SIST EN ISO 8044:2025

SLOVENSKI STANDARD
01-marec-2025
Korozija kovin in zlitin - Slovar (ISO 8044:2024)
Corrosion of metals and alloys - Vocabulary (ISO 8044:2024)
Korrosion von Metallen und Legierungen - Grundbegriffe (ISO 8044:2024)
Corrosion des métaux et alliages - Vocabulaire (ISO 8044:2024)
Ta slovenski standard je istoveten z: EN ISO 8044:2025
ICS:
01.040.77 Metalurgija (Slovarji) Metallurgy (Vocabularies)
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8044
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2025
EUROPÄISCHE NORM
ICS 01.040.77; 77.060 Supersedes EN ISO 8044:2020
English Version
Corrosion of metals and alloys - Vocabulary (ISO
8044:2024)
Corrosion des métaux et alliages - Vocabulaire (ISO Korrosion von Metallen und Legierungen - Begriffe
8044:2024) (ISO 8044:2024)
This European Standard was approved by CEN on 22 December 2024.

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8044:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8044:2025) has been prepared by Technical Committee ISO/TC 156 "Corrosion
of metals and alloys" 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
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 July 2025, and conflicting national standards shall be
withdrawn at the latest by July 2025.
Attention is drawn 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 8044:2020.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 8044:2024 has been approved by CEN as EN ISO 8044:2025 without any modification.

International
Standard
ISO 8044
Sixth edition
Corrosion of metals and alloys —
2024-12
Vocabulary
Corrosion des métaux et alliages — Vocabulaire
Reference number
ISO 8044:2024(en) © ISO 2024
ISO 8044:2024(en)
© ISO 2024
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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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 8044:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms related to corrosion in general . 1
4 Terms related to types of corrosion . 3
5 Terms related to corrosion protection . 9
6 Terms related to corrosion testing . 10
7 Terms related to electrochemical matters .11
7.1 Electrochemical cell .11
7.2 Reaction rates . 15
7.3 Passivation .17
7.4 Electrochemical protection . .18
7.5 Electrochemical corrosion tests .19
Annex A (informative) Graphical representations of certain terms .21
Bibliography .23
Index .24

iii
ISO 8044:2024(en)
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.
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 different approval criteria needed for the different types
of ISO document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 262,
Metallic and other inorganic coatings, including for corrosion protection and corrosion testing of metals and
alloys, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This sixth edition cancels and replaces the fifth edition (ISO 8044:2020) which has been technically revised.
The main changes are as follows:
— several definitions have been changed, including the definition of corrosion;
— several editorial changes were made, including the addition of cross-references to other terms within the
definitions.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 8044:2024(en)
Introduction
The definitions in this document have been drawn up with the objective of achieving a proper balance
between precision and simplicity. The main objective of this document is to provide definitions that can be
understood to have the same meaning by all concerned. Some corrosion terms in present use have developed
through common usage and are not always logical. It has not, therefore, been possible to define certain terms
in the form they are used in some countries. Because of the occasional conflicts between tradition and logic,
some definitions inevitably represent a compromise.
An example of this kind of conflict is the term “corrosion”. This has been used to mean the process, the
results of the process and the damage caused by the process. In this document, corrosion is understood to
mean the process. Any detectable result of corrosion in any part of a corrosion system is termed “corrosion
effect”. The term “corrosion damage” covers any impairment of the function of the technical system of which
the metal and the environment form a part. Consequently, the term “corrosion protection” implies that
the important thing is to avoid corrosion damage rather than to prevent corrosion, which in many cases is
impossible and sometimes not necessary.

