Vitreous and porcelain enamels - Determination of resistance to chemical corrosion - Part 3: Determination of resistance to chemical corrosion by alkaline liquids using a hexagonal vessel (ISO 28706-3:2008)

ISO 28706-3:2008 describes a test method for the determination of the resistance of vitreous and porcelain enamelled articles to attack by alkaline liquids at temperatures between 25 °C and 95 °C. The apparatus used is a hexagonal vessel in which six enamelled specimens are simultaneously tested.

Emails und Emaillierungen - Bestimmung der Beständigkeit gegen chemische Korrosion - Teil 3: Bestimmung der Beständigkeit gegen chemische Korrosion durch alkalische Flüssigkeiten unter Verwendung eines Gerätes mit hexagonalem Gefäß (ISO 28706-3:2008)

Dieser Teil von ISO 28706 legt ein Prüfverfahren zur Bestimmung der Beständigkeit von emaillierten
Gegenständen gegen den Angriff alkalischer Flüssigkeiten bei Temperaturen zwischen 25 °C und 95 °C fest.
Das verwendete Gerät ist ein hexagonales Gefäß, in dem sechs emaillierte Proben gleichzeitig geprüft
werden können.
ANMERKUNG 1 Die Beständigkeit gegen sämtliche alkalische Flüssigkeiten kann bestimmt werden. Das Verfahren
wurde jedoch ursprünglich zur Bestimmung der Beständigkeit gegen heiße Waschmittellösungen im neutralen und
alkalischen Bereich erarbeitet, die zum Waschen von Textilien verwendet werden.
ANMERKUNG 2 Da Waschmittel laufend Rezepturänderungen unterliegen, ist eine Standard-Prüflösung festgelegt
worden, die hinsichtlich Alkalität, Benetzungsvermögen und Komplexbildungsverhalten als eine typische Rezeptur für die
auf dem Markt befindlichen Waschmittel gelten kann. Der pH-Wert und die Alkalität der Standard-Prüflösung ergibt sich
aus den vorhandenen Anteilen an Natriumtripolyphosphat, Natriumcarbonat und Natriumperborat; Natriumtripolyphosphat
dient gleichzeitig als Komplexbildner. Das Benetzungsvermögen der Standard-Prüflösung wird durch den Zusatz von
Alkylsulfonat erreicht. Ein höherer Gehalt an Natriumperborat wird nicht für notwendig gehalten, da die Wirkung von
Sauerstoff auf Email unbedeutend ist und eine Erhöhung des Gehaltes an Perborat keine wesentliche Änderung der
Alkalität der Standard-Prüflösung zur Folge hat. Die Prüfung verschiedener Emails mit dieser Standard-Prüflösung und
anderen Prüflösungen (einschließlich Natriumpyrophosphat-Lösung mit einem Massenanteil von 5 %) rechtfertigt die
Verwendung dieser Standard-Prüflösung zur Bestimmung der Beständigkeit von Emails gegen heiße Waschmittellösungen.

Émaux vitrifiés - Détermination de la résistance à la corrosion chimique - Partie 3: Détermination de la résistance à la corrosion chimique par des liquides alcalins dans un récipient hexagonal (ISO 28706-3:2008)

L'ISO 28706-3:2008 spécifie une méthode d'essai permettant de déterminer la résistance d'articles en émail vitrifié à l'attaque par des liquides alcalins à des températures comprises entre 25 °C et 95 °C. L'appareillage utilisé est un récipient hexagonal dans lequel six éprouvettes émaillées sont soumises à essai simultanément.

Steklasti in porcelanski emajli - Ugotavljanje odpornosti proti kemični koroziji - 3. del: Ugotavljanje odpornosti proti kemični koroziji z alkalnimi tekočinami in šesterokotno posodo (ISO 28706-3:2008)

Ta del ISO 28706 opisuje preskusno metodo za ugotavljanje odpornosti steklastih in porcelanskih emajliranih predmetov proti napadu z alkalnimi tekočinami pri temperaturah med 25 °C in 95 °C. Uporabljeni aparat je šesterokotna posoda, v kateri se istočasno preskuša šest emajliranih vzorcev.

General Information

Status
Withdrawn
Publication Date
22-Nov-2011
Withdrawal Date
15-Mar-2018
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
15-Mar-2018
Due Date
07-Apr-2018
Completion Date
16-Mar-2018

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SLOVENSKI STANDARD
SIST EN ISO 28706-3:2012
01-januar-2012
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SIST EN 14483-3:2004

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GHO8JRWDYOMDQMHRGSRUQRVWLSURWLNHPLþQLNRUR]LML]DONDOQLPLWHNRþLQDPLLQ
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Vitreous and porcelain enamels - Determination of resistance to chemical corrosion -

Part 3: Determination of resistance to chemical corrosion by alkaline liquids using a

hexagonal vessel (ISO 28706-3:2008)

Emails und Emaillierungen - Bestimmung der Beständigkeit gegen chemische Korrosion

- Teil 3: Bestimmung der Beständigkeit gegen chemische Korrosion durch alkalische

Flüssigkeiten unter Verwendung eines Gerätes mit hexagonalem Gefäß (ISO 28706-
3:2008)

Émaux vitrifiés - Détermination de la résistance à la corrosion chimique - Partie 3:

