BS ISO 22410:2020 pdf free.Corrosion of metals and alloys – Electrochemical measurement of iontransfer resistance to characterize the protective rust layer on weathering steel.
BS ISO 22410 This document specifies a method for the electrochemical measurement of ion transfer resistance of the rust layer formed on weathering steel alloys in order to assess their protective properties against corrosion thereafter[3]. This method uses an electrochemical AC impedance measurement[4][5][6] [7][8], together with harmonic analysis, to identify the ion transfer resistance, and a rust thickness measurement to characterize the stability of the protective rust layer in terms of corrosion protection under used environments.The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.ISO 2178, Non-magnetic coatings on magnetic substrates 一Measurement of coating thickness-Magnetic method ISO 9223, Corrosion of metals and alloys 一Corrosivity of atmospheres一Classification, determination and estimation.For the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses:一ISO Online browsing platform: available at hts://wwwiso.org/obp一IEC Electropedia: available at http://www.electropedia.org/Based on the cross-sectional microscopic observations of numerous rust layers on weathering steels
exposed to various locations for various periods (see Figure 2 and Reference [3]), the rust layers can be typically classified into three types: initial rust (unknown), protective rust and anomalous rust (unprotective).a) Initial rust: Islands of thin amorphous (very fine crystals) rust are visible at the steel-rust interface under a crystalline rust layer. The total thickness is usually less than 400 um. The rust layer can be observed either at the initial stage of service or after long-term exposure to a mildly corrosive environment. The corrosion loss of the steel is very small.b) Protective rust: An amorphous or very fine crystalline rust layer covers the whole surface area under the crystalline rust layer (FeOOH). The total thickness is usually between 40 μm and 400 um.This is the ideal protective rust layer for weathering steel. c Anomalous rust: Fe0OH exists both at the external surface and along crack surfaces. The rest of the rust consists of crystalline Fe304 (usually confirmed by X-ray analysis). The total thickness is more than 400 um. The rust contains numerous cracks, sometimes bearing sea salt. It tends to
form when the wetting period is excessive and/or accumulated salt is present. BS ISO 22410 pdf download.