v
International Standard ISO 8044:2024(en)
Corrosion of metals and alloys — Vocabulary
1 Scope
This document defines terms relating to corrosion that are widely used in modern science and technology.
In addition, some definitions are supplemented with short explanations.
Throughout the document, International Union of Pure and Applied Chemistry rules for electrode potential
signs are applied. The term “metal” is also used to include alloys and other metallic materials.
Terms and definitions related to the inorganic surface treatment of metals are given in ISO 2080.
2 Normative references
There are no normative references in this document.
3 Terms related to corrosion in general
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
corrosion
chemical or electrochemical interaction between a material, usually a metal, and its environment
Note 1 to entry: This can lead to deterioration of material properties, the environment or the function of the system
containing that material.
3.2
corrosive agent
substance that initiates or promotes corrosion (3.1) when in contact with a given metal
3.3
corrosive environment
environment that contains one or more corrosive agents (3.2)
3.4
corrosion system
system consisting of one or more metals and those parts of the environment that influence corrosion (3.1)
Note 1 to entry: Parts of the environment can be, for example, coatings, surface layers or additional electrodes (7.1.2).
3.5
corrosion effect
change in any part of the corrosion system (3.4) caused by corrosion (3.1)
3.6
corrosion damage
corrosion effect (3.5) that causes impairment of the function of the metal, the environment or the technical
system of which these form a part

ISO 8044:2024(en)
3.7
corrosion failure
corrosion damage (3.6) characterized by the total loss of function of the technical system
3.8
corrosion product
substance formed as a result of corrosion (3.1)
3.9
scale
solid layer of corrosion products (3.8) formed on a metal at high temperature
Note 1 to entry: The term “scale” is also used in some countries for deposits from supersaturated water.
3.10
rust
visible corrosion products (3.8) consisting mainly of hydrated iron oxides
3.11
corrosion depth
distance between a point on the surface of a metal affected by corrosion (3.1) and the original surface of the metal
3.12
corrosion rate
corrosion effect (3.5) on a metal per unit time
Note 1 to entry: The unit used to express the corrosion rate depends on the technical system and on the type of
corrosion effect. Thus, corrosion rate is typically expressed as an increase in corrosion depth (3.11) per unit time, or
the mass of metal turned into corrosion products (3.8) per area of surface and per unit time, etc. The corrosion effect
can vary with time and will not be the same at all points of the corroding surface. Therefore, reports of corrosion rates
are typically accompanied by information on the type, time dependency and location of the corrosion effect.
3.13
corrosion resistance
ability of a metal to maintain serviceability (3.16) in a given corrosion system (3.4)
3.14
corrosivity
ability of an environment to cause corrosion (3.1) of a metal in a given corrosion system (3.4)
3.15
corrosion likelihood
qualitative and/or quantitative expression of the expected corrosion effects (3.5) in a defined corrosion
system (3.4)
3.16
serviceability
ability of a corrosion system (3.4) to perform its specified functions without impairment due to corrosion (3.1)
3.17
durability
ability of a corrosion system (3.4) to maintain serviceability (3.16) over a specified time when the specified
requirements for use and maintenance have been fulfilled
3.18
service life
time during which a corrosion system (3.4) meets the requirements for serviceability (3.16)
3.19
critical humidity
value of the relative humidity of an atmosphere above which there is a sharp increase in the corrosion rate
(3.12) of a given metal
ISO 8044:2024(en)
3.20
corrosion attack
corrosion effect (3.5) that is detrimental but has not progressed to the point of impairment of the function of
the metal, the environment or the technical system of which these form a part
3.21
pickling
removal of oxides or other compounds from a metal surface by chemical or electrochemical action
3.22
pitting resistance equivalent number
PREN
indication of the resistance of stainless steels and nickel-based alloys to pitting in the presence of chloride-
containing water
Note 1 to entry: An example formula for PREN is given by:
PREN=+%,Cr 33 %,Mo +05 %%WN+16
[]() () ()
Note 2 to entry: In general, the higher the PREN, the higher the resistance to pitting corrosion (4.15).
3.23
trap
micro structural site at which the residence time for a hydrogen atom is long compared to the residence time
in an interstitial lattice site
3.24
time of wetness
period when a metallic surface is covered by adsorptive and/or liquid films of electrolyte (7.1.1) to be capable
of causing atmospheric corrosion (4.4)
3.25
threshold stress
tensile stress above which stress corrosion cracks initiate and grow for specified test conditions
3.26
threshold stress intensity factor for stress corrosion cracking
K
ISCC
stress intensity factor above which stress corrosion crack propagation is sustained
Note 1 to entry: The threshold stress intensity factor is a concept of linear elastic fracture mechanics (LEFM) and is
applicable when the plastic zone size is large compared with the microstructure, the crack is sufficiently long, and a high
constraint to plastic deformation prevails, i.e. under plane strain predominant conditions. For growing stress corrosion
cracks, LEFM is not necessarily applicable in all detail but is adopted as a pragmatic tool that is commonly used.
Note 2 to entry: Stress corrosion cracks can initiate at a surface or a surface defect and grow in the “small crack”
regime at stress intensity factor levels below the apparent threshold stress intensity factor. Therefore, LEFM is not
applicable in the “small crack” regime.
4 Terms related to types of corrosion
4.1
electrochemical corrosion
corrosion (3.1) involving at least one anodic reaction (7.1.9) and one cathodic reaction (7.1.6)
4.2
chemical corrosion
corrosion (3.1) not involving an electrochemical reaction

