DIN EN ISO 28706-4-2016 Vitreous and porcelain enamels - Determination of resistance to chemical corrosion - Part 4 Determination of resistance to chemical corrosion by alkaline li.pdf

1、July 2016 English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 25.220.50!%XLD“2534133www.din.deDIN

2、 EN ISO 28706-4Vitreous and porcelain enamels Determination of resistance to chemical corrosion Part 4: Determination of resistance to chemical corrosion by alkaline liquids using a cylindrical vessel (ISO 28706-4:2016);English version EN ISO 28706-4:2016,English translation of DIN EN ISO 28706-4:20

3、16-07Emails und Emaillierungen Bestimmung der Bestndigkeit gegen chemische Korrosion Teil 4: Bestimmung der Bestndigkeit gegen chemische Korrosion durch alkalische Flssigkeiten unter Verwendung eines Gertes mit zylindrischem Gef (ISO 28706-4:2016);Englische Fassung EN ISO 28706-4:2016,Englische bers

4、etzung von DIN EN ISO 28706-4:2016-07maux vitrifis Dtermination de la rsistance la corrosion chimique Partie 4: Dtermination de la rsistance la corrosion chimique par des liquides alcalins dans un rcipient cylindrique (ISO 28706-4:2016);Version anglaise EN ISO 28706-4:2016,Traduction anglaise de DIN

5、 EN ISO 28706-4:2016-07SupersedesDIN EN ISO 28706-4:2011-08www.beuth.deDocument comprises 22 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.07.16 DIN EN ISO 28706-4:2016-07 2 A comma is used as the decimal marker. National for

6、eword This document (EN ISO 28706-4:2016) 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” (Secretariat: BSI, United Kingdom). The responsible German body involved

7、in its preparation was DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-01-63 AA Prfung von Emails und Emaillierungen. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 48 ISO 868 IS

8、O 1042 ISO 3696 ISO 28764 DIN ISO 48 DIN EN ISO 868 DIN EN ISO 1042 DIN ISO 3696 DIN EN ISO 28764 Amendments This standard differs from DIN EN ISO 28706-4:2011-08 as follows: a) a WARNING has been included; b) a hot 1,0 mol/l sodium hydroxide test has been included (Clause 10). Previous editions DIN

9、 51156: 1967-02 DIN ISO 2734: 1982-11, 1984-06, 1999-02 DIN ISO 2745: 1982-11, 1999-09 DIN EN 14483-4: 2004-09 DIN EN ISO 28706-4: 2011-08 DIN EN ISO 28706-4:2016-07 3 National Annex NA (informative) Bibliography DIN EN ISO 868, Plastics and ebonite Determination of indentation hardness by means of

10、a durometer (Shore hardness) DIN EN ISO 1042, Laboratory glassware One-mark volumetric flasks DIN EN ISO 28764, Vitreous and porcelain enamels Production of specimens for testing enamels on sheet steel, sheet aluminium and cast iron DIN ISO 48, Rubber, vulcanized or thermoplastic Determination of ha

11、rdness (hardness between 10 IRHD and 100 IRHD) DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN EN ISO 28706-4:2016-07 4 This page is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 28706-4 January 2016 ICS 25.220.50 Supersedes EN ISO

12、28706-4:2011English Version Vitreous and porcelain enamels - Determination of resistance to chemical corrosion - Part 4: Determination of resistance to chemical corrosion by alkaline liquids using a cylindrical vessel (ISO 28706-4:2016) maux vitrifis - Dtermination de la rsistance la corrosion chimi

13、que - Partie 4: Dtermination de la rsistance la corrosion chimique par des liquides alcalins dans un rcipient cylindrique(ISO 28706-4:2016) Emails und Emaillierungen - Bestimmung der Bestndigkeit gegen chemische Korrosion - Teil 4: Bestimmung der Bestndigkeit gegen chemische Korrosion durch alkalisc

14、he Flssigkeiten unter Verwendung eines Gertes mit zylindrischem Gef (ISO 28706-4:2016) This European Standard was approved by CEN on 7 November 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status

15、of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, Germa

16、n). A version in any other language made by translation under the responsibility 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,

