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1、BRITISH STANDARD BS EN 12923-1:2006 Advanced technical ceramics Monolithic ceramics Part 1: General practice for undertaking corrosion tests The European Standard EN 12923-1:2006 has the status of a British Standard ICS 81.060.99 ? Licensed Copy: London South Bank University, London South Bank Unive
2、rsity, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS EN 12923-1:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 March 2007 BSI 2007 ISBN 978 0 580 50457 0 National foreword This British Standard was published by BS
3、I. It is the UK implementation of EN 12923-1:2006. It supersedes DD ENV 12923-1:1998 which is withdrawn.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 s
4、ecretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed C
5、opy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12923-1 December 2006 ICS 81.060.99Supersedes ENV 12923-1:1997 English Version Advanced technical ceramics - Monolithic
6、 ceramics - Part 1: General practice for undertaking corrosion tests Cramiques techniques avances - Cramiques monolithiques - Partie 1: Pratique gnrale destine aux essais de corrosion Hochleistungskeramik - Monolithische Keramik - Teil 1: Allgemeines zur Durchfhrung von Korrosionsprfungen This Europ
7、ean Standard was approved by CEN on 25 November 2006. CEN 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 c
8、oncerning such national standards 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 translation under the responsibility of a CEN member into its
9、own language and notified to the Central Secretariat has the same status as the official versions. 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, Luxem
10、bourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CENAll rig
11、hts of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12923-1:2006: E Licensed Copy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 2 Contents Page Fore
12、word4 1 Scope.5 2 Normative references 5 3 Terms and definitions6 4 Significance and use .6 5 Assessment of corrosive attack.7 5.1 Introduction 7 5.2 Method A: Depth of penetration .7 5.3 Method B: Mass change8 5.4 Method C: Change of test piece size .9 5.5 Method D: Strength change9 5.6 Method E: C
13、hange in surface roughness9 5.7 Method F: Change in hardness 9 6 Apparatus for laboratory corrosion testing 10 6.1 Container for corroding medium10 6.2 Heating device10 6.3 Thermocouple 10 6.4 Chemical balance.10 6.5 Oven 10 6.6 Dye penetrant equipment10 6.7 Travelling microscope or optical microsco
14、pe 11 6.8 Micrometer11 6.9 Vernier callipers.11 6.10 Surface roughness measuring equipment11 6.11 Flexural strength test facility11 6.12 Hardness measurement equipment.11 7 Test pieces11 7.1 General requirements11 7.2 Specific requirements11 7.3 Number of test pieces12 8 Test procedure .12 8.1 Safet
15、y considerations12 8.2 Corrosion test.12 8.3 Procedure .12 9 Expression of results.14 9.1 Calculation of mass change (Method B)14 9.2 Change of component or test piece size (Method C).14 9.3 Calculation of flexural strength (Method D)15 10 Test report 15 Annex A (informative) Appropriate container a
16、nd specimen holder materials for corrosion testing17 A.1 Mineral acids, excluding hydrofluoric acid.17 A.2 Hydrofluoric acid (HF) .17 A.3 Aqueous-based alkaline solutions.17 A.4 Molten metal alloys17 A.5 Molten slags .18 Licensed Copy: London South Bank University, London South Bank University, Mon
17、Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 3 A.6 Corrosive gases .18 Bibliography 19 Licensed Copy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 4 Foreword This docum
18、ent (EN 12923-1:2006) 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 endorsement, at the latest by Ju
19、ne 2007, and conflicting national standards shall be withdrawn at the latest by June 2007. This document supersedes ENV 12923-1:1997. EN 12923 Advanced technical ceramics Monolithic ceramics consists of two parts: Part 1: General practice for undertaking corrosion tests Part 2: Oxidation test At the
20、 time of publication of this edition of Part 1, Part 2 was a European Prestandard. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Esto
21、nia, 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. Licensed Copy: London South Bank University, London South Bank University,
22、 Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 5 1 Scope This part of EN 12923 specifies guidelines to be employed when undertaking corrosion tests on advanced technical ceramics. The mechanisms of chemical attack on advanced ceramics are widely varied and depend
23、 on the chemical and phase composition and the phase morphology of the material, as well as the corrosive conditions imposed. For any particular engineering application it is usually necessary to model expected conditions of use in order to obtain quantitative data on the ability to withstand the pr
24、oposed end-use conditions. This European Standard is not restricted to specific material types, nor does it prescribe particular test conditions or a test duration. The actual testing requirements might be very specific, for example, in order to investigate the suitability of a range of materials fo
25、r a given application in which certain specified conditions occur. This European Standard provides recommended methods for undertaking the assessment of the effect of corrosion and provides guidance on practical issues related to undertaking the tests. 2 Normative references The following referenced
26、 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. EN 623-1, Advanced technical ceramics Monolithic ceramics General and tex
27、tural properties Part 1: Determination of the presence of defects by dye penetration EN 623-4, Advanced technical ceramics Monolithic ceramics General and textural properties Part 4: Determination of surface roughness EN 843-1, Advanced technical ceramics Mechanical properties of monolithic ceramics
28、 at room temperature Part 1: Determination of flexural strength EN 843-4, Advanced technical ceramics Mechanical properties monolithic ceramics at room temperature Part 4: Vickers, Knoop and Rockwell superficial hardness ENV 1006, Advanced technical ceramics Monolithic ceramics Guidance on the selec