ISO 8044:2024(en)
4.3
gaseous corrosion
corrosion (3.1) with dry gas as the corrosive environment (3.3) and without any liquid phase on the surface of
the metal
4.4
atmospheric corrosion
corrosion (3.1) with the earth's atmosphere at ambient temperature as the corrosive environment (3.3)
4.5
marine corrosion
corrosion (3.1) with sea water as the main agent of the corrosive environment (3.3)
Note 1 to entry: This definition includes both immersed and splash zone conditions.
4.6
underground corrosion
corrosion (3.1) of buried metals, soil being the corrosive environment (3.3)
Note 1 to entry: The term "soil" includes not only the naturally occurring material but also any other material, such as
ballast and backfill, used to cover a structure.
4.7
bacterial corrosion
microbiologically influenced corrosion (4.37) due to the action of bacteria
4.8
general corrosion
corrosion (3.1) proceeding over the whole surface of the metal exposed to the corrosive environment (3.3)
4.9
uniform corrosion
general corrosion (4.8) proceeding at almost the same rate over the whole surface
4.10
localized corrosion
corrosion (3.1) preferentially concentrated on discrete sites of the metal surface exposed to the corrosive
environment (3.3)
Note 1 to entry: Localized corrosion can result in, for example, pits, cracks or grooves.
4.11
galvanic corrosion
corrosion (3.1) due to the action of a corrosion cell (7.1.13)
Note 1 to entry: The term has often been restricted to the action of bimetallic corrosion cells, i.e. to bimetallic
corrosion (4.12).
4.12
bimetallic corrosion
DEPRECATED: contact corrosion
galvanic corrosion (4.11) where the electrodes (7.1.2) are formed by dissimilar metals
4.13
impressed current corrosion
electrochemical corrosion (4.1) due to the action of an external source of electric current
4.14
stray-current corrosion
impressed current corrosion (4.13) caused by current flowing through paths other than the intended circuits