17、 Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and Unite

18、d Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN I

19、SO 28706-4:2016 EEuropean foreword 3Introduction . 51 Scope . 72 Normative references 73 Principle 74 Reagents 85 Apparatus and material 86 Test specimens 137 Procedure. 138 Expression of results 148.1 Total loss in mass per unit area 148.2 Corrosion rate 149 Hot 0,1 mol/l sodium hydroxide test . 15

20、9.1 General . 159.2 Test solution, c(NaOH) = 0,1 mol/l 159.3 Test temperature . 159.4 Duration of the test . 159.5 Test report . 1510 Hot 1,0 mol/l sodium hydroxide test 1610.1 General 1610.2 Test solution, c(NaOH) = 1,0 mol/l .1610.3 Test temperature 1610.4 Duration of the test 1610.5 Test report 1

21、611 Other test solutions 1711.1 General 1711.2 Test solution .1711.3 Test temperature 1711.4 Duration of the test 1711.5 Test report 17Bibliography .18Contents PageForeword .4DIN EN ISO 28706-4:2016-07 EN ISO 28706-4:2016 (E) 2 European foreword This document (EN ISO 28706-4:2016) has been prepared

22、by Technical Committee ISO/TC 107 “Metallic and other inorganic coatings” in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publicati

23、on of an identical text or by endorsement, at the latest by July 2016, and conflicting national standards shall be withdrawn at the latest by July 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not

24、be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 28706-4:2011. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgari

25、a, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turke

26、y and the United Kingdom. Endorsement notice The text of ISO 28706-4:2016 has been approved by CEN as EN ISO 28706-4:2016 without any modification. DIN EN ISO 28706-4:2016-07 EN ISO 28706-4:2016 (E) 3 ForewordISO (the International Organization for Standardization) is a worldwide federation of natio

27、nal 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 committee. Internati

28、onal 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.The procedures used to develop this document and those intended

29、 for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different 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

30、.org/directives).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. Details of any patent rights identified during the development of the document will

31、be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). 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 meaning of ISO specific terms and expressio

32、ns related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information.The committee responsible for this document is ISO/TC 107, Metallic and other inorganic coatings

33、.This third edition cancels and replaces the second edition (ISO 28706-4:2008), of which it constitutes a minor revision.ISO 28706 consists of the following parts, under the general title Vitreous and porcelain enamels Determination of resistance to chemical corrosion: Part 1: Determination of resis

34、tance to chemical corrosion by acids at room temperature Part 2: Determination of resistance to chemical corrosion by boiling acids, boiling neutral liquids and/or their vapours Part 3: Determination of resistance to chemical corrosion by alkaline liquids using a hexagonal vessel Part 4: Determinati

35、on of resistance to chemical corrosion by alkaline liquids using a cylindrical vessel Part 5: Determination of resistance to chemical corrosion in closed systemsDIN EN ISO 28706-4:2016-07 EN ISO 28706-4:2016 (E) 4 IntroductionCorrosion of vitreous and porcelain enamels by aqueous solutions is a diss

36、olution 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 hydrolysed as well and form the correspondi

37、ng 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, the

38、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 corrosio

39、n 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 0,1 m

40、ol/l NaOH (see Clause 9 of this part of ISO 28706), the silica network of the enamel is considerably attacked at 80 C. Silicates and most of the other hydrolysed components are soluble in the alkali. Attack proceeds linearly during regular test times. Therefore, test results are expressed in terms o

41、f a rate 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 28706-1:2008, Clause 9) or also in stronger acids like sulfuric acid (see ISO 28706-1:2008, Clause 10), there

42、is only 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

43、 28706-2), 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 surfa

44、ce. The acid 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

45、 of any dissolved enamel constituents.Examples of enamel corrosion proceeding in a logarithmic manner see 1) and linearly see 2) are:1) Boiling citric acid (see of ISO 28706-2:2008, Clause 10) and boiling 30 % sulfuric acid (see ISO 28706-2:2008, Clause 11)Since only minor amounts of these acids are

46、 found in their 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) Boi

47、ling 20 % hydrochloric acid (see ISO 28706-2:2008, Clause 12)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 line

48、arly with time of exposure. Therefore, DIN EN ISO 28706-4:2016-07 EN ISO 28706-4:2016 (E) 5 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).d) At high temperatures, with tests in the liquid phase under autoclave conditions (see ISO 28706-5), aqueous acid attack is severe. To avoid inhibition, the test time i