnex C. 2 Normative references This European Standard incorporates by dated or undated references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publicati
28、ons are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 45001, Genera
29、l criteria for the operation of testing laboratories. ENV 1006, Advanced technical ceramics Methods of testing monolithic ceramics Guidance on the sampling and selection of test pieces. HD 446.1S1, Thermocouples Part1: Reference tables. ISO 3611, Micrometer callipers for external measurement. ISO 69
30、06, Vernier callipers reading to0,02mm. 3 Definitions For the purposes of this Part ofEN821, the following definitions apply. 3.1 linear thermal expansion the proportional extension which occurs when a material is heated 3.2 linear thermal expansion coefficient the proportional extension which occur
31、s when a material is heated over a temperature interval of1K at temperatureT 3.3 mean linear thermal expansion coefficient the average value of the thermal expansion coefficient over a temperature rangeT 1toT 2 4 Principle A test piece is heated and subsequently cooled, either at a specified uniform
32、 rate or using defined temperature increments. Its change of length and its temperature is measured continuously during the heating and cooling. The percentage expansion or contraction over the required temperature range is calculated and the results presented both as a mean linear thermal expansion
33、 coefficient over chosen temperature ranges, and as a graph of thermal expansion against temperature. 5 Apparatus 5.1 General. The apparatus shall conform to the specification given below and be capable of calibration according to the procedures given either inAnnex A for direct measurement orAnnex
34、B for differential measurement. Any suitable proprietary apparatus may be used and suitable designs are shown inFigure 1. Table 1 Requirements for accuracy levelsA andB Test method requirement Measurement accuracy required A B Required accuracy of result over100K temperature interval 0,1 10 6 K 1 0,
35、5 10 6 K 1 Temperature variation along test piece during test 2K 5K Deviation from smooth temperature ramp or hold 1K 2K Expansion measurement device sensitivity and repeatability (%of specimen length) 0,001% 0,005% Sensitivity of recording of thermocouple temperatures 0,1K 0,5KEN821-1:1995 4 BSI 11
36、-1999 5.2 Construction materials. For measurements from below ambient temperature to1000 C, transparent fused silica or fused quartz shall be used for construction of the test piece holder. For measurements from ambient temperature to temperatures above1000 C, an alumina ceramic of at least99,8%Al 2
37、 O 3shall be used for construction of the test piece holder. NOTEThe use of fused silica or fused quartz at temperatures above800 C can lead to structural changes or crystallization, and thus to changes in the thermal expansion coefficient of the apparatus. Calibration of the apparatus (seeAnnex A a
38、nd Annex B) should be carried out frequently, and if there is any sign of discontinuities in the expansion curves resulting from phase transitions of cristobalite(150 C to250 C) or quartz(573 C), the apparatus should be replaced. The push rod for transmitting the displacement of the test piece to th
39、e measuring device shall be of the same material as the test piece holder. 5.3 Test piece holder. Some possible constructions of the test piece holder are shown inFigure 2. For use with round-ended test pieces (seeclause6) the outer sleeve shall have an end-plate with a surface ground flat to within
40、104m. The normal to the surface of the end-plate shall be visually square to the measurement axis. For use with flat-ended test pieces (seeclause6) the outer sleeve shall have an end-plate which is rounded to a radius of curvature of between1mm and20mm. The push-rod end in contact with the test piec
41、e shall have similar shape to the test piece holder end-plate. For test piece holders constructed from fused silica tube or rod(see5.3) the end-plate shall be rigidly fixed to the outer sleeve by flame fusing at a point remote from the end-plate surface. Alternatively, for outer sleeves constructed
42、from fused silica rod, the end-plate may be prepared by machining from solid material. Examples of constructions are shown inFigure 2a). NOTEArrangement a) may also be inclined at an angle to the horizontal or may be vertical(seeFigure 2). Figure 1 Schematic diagrams of apparatus arrangementsEN821-1
43、:1995 BSI 11-1999 5 For test piece holders constructed from alumina(see5.2) rod, the end-plate may be prepared by machining from solid material. If constructed from alumina tube, fusion is not possible. For vertical measuring apparatus, the outer sleeve shall be fixed to a flat plate using refractor
44、y cement outside the joint as shown inFigure 2b). For non-vertical measuring apparatus in which the sleeve end is free-standing, a closed end alumina tube shall be used, and the end-plate machined to fit inside the tube end as shown inFigure 2c). The assembly shall then be fixed in position with a s
45、uitable refractory cement, and then fired to a temperature greater than1400 C under an axial load. NOTEThe firing under load minimizes the risk of movement of the assembly during use. Some movement may still occur during initial use. Thermal cycling should be continued until the net movement over a
46、thermal cycle to the highest temperature at which the apparatus is to be used is less than14m. Alternatively, an end-plate may be shaped to fit in tangential slots in the tube. If this approach is adopted, the components shall be designed to fit together with no possibility of relative movement in u
47、se,e.g. by wedging into position. Figure 2 Suitable constructions of test piece holders in silica and aluminaEN821-1:1995 6 BSI 11-1999 5.4 Test piece mounting. For vertical measuring apparatus, the test pieces shall be free-standing and mechanically stable on the end-plate (see5.3). For measuring a
48、pparatus which is horizontal or inclined to the horizontal, the sideways movement or twist of the test piece shall be restricted, without any restriction of axial movement, by a suitable arrangement. NOTEThis may be done, for example, by a) using a vee-block cut to fit into the test piece holder; or
49、 b) by using test pieces of such dimensions that either a neat sliding fit (but see clause6) or support on two edges is obtained; or c) using an arrangement of supporting silica glass or alumina balls, as shown inFigure 3. Where the apparatus is designed for differential measurements, two test pieces shall be suitably mounted parallel to each other, contacting on a single end-plate. 5.5 Thermocouples. The thermocouples shall be typeR,S orK, in accordance with HD446
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