BS EN ISO 8044:2020 pdf – 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. NOTE 1 Throughout the document, IUPAC rules for electrode potential signs are applied. The term “metal” is also used to include alloys and other metallic materials. NOTE 2 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 terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .iso .org/ obp — IEC Electropedia: available at http:// www .electropedia .org/ 3.1 corrosion physicochemical interaction between a metallic material and its environment that results in changes in the properties of the metal, and that may lead to significant impairment of the function of the metal, the environment or the technical system, of which these form a part Note 1 to entry: This interaction is often of an electrochemical nature. 3.2 corrosive agent substance that will initiate or promote 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 may 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
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 may vary with time and may 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 <corrosion> ability of a corrosion system (3.4) to perform its specified functions without impairment due to corrosion (3.1) 3.17 durability <corrosion> 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
3.19 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 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