1、BRITISH STANDARDBS EN 12923-1:2006Advanced technical ceramics Monolithic ceramics Part 1: General practice for undertaking corrosion testsThe European Standard EN 12923-1:2006 has the status of a British StandardICS 81.060.99g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g
2、48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIBS EN 12923-1:2006This British Standard was published under the authority of the Sta
3、ndards Policy and Strategy Committee on 30 March 2007 BSI 2007ISBN 978 0 580 50457 0National forewordThis British Standard was published by BSI. 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 It supersedes DD ENV 12923-1:1998 which is withdrawn.The UK participation in its preparation was entrusted
4、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 purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance w
5、ith a British Standard cannot confer immunity from legal obligations. Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12923-1December 2006ICS 81.060.9
6、9 Supersedes ENV 12923-1:1997 English VersionAdvanced technical ceramics - Monolithic ceramics - Part 1:General practice for undertaking corrosion testsCramiques techniques avances - Cramiquesmonolithiques - Partie 1: Pratique gnrale destine auxessais de corrosionHochleistungskeramik - Monolithische
7、 Keramik - Teil 1:Allgemeines zur Durchfhrung von KorrosionsprfungenThis European 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 EuropeanStandard the status of a national standa
8、rd without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards 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 langu
9、age made by translationunder the responsibility of a CEN member into its own language and notified to the Central 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,Germa
10、ny, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManag
11、ement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12923-1:2006: ELicensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 2 Co
12、ntents Page Foreword4 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 change
13、9 5.6 Method E: Change 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
14、 optical microscope 11 6.8 Micrometer11 6.9 Vernier callipers .11 6.10 Surface roughness measuring equipment11 6.11 Flexural strength test facility 11 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 proc
15、edure .12 8.1 Safety 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) App
16、ropriate container and 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: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00
17、 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 3 A.6 Corrosive gases .18 Bibliography 19 Licensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 4 Foreword This document (EN 12923-1:2006) has been prepared by Technical Committee CEN/TC 184
18、 “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 June 2007, and conflicting national standards shall be withdrawn at the lat
19、est 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 time of publication of this edition of Part 1, Part 2 was a European Pre
20、standard. 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, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
21、Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 5 1 Scope This part of EN 12923 spec
22、ifies 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 on the chemical and phase composition and the phase morphology of the material, as well as the corrosive conditions imp
23、osed. 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 proposed end-use conditions. This European Standard is not restricted to specific material types, nor does it prescribe pa
24、rticular 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 for a given application in which certain specified conditions occur. This European Standard provides recommended methods f
25、or 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 documents are indispensable for the application of this document. For dated references, only the edition cited applies.
26、 For undated references, the latest edition of the referenced document (including any amendments) applies. EN 623-1, Advanced technical ceramics Monolithic ceramics General and textural properties Part 1: Determination of the presence of defects by dye penetration EN 623-4, Advanced technical cerami
27、cs Monolithic ceramics General and textural properties Part 4: Determination of surface roughness EN 843-1, Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 1: Determination of flexural strength EN 843-4, Advanced technical ceramics Mechanical propert
28、ies monolithic ceramics at room temperature Part 4: Vickers, Knoop and Rockwell superficial hardness ENV 1006, Advanced technical ceramics Monolithic ceramics Guidance on the selection of test pieces for the evaluation of properties EN 60584-1, Thermocouples Part 1: Reference tables EN 60584-2, Ther
29、mocouples 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 for external measurement ISO 6906, Vernier callipers reading to 0,02 mm Licensed Copy: Wang Bin, na, Fri May 25 07:39:07
30、GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 6 3 Terms and definitions For the purposes of this document, the following 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 rea
31、ction of a ceramic material with oxygen in the surrounding atmosphere, including any internal reactions as a result of the presence of 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 general
32、ly resistant to corrosion, and many types find applications in highly corrosive conditions where other materials are not viable. However, 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 resista
33、nce to the conditions to which it is to be exposed. The rate of chemical attack is determined by: i) the chemical nature, phase composition, phase distribution and degree of continuous porosity in the material; ii) the temperature, pressure, composition, concentration and flow rate of the corroding
34、medium and whether these are constant or vary with time; iii) the mechanical forces applied to the material in terms of internal stress 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 corrodin
35、g medium itself; iv) the period for which the test is performed, because it cannot be assumed that the rate of attack is constant with 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
36、 factors need to be carefully selected, clearly specified and reported in any corrosion test. The undertaking of corrosion tests is normally for two principal purposes: a. to simulate performance in an application, which will require careful consideration of all factors pertaining to the conditions
37、under which corrosion is occurring, and which will require these to be modelled in the test environment; b. to provide a comparative measure of performance of a range of materials under defined corrosion conditions. This European Standard provides a basis for undertaking corrosion tests and details
38、the criteria which might be considered for determining whether attack has taken place and has significant consequences for subsequent 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 attac
39、k, but provides guidance on the key factors that need to be considered or specified in undertaking tests and gives a general framework for conducting tests in a meaningful manner. Licensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 7 5 Asses
40、sment of corrosive attack 5.1 Introduction Chemical attack is manifest in a number of 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 composit
41、ion; f. development of a surface skin of reaction product; g. change of surface finish; 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
42、 summarizes the areas of validity of using these criteria for various types of corrosive 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
43、in other properties, for example, thermal conductivity and thermal shock resistance, either 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 Stan
44、dard. Change of colour might be subjective. NOTE 2 This European Standard does not lay 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
45、the container material, corrosion of which may influence the results of such an analysis. 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 th
46、e microstructural nature of the original test piece surface. Some as-fired surfaces might 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 perform
47、ance of such surfaces. 5.2.2 The depth of penetration might be variable if the microstructure 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 t
48、here is no major change in the appearance of the microstructure. Reliance should be placed on the use of penetrant dyes in accordance with EN 623-1. Licensed Copy: Wang Bin, na, Fri May 25 07:39:07 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 12923-1:2006 (E) 8 Table 1 Appropriateness of methods of
49、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 mass Appropriate, but Inappropriate Appropriate if non- sometimes inadequate slagging C. Change of cross- Not always appropriate Appropriate Appropriate section when change is small D. Change of strength Appropriate Might be Appropriate if non- appropriate if adherent slagging; might be material is removed appropriate if adherent materi
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