ISO 8044:2024(en)
4.15
pitting corrosion
localized corrosion (4.10) resulting in cavities extending from the surface into the metal
4.16
crevice corrosion
localized corrosion (4.10) associated with, and taking place in or immediately around, a narrow aperture or
clearance formed between the metal surface and another surface (metallic or non-metallic)
4.17
deposit corrosion
localized corrosion (4.10) associated with, and taking place under or immediately around, a deposit of
corrosion products (3.8) or other substance
4.18
water-line corrosion
corrosion (3.1) along, and as a consequence of the presence of, a gas/liquid boundary
4.19
selective corrosion
dealloying
corrosion (3.1) of an alloy whereby the components react in proportions that differ from their proportions in
the alloy
4.20
dezincification of brass
selective corrosion (4.19) of brass resulting in the preferential removal of zinc
4.21
graphitic corrosion
selective corrosion (4.19) of grey cast iron resulting in the partial removal of metallic constituents and
leaving graphite
4.22
intergranular corrosion
corrosion (3.1) in or adjacent to the grain boundaries of a metal
4.23
weld corrosion
corrosion (3.1) associated with the presence of a welded joint and taking place in the weld or its vicinity
4.24
knife-line corrosion
corrosion (3.1) resulting in a narrow slit in or adjacent to the filler/parent boundary of a welded or brazed joint
4.25
erosion corrosion
process involving conjoint corrosion (3.1) and erosion
Note 1 to entry: Erosion corrosion can occur in, for example, pipes with high fluid flow velocity and pumps and pipe
lines carrying fluid containing abrasive particles in suspension or entrained in a gas flow.
4.26
cavitation corrosion
process involving conjoint corrosion (3.1) and cavitation
Note 1 to entry: Cavitation corrosion can occur, for example, in rotary pumps and on ships' propellers.

ISO 8044:2024(en)
4.27
fretting corrosion
process involving conjoint corrosion (3.1) and oscillatory slip between two vibrating surfaces in contact
Note 1 to entry: Fretting corrosion can occur, for example, at mechanical joints in vibrating structures.
4.28
wear corrosion
process involving conjoint corrosion (3.1) and friction between two sliding surfaces in contact
4.29
corrosion fatigue
process involving conjoint corrosion (3.1) and alternating straining of the metal, often leading to cracking
Note 1 to entry: Corrosion fatigue can occur when a metal is subjected to cyclic straining in a corrosive environment (3.3).
4.30
stress corrosion
process involving conjoint straining of a material, usually a metal, due to applied or residual stress, and
corrosion (3.1) of that material
4.31
stress corrosion cracking
cracking due to stress corrosion (4.30)
4.32
hydrogen embrittlement
process resulting in a decrease of the toughness or ductility of a metal due to absorption of hydrogen
Note 1 to entry: Hydrogen embrittlement often accompanies hydrogen formation, for example, by corrosion (3.1) or
electrolysis. This can lead to cracking.
4.33
blistering
process resulting in a dome-shaped defect visible on the surface of an object and arising from localized loss
of cohesion below the surface
Note 1 to entry: For example, blistering can occur on coated metal due to loss of adhesion between coating and
substrate, caused by accumulation of products from localized corrosion (4.10). On uncoated metal, blistering can occur
due to excessive internal hydrogen pressure.
4.34
spalling
fragmentation and detachment of portions of the surface layer or scale (3.9)
4.35
tarnishing
dulling, staining or discoloration of a metal surface, due to the formation of a thin layer of corrosion products (3.8)
4.36
aqueous corrosion
corrosion (3.1) with water or a water-based solution as the corrosive environment (3.3)
4.37
microbiologically influenced corrosion
MIC
corrosion (3.1) influenced by the action of microorganisms
Note 1 to entry: Compare with bacterial corrosion (4.7).

