EN ISO 28706-3-2018 en Vitreous and porcelain enamels - Determination of resistance to chemical corrosion - Part 3 Determination of resistance to chemical corrosion by alkaline liq.pdf

1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Vitreous and porcelain enamels - Determination of resistance to chemical corrosionPart 3: Determination of resistance to chemical corrosion by alkaline liquids using a hexagonal vessel or a tetragonal glass bottleBS EN

2、ISO 287063:2018National forewordThis British Standard is the UK implementation of EN ISO 287063:2018. It is identical to ISO 287063:2017. It supersedes BS EN ISO 287063:2011, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee STI/36, Vitreous enamel coati

3、ngs.A list of organizations represented on this committee 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. The British Standards Institution 2018 Published by BSI St

4、andards Limited 2018ISBN 978 0 580 88390 3ICS 25.220.50Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2018.Amendments/corrigenda issued since publicat

5、ionDate Text affectedBRITISH STANDARDBS EN ISO 287063:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 287063February 2018ICS 25.220.50 Supersedes EN ISO 287063:2011EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCENCENELEC Management Centre

6、: Avenue Marnix 17, B1000 Brussels 2018 CEN Ref. No. EN ISO 287063:2018: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersVitreous and porcelain enamels Determination of resistance to chemical corrosion Part 3: Determination of resistance to chemica

7、l corrosion by alkaline liquids using a hexagonal vessel or a tetragonal glass bottle (ISO 287063:2017)maux vitrifis - Dtermination de la rsistance la corrosion chimique - Partie 3: Dtermination de la rsistance la corrosion chimique par des liquides alcalins dans un rcipient hexagonal ou une bouteil

8、le en verre ttragonale (ISO 28706-3:2017)Emails und Emaillierungen Bestimmung der Bestndigkeit gegen chemische Korrosion Teil 3: Bestimmung der Bestndigkeit gegen chemische Korrosion durch alkalische Flssigkeiten unter Verwendung eines Gertes mit hexagonalem Gef oder einer tetragonalen Glasflasche (

9、ISO 28706-3:2017)This European Standard was approved by CEN on 1 December 2017.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. Uptodate lists and bibli

10、ographical references concerning such national standards may be obtained on application to the CENCENELEC Management Centre 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 responsib

11、ility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic

12、 of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionEN ISO 287063:2018 (E)European forewordThis

13、 document (EN ISO 287063:2018) has been prepared by Technical Committee ISO/TC 107 “Metallic and other inorganic coatings” in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of metals and alloys” the s

14、ecretariat 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 August 2018, and conflicting national standards shall be withdrawn at the latest by August 2018.Attention is draw

15、n to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document supersedes EN ISO 287063:2011.According to the CENCENELEC Internal Regulations, the national standards or

16、ganisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembour

17、g, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 287063:2017 has been approved by CEN as EN ISO 287063:2018 without any modification.2BS EN ISO 287063:2018ISO 287063:2017F

18、oreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Reagents 26 Apparatus and materials 26.2.2 Magnetic stirrer with heating . 87 Test specimens 98 Procedure. 98.1 General . 98.2 Hexagonal vessel . 98.3 Tetragonal glass bottle 109 Expression of result

19、s .1010 Standard detergent solution test 1010.1 General 1010.2 Test solution . 1110.3 Test temperature 1110.4 Duration of the test 1110.5 Test report 1111 Other test solutions and/or conditions .1211.1 General 1211.2 Test solution . 1211.3 Test temperature 1211.4 Duration of the test 1211.5 Test rep

20、ort 12Bibliography .13 ISO 2017 All rights reserved iiiContents PageBS EN ISO 287063:2018ISO 287063:2017ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normal

21、ly 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 committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the

22、 work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the d

23、ifferent approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document

24、 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/pa

25、tents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information abo

26、ut ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings.This second edition cancels and replace

27、s the first edition (ISO 287063:2008), which has been technically revised.A list of all parts in the ISO 28706 series can be found on the ISO website.iv ISO 2017 All rights reservedBS EN ISO 287063:2018ISO 287063:2017IntroductionCorrosion of vitreous and porcelain enamels by aqueous solutions is a d

28、issolution process. The main component of the enamel, SiO2, forms a three-dimensional silica network. After hydrolysis, it decomposes and forms silicic acid or silicates. These are released into the attacking medium. Other components, mainly metal oxides, are hydrolyzed as well and form the correspo

29、nding hydrated metal ions or hydroxides. All corrosion products are more or less soluble in the attacking medium. The whole process results in a loss in mass per unit area.For some aqueous solutions, the attack on the enamel proceeds linearly during the corrosion time; for other aqueous solutions, t

30、he attack on the enamel proceeds in a logarithmic manner during the corrosion time. Only for the first series of solutions can a scientifically exact rate of loss in mass per unit area (g/m2h) be calculated as well as a corrosion rate (mm/year).The most important parameters influencing aqueous corro

31、sion of the enamel are the enamel quality, the temperature and the pH-value. Inhibition effects resulting from the limited solubility of silica can also contribute. The following list describes different types of enamel attack for different corrosion conditions.a) In aqueous alkali solutions like 0,