29、tion of test pieces for the evaluation of properties EN 60584-1, Thermocouples Part 1: Reference tables EN 60584-2, Thermocouples Part 2: Tolerances EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 3611, Micrometer callipers f
30、or external measurement ISO 6906, Vernier callipers reading to 0,02 mm Licensed Copy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 6 3 Terms and definitions For the purposes of this document, the follow
31、ing terms and definitions apply. 3.1 corrosion process of degradation induced by chemical attack by a surrounding medium on a ceramic body 3.2 oxidation process of reaction of a ceramic material with oxygen in the surrounding atmosphere, including any internal reactions as a result of the presence o
32、f open porosity or of diffusion of ions to or from the ceramic surface 4 Significance and use Advanced technical ceramic materials are widely regarded as being generally resistant to corrosion, and many types find applications in highly corrosive conditions where other materials are not viable. Howe
33、ver, this is not always the case, and the selection of the most appropriate material requires some form of assessment to provide assurance that it has adequate resistance to the conditions to which it is to be exposed. The rate of chemical attack is determined by: i) the chemical nature, phase compo
34、sition, phase distribution and degree of continuous porosity in the material; ii) the temperature, pressure, composition, concentration and flow rate of the corroding medium and whether these are constant or vary with time; iii) the mechanical forces applied to the material in terms of internal stre
35、ss condition and the degree of surface abrasion or wear due to contact with other surfaces, the presence of abrasive particles or the dissolving effect of the corroding medium itself; iv) the period for which the test is performed, because it cannot be assumed that the rate of attack is constant wit
36、h time. Adjusting test conditions to accelerate the corrosion process and extrapolating corrosion rates to times longer than that of the test should not be done. These factors need to be carefully selected, clearly specified and reported in any corrosion test. The undertaking of corrosion tests is n
37、ormally for two principal purposes: a. to simulate performance in an application, which will require careful consideration of all factors pertaining to the conditions under which corrosion is occurring, and which will require these to be modelled in the test environment; b. to provide a comparative
38、measure of performance of a range of materials under defined corrosion conditions. This European Standard provides a basis for undertaking corrosion tests and details the criteria which might be considered for determining whether attack has taken place and has significant consequences for subsequent
39、 use of a material. Since corrosion is dependent on a wide range of parameters, this European Standard does not prescribe particular environments or durations of attack, but provides guidance on the key factors that need to be considered or specified in undertaking tests and gives a general framewor
40、k for conducting tests in a meaningful manner. Licensed Copy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 7 5 Assessment of corrosive attack 5.1 Introduction Chemical attack is manifest in a number of
41、ways: a. change of dry mass; b. change of section thickness; c. change of colour; d. penetration of corrodent into the material rendering the surface open porous; e. development of surface skins of altered composition; f. development of a surface skin of reaction product; g. change of surface finish
42、; h. change in strength; i. change of hardness or wear resistance. Furthermore, attack might not be linear with time, notably if the diffusion path for corroding species increases with increasing corrosion. Table 1 summarizes the areas of validity of using these criteria for various types of corrosi
43、ve attack. These criteria apply to passive conditions of corrosion, i.e. not when the component is under an externally applied stress. NOTE 1 Other situations might exist in which it is desirable to record changes in other properties, for example, thermal conductivity and thermal shock resistance, e
44、ither whilst immersed in the corroding medium, or after extraction from it. Such methods are not specifically included in this European Standard and might require special equipment not covered by this European Standard. Change of colour might be subjective. NOTE 2 This European Standard does not lay
45、 down any recommended methods for determining the quantity of test piece species dissolved in a corrodent (Method G). Reference should be made to standard analytical practices. Care should be taken in selection of the container material, corrosion of which may influence the results of such an analys
46、is. 5.2 Method A: Depth of penetration 5.2.1 For materials subjected to corrodents which result in grain boundary attack and penetration of the corrodent, the depth of penetration might be strongly influenced by the microstructural nature of the original test piece surface. Some as-fired surfaces mi
47、ght have better resistance to penetration than bulk microstructures exposed by machining test pieces. When possible, testing should avoid as- fired surfaces unless the testing is specifically to evaluate the performance of such surfaces. 5.2.2 The depth of penetration might be variable if the micros
48、tructure is inhomogeneous. The greatest depth of penetration is to be recorded. 5.2.3 In materials with substantial pre-existing closed porosity, it might be difficult to determine the true depth of penetration if there is no major change in the appearance of the microstructure. Reliance should be p
49、laced on the use of penetrant dyes in accordance with EN 623-1. Licensed Copy: London South Bank University, London South Bank University, Mon Apr 02 00:22:30 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 12923-1:2006 (E) 8 Table 1 Appropriateness of methods of assessing corrosive attack Assessment method Aqueous based corrosion Corrosion by melts Corrosion by gases and vapours A. Penetration Appropriate Might be Appropriate in some appropriate cases B. Change of ma
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