Détermination de la résistance à la corrosion chimique par des liquides alcalins dans un

récipient hexagonal (ISO 28706-3:2008)
Ta slovenski standard je istoveten z: EN ISO 28706-3:2011
ICS:
25.220.50 Emajlne prevleke Enamels
SIST EN ISO 28706-3:2012 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 28706-3:2012
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SIST EN ISO 28706-3:2012
EUROPEAN STANDARD
EN ISO 28706-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2011
ICS 25.220.50 Supersedes EN 14483-3:2004
English Version
Vitreous and porcelain enamels - Determination of resistance to
chemical corrosion - Part 3: Determination of resistance to
chemical corrosion by alkaline liquids using a hexagonal vessel
(ISO 28706-3:2008)

Émaux vitrifiés - Détermination de la résistance à la Emails und Emaillierungen - Bestimmung der Beständigkeit

corrosion chimique - Partie 3: Détermination de la gegen chemische Korrosion - Teil 3: Bestimmung der

résistance à la corrosion chimique par des liquides alcalins Beständigkeit gegen chemische Korrosion durch alkalische

dans un récipient hexagonal (ISO 28706-3:2008) Flüssigkeiten unter Verwendung eines Gerätes mit

hexagonalem Gefäß (ISO 28706-3:2008)
This European Standard was approved by CEN on 15 April 2011.

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 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, 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 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, France, Germany, 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 STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 28706-3:2011: E

worldwide for CEN national Members.
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SIST EN ISO 28706-3:2012
EN ISO 28706-3:2011 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST EN ISO 28706-3:2012
EN ISO 28706-3:2011 (E)
Foreword

The text of ISO 28706-3:2008 has been prepared by Technical Committee ISO/TC 107 “Metallic and other

inorganic coatings” of the International Organization for Standardization (ISO) and has been taken over as EN

ISO 28706-3:2011 by 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 publication of an identical

text or by endorsement, at the latest by November 2011, and conflicting national standards shall be withdrawn

at the latest by November 2011.

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 be held responsible for identifying any or all such patent rights.

This document supersedes EN 14483-3:2004.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland and the United Kingdom.
Endorsement notice

The text of ISO 28706-3:2008 has been approved by CEN as a EN ISO 28706-3:2011 without any

modification.
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SIST EN ISO 28706-3:2012
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SIST EN ISO 28706-3:2012
INTERNATIONAL ISO
STANDARD 28706-3
First edition
2008-12-01
Vitreous and porcelain enamels —
Determination of resistance to chemical
corrosion —
Part 3:
Determination of resistance to chemical
corrosion by alkaline liquids using a
hexagonal vessel
Émaux vitrifiés — Détermination de la résistance à la corrosion
chimique —
Partie 3: Détermination de la résistance à la corrosion chimique par des
liquides alcalins dans un récipient hexagonal
Reference number
ISO 28706-3:2008(E)
ISO 2008
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SIST EN ISO 28706-3:2012
ISO 28706-3:2008(E)
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ii © ISO 2008 – All rights reserved
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SIST EN ISO 28706-3:2012
ISO 28706-3:2008(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope..................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Principle................................................................................................................................................. 1

4 Reagents................................................................................................................................................ 2

5 Apparatus and materials...................................................................................................................... 2

6 Test specimens..................................................................................................................................... 7

7 Procedure.............................................................................................................................................. 7

8 Expression of results........................................................................................................................... 7

9 Standard detergent solution test ........................................................................................................ 8

9.1 General................................................................................................................................................... 8

9.2 Test solution.......................................................................................................................................... 8

9.3 Test temperature................................................................................................................................... 8

9.4 Duration of the test............................................................................................................................... 8

9.5 Test report............................................................................................................................................. 9

10 Other test solutions and/or conditions............................................................................................... 9

10.1 General................................................................................................................................................... 9

10.2 Test solution.......................................................................................................................................... 9

10.3 Test temperature................................................................................................................................... 9

10.4 Duration of the test............................................................................................................................... 9

10.5 Test report........................................................................................................................................... 10

© ISO 2008 – All rights reserved iii
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SIST EN ISO 28706-3:2012
ISO 28706-3:2008(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national 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. International 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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 28706-3 was prepared by the European Committee for Standardization (CEN) (as EN 14483-3) and was

adopted, under a special “fast-track procedure”, by Technical Committee ISO/TC 107, Metallic and other

inorganic coatings, in parallel with its approval by the ISO member bodies.

It cancels and replaces ISO 4533:1983 and ISO 4535:1983, which have been technically revised.

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 resistance 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: Determination of resistance to chemical corrosion by alkaline liquids using a cylindrical vessel

⎯ Part 5: Determination of resistance to chemical corrosion in closed systems
iv © ISO 2008 – All rights reserved
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SIST EN ISO 28706-3:2012
ISO 28706-3:2008(E)
Introduction

Corrosion of vitreous and porcelain enamels by aqueous solutions is a dissolution process. The main

component of the enamel, SiO , 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 corresponding 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 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/m⋅h) be

calculated as well as a corrosion rate (mm/year).

The most important parameters influencing aqueous corrosion 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 mol/l NaOH (see Clause 9 of ISO 28706-4:2008), 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 of 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 Clause 9 of ISO 28706-1:2008) or also in

stronger acids like sulfuric acid (see Clause 10 of ISO 28706-1:2008), there 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 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 surface. 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 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 Clause 10 of ISO 28706-2:2008) and boiling 30 % sulfuric acid (see

Clause 11 of ISO 28706-2:2008)

Since only minute amounts of these acids are 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) Boiling 20 % hydrochloric acid (see Clause 12 of ISO 28706-2:2008)

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 of exposure. Therefore, test results are only

© ISO 2008 – All rights reserved v
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SIST EN ISO 28706-3:2012
ISO 28706-3:2008(E)

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),

...

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