32、1 mol/l NaOH (see ISO 287064:2016, Clause 9), the silica network of the enamel is considerably attacked at 80 C. Silicates and most of the other hydrolyzed components are soluble in the alkali. Attack proceeds linearly during regular test times. Therefore, test results are expressed in terms of a ra

33、te of loss in mass per unit area (mass loss per unit area and time) and a corrosion rate (millimetres per year).b) At room temperature, in weak aqueous acids like citric acid (see ISO 287061:2008, Clause 9) or also in stronger acids like sulfuric acid (see ISO 287061:2008, Clause 10), there is only

34、minor attack on the silica network of the enamel. Other constituents are leached to some extent from the surface. Highly resistant enamels will show no visual change after exposure. On less resistant enamels, some staining or surface roughening will occur.c) In boiling aqueous acids (see ISO 287062)

35、, the silica network of the enamel is being attacked, and silica as well as the other enamel components are released into solution. However, the solubility of silica in acids is low. Soon, the attacking solutions will become saturated with dissolved silica and will then only leach the surface. The a

36、cid attack is inhibited and the rate of corrosion drops markedly.NOTE The glass test equipment also releases silica by acid attack and contributes to the inhibition of the corrosion.Inhibition is effectively prevented in vapour phase tests. The condensate formed on the test specimen is free of any d

37、issolved enamel constituents.Examples of enamel corrosion proceeding in a logarithmic manner see 1) and linearly see 2) are:1) Boiling citric acid (see ISO 287062:2017, Clause 11) and boiling 30 % sulfuric acid (see ISO 287062:2017, Clause 12)Since only minute amounts of these acids are found in the

38、ir vapours, the test is restricted to the liquid phase. The attack is influenced by inhibition effects, and corrosion depends on the time of exposure. Therefore, test results are expressed in terms of loss in mass per unit area; no rate of loss in mass per unit area is calculated.2) Boiling 20 % hyd

39、rochloric acid (see ISO 287062:2017, Clause 13)Since this is an azeotropic boiling acid, its concentration in the liquid and the vapour phase are identical, and liquid phase testing need not be performed. Vigorous boiling supplies an uninhibited condensate, and the attack proceeds linearly with time

40、 of exposure. Therefore, test results are only expressed in terms of rate of loss in mass per unit area (mass loss per unit area and time) and the corrosion rate (millimetres per year). ISO 2017 All rights reserved vBS EN ISO 287063:2018ISO 287063:2017d) At high temperatures, with tests in the liqui

41、d phase under autoclave conditions (see ISO 287065), aqueous acid attack is severe. To avoid inhibition, the test time is restricted to 24 h and the ratio of attacking acid to attacked enamel surface is chosen so that it is comparatively high (similar to that in a chemical reaction vessel). In addit

42、ion, only low-silica water is used for the preparation of test solutions. Under these conditions, attack will proceed linearly with time of exposure. Therefore, test results with 20 % hydrochloric acid (see ISO 287065:2010, Clause 8), artificial test solutions (see ISO 287065:2010, Clause 10) or pro

43、cess fluids (see ISO 287065:2010, Clause 11) are also expressed in terms of a rate of loss in mass per unit area (loss in mass per unit area and time).e) In boiling water (see ISO 287062:2017, Clause 14), the silica network is fairly stable. The enamel surface is leached and silica is dissolved only

44、 to a small extent. This type of attack is clearly represented by the vapour phase attack. In the liquid phase, some inhibition can be observed with highly resistant enamels. However, if the enamel being tested is weak, leached alkali from the enamel can raise pH-values to alkaline levels, thus incr

45、easing the attack by the liquid phase. Both liquid and vapour phase testing can give valuable information.f) Since the attack may or may not be linear, the results are expressed only in terms of loss in mass per unit area, and the test time should be indicated.g) For standard detergent solution (see

46、 Clause 10), it will not be certain whether the linear part of the corrosion curve will be reached during testing for 24 h or 168 h. Calculation of the corrosion rate is therefore not included in the test report.h) For other acids (see ISO 287062:2017, Clause 16) and other alkaline solutions (see Cl

47、ause 11 and ISO 287064:2016, Clause 11), it will also not be known if a linear corrosion rate will be reached during the test period. Calculation of the corrosion rate is therefore not included in the test reports of those parts of the ISO 28706 series.For vitreous enamels fired at temperatures belo

48、w 700 C, the test parameters (media, temperatures and times) of this document are not appropriate. For such enamels, for example, aluminium enamels, other media, temperatures and/or times should be used. This can be done following the procedures described in the clauses for “other test solutions” in

49、 ISO 287061, ISO 287062, this document (ISO 287063) and ISO 287064.vi ISO 2017 All rights reservedBS EN ISO 287063:2018Vitreous and porcelain enamels - Determination of resistance to chemical corrosion Part 3: Determination of resistance to chemical corrosion by alkaline liquids using a hexagonal vessel or a tetragonal glass bottle1 ScopeThis document describes a test method for the determination of the resistance of vitreous and porcelain enamelled articles to attack by alkaline liquids