ISO 8044:2024(en)
4.38
environmentally assisted cracking
cracking of a susceptible material, usually a metal, due to the conjoint action of its environment and
mechanical stress
4.39
hydrogen-induced cracking
HIC
planar cracking that occurs in metals due to induced stresses when atomic hydrogen diffuses into the metal
and then combines to form molecular hydrogen at trap (3.23) sites
4.40
hydrogen stress cracking
HSC
cracking that results from the presence of hydrogen in a metal and tensile stress (residual or applied or both)
Note 1 to entry: HSC describes cracking in metals that are not sensitive to sulfide stress corrosion cracking (4.43)
but which can be embrittled by hydrogen when galvanically coupled, as the cathode (7.1.3), to another metal that
is corroding actively as an anode (7.1.4). The term “galvanically induced HSC” has been used for this mechanism of
cracking.
4.41
irradiation-assisted stress corrosion cracking
intergranular cracking of austenitic stainless steels resulting from a reduction in the chromium
concentration in a very narrow band at the grain boundaries following exposure to high neutron irradiation
doses exceeding one displacement per atom which causes the migration of point defects to the grain
boundaries
4.42
stepwise cracking
SWC
cracking that connects hydrogen-induced cracks (HICs) (4.39) on adjacent planes in a metal
Note 1 to entry: This term describes the crack appearance. The linking of hydrogen-induced cracks to produce
stepwise cracking is dependent upon local strain between the cracks and embrittlement of the surrounding metal by
dissolved hydrogen. HIC (4.39)/SWC (4.42) is usually associated with low-strength plate steels used in the production
of pipes and vessels.
4.43
sulfide stress corrosion cracking
SSCC
cracking of metal involving corrosion (3.1) and tensile stress, residual and/or applied, in the presence of
water and hydrogen sulfide
Note 1 to entry: SSCC is a form of hydrogen stress cracking (4.40) and involves embrittlement of the metal by atomic
hydrogen that is produced by acid corrosion on the metal surface. Hydrogen uptake is promoted in the presence of
sulfides. The atomic hydrogen can diffuse into the metal, reduce ductility and increase susceptibility to cracking. High
strength metallic materials and hard weld zones are prone to SSCC.
4.44
stress-oriented hydrogen-induced cracking
SOHIC
staggered small cracks formed approximately perpendicular to the principal stress (residual or applied)
resulting in a “ladder-like” crack array linking (sometimes small) pre-existing hydrogen-induced cracking
(HIC) (4.39) cracks
Note 1 to entry: The mode of cracking can be categorised as stress corrosion cracking (SCC) (4.31) caused by a
combination of external stress and the local strain around hydrogen-induced cracks. SOHIC is related to SCC and HIC/
stepwise cracking (4.42). It has been observed in parent material of longitudinally welded pipe and in the heat-affected
zone of welds in pressure vessels. SOHIC is a relatively uncommon phenomenon usually associated with low-strength
ferritic pipe and pressure vessel steels.

ISO 8044:2024(en)
Note 2 to entry: Compare with hydrogen embrittlement (4.32).
[SOURCE: ISO 15156-1:2020, 3.23, modified — Note 2 to entry has been added.]
4.45
exfoliation corrosion
stratified form of subsurface stress corrosion (4.30) of susceptible primary wrought alloy mill products
having a highly directional grain structure, accompanied by detachment of separate layers from the body of
the material, formation of cracks and finally usually complete layer-by-layer disintegration of metal
Note 1 to entry: Exfoliation generally proceeds along grain boundaries, but with certain alloys and tempering it can
develop along transgranular paths or a mixed intergranular/transgranular path.
Note 2 to entry: Layer corrosion can be developed on the first stage.
4.46
filiform corrosion
type of corrosion (3.1) proceeding under coating materials on metals in the form of threads, generally
starting from bare edges or from local damage to the coating
Note 1 to entry: Usually, the threads are irregular in length and direction of growth, but they can also be nearly parallel
and of approximately equal length. Filiform corrosion can occur under different protective coatings (5.5).
4.47
tribo-corrosion
any form of corrosion (3.1) that involves constant removal of the passive layer (7.3.6) due to fluid or particle
impact on the corroding surface or the friction between the corroding surface and another surface
Note 1 to entry: Tribo-corrosion includes but is not restricted to: wear corrosion (4.28), fretting corrosion (4.27) and
erosion corrosion (4.25).
Note 2 to entry: This process can result in an increase in friction of bearing surfaces in addition to causing material loss.
4.48
impingement attack
form of erosion corrosion (4.25) in aqueous liquids under high velocity or turbulent flow conditions on the
metal surface causing repetitive disruption of protective films leading to accelerated localised corrosion (4.10)
4.49
high temperature corrosion
corrosion (3.1) by gases or deposits or both occurring at elevated temperatures under conditions where
aqueous electrolytes (7.1.1) no longer exist
Note 1 to entry: High temperature corrosion can become significant at temperatures above 170 °C depending on
...