ISO 22858:2020

Corrosion of metals and alloys — Electrochemical measurements — Test method for monitoring atmospheric corrosion

This document specifies a test method for atmospheric corrosion measurements, using two-electrode electrochemical sensors. It is applicable to measurements of the corrosion rate of uncoupled metal surfaces (i.e. "free" corrosion rate), galvanic corrosion rate, conductance of thin film solutions and barrier properties of organic coatings. It specifies electrochemical sensors that are used with or without organic coatings. The sensors are applicable to corrosion measurements made in laboratory test chambers, outdoor exposure sites and service environments.

Corrosion des métaux et alliages — Mesures électrochimiques — Méthode d'essai pour la surveillance de la corrosion atmosphérique

General Information

• Status: Published
• Publication Date: 16-Aug-2020
• ICS: 77.060 - Corrosion of metals
• Technical Committee: ISO/TC 156 - Corrosion of metals and alloys
• Drafting Committee: ISO/TC 156/WG 11 - Electrochemical test methods
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Jul-2025
• Completion Date: 15-Jul-2025

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22858
First edition
2020-08
Corrosion of metals and alloys —
Electrochemical measurements
— Test method for monitoring
atmospheric corrosion
Corrosion des métaux et alliages — Mesures électrochimiques —
Méthode d'essai pour la surveillance de la corrosion atmosphérique
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Summary of sensors . 2
5 Free corrosion current sensor . 3
5.1 Free corrosion current sensor description . 3
5.2 Sensor geometry . 3
5.3 Uniform corrosion current measurement . 3
5.3.1 Use and conditions for uniform corrosion measurements. 3
5.3.2 Method 1 — Sine wave excitation . 3
5.3.3 Method 2 — Triangle wave excitation . 3
5.3.4 Method 3 — Potential step excitation . 3
5.4 Localized corrosion current measurement . 4
5.5 Free corrosion rate and total free corrosion for sensors without coatings . 4
5.5.1 Free corrosion current and current density. 4
5.5.2 Free corrosion penetration rate . 4
5.5.3 Free corrosion mass loss rate . 5
5.5.4 Total free corrosion mass loss and corrosion penetration . 5
5.6 Free corrosion current and total charge for sensors with coatings . 5
5.6.1 Use and conditions for free corrosion measurements with coatings . 5
5.6.2 Free corrosion current for a coated sensor . 5
5.6.3 Free corrosion total charge for a coated sensor . 5
5.7 Free corrosion sensor preparation . 5
5.7.1 Considerations for free corrosion sensor surface preparation . 5
5.7.2 Free corrosion sensors without coatings . 6
5.7.3 Free corrosion sensors with coatings and surface treatments . 6
5.8 Specification and inspection — Free corrosion sensors . 6
5.8.1 Visual inspection . 6
5.8.2 Sensor range and span . 7
5.8.3 Electrical verification tests . 7
5.8.4 Corrosion verification tests . 7
6 Galvanic corrosion current sensor . 7
6.1 Galvanic corrosion current sensor description. 7
6.2 Sensor geometry . 7
6.3 Galvanic corrosion current measurements . 8
6.3.1 Methods for galvanic corrosion current measurement . 8
6.3.2 Method 1 — Zero-resistance ammeter . 8
6.3.3 Method 2 — Precision resistor . 8
6.4 Galvanic corrosion rate and total galvanic corrosion without coatings . 8
6.4.1 Galvanic corrosion current . 8
6.4.2 Galvanic corrosion rate for mass loss and corrosion penetration . 8
6.4.3 Total galvanic corrosion mass loss and corrosion penetration . 8
6.5 Galvanic corrosion rate and total galvanic corrosion with coatings . 9
6.5.1 Use and conditions for galvanic corrosion measurements with coatings . 9
6.5.2 Galvanic mass loss corrosion rate for a coated sensor . 9
6.5.3 Total galvanic mass loss for a coated sensor. 9
6.6 Galvanic corrosion sensor preparation . 9
6.6.1 Considerations for galvanic corrosion sensor preparation . . 9
6.6.2 Galvanic corrosion sensors without coatings . 9
6.6.3 Galvanic corrosion sensors with coatings and surface treatments . 9
6.7 Specification and inspection — Galvanic corrosion sensors . 9
6.7.1 Visual, span and range inspection . 9
6.7.2 Electrical verification tests . 9
6.7.3 Corrosion verification tests .10
7 Thin film conductance sensors .10
7.1 Conductance sensor description .10
7.2 Sensor geometry .10
7.3 Surface conductance measurement method .10
7.4 Surface conductance sensor preparation .10
7.5 Specification and inspection — Conductance sensor .10
7.5.1 Visual, span and range inspection .10
7.5.2 Electrical verification tests .10
7.5.3 Conductive solution verification tests .11
8 Coating barrier property sensors .11
8.1 Coating barrier property sensor description .11
8.2 Coating barrier property measurements .11
8.3 Coating barrier property sensor preparation .11
8.3.1 Sensor preparation for coating .11
8.3.2 Coating test condition.11
8.4 Specification and inspection — Coating barrier property sensor .12
8.4.1 Visual, span and range inspection .12
8.4.2 Electrical measurements .12
8.4.3 Sensing system impedance verification tests .12
9 Atmospheric testing with electrochemical sensors .12
9.1 Types of atmospheric tests .12
9.2 Test arrangement .12
9.3 Test duration .12
9.4 Sensor selection .12
9.5 Sampling time interval .12
9.6 Date and time information .13
10 Test report .13
10.1 Test report guidance .
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