A Preface
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This document is prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9, General Test methods for paints and varnishes.

The third edition eliminates and replaces the second edition (ISO 4628-10:2016), which has been technically revised.

ISO 4628-10-2016 – Assessment of ageing of paints and varnish coatings – Assessment of the number and size of defects and the intensity of uniform changes in appearance – Part 10: Assessment of the degree of filamentous corrosion

The main changes are as follows:

– The title has been shortened to “Paints and varnishs-Assessment of the number and size of defects, and the intensity of uniform changes in appearance – Part 10: Assessment of the degree of filamentous corrosion”

— The definition of filamentous corrosion (3.1) has been consistent with ISO 4623-1:2018;

– The meaning of annex A has been truncated;

-Text has been edited and revised and normative references have been updated.

A list of all parts in the ISO 4628 series can be found on the ISO website.

Any feedback or questions regarding this document should be directed to the user’s national standards body. A full list of these agencies can be found at iso.org/members.html.

ISO 4628-10-2016 – Assessment of ageing of paints and varnish coatings – Assessment of the number and size of defects and the intensity of uniform changes in appearance – Part 10: Assessment of the degree of filamentous corrosion

1 Scope
This document specifies a method for assessing the amount of filamentation corrosion produced by marking by measuring the length of the longest filament, L, and the common length, M.

The graphical examples provided in Annex A to this document illustrate the different levels of the degree of filamentous corrosion. Comparing the test panel with the 12 pictures in Annex A does not replace the mandatory numerical assessment (methods 1 or 2).

ISO 4628-1 defines the system used to specify the number and size of defects and the intensity of uniform changes in coating appearance and Outlines the general principles of this system. The system is particularly suitable for defects caused by aging and weathering, as well as uniform changes, such as color changes, such as yellowing.

2 Normative references
The following documents are referenced in the text in such a way that some or all of their contents constitute the requirements of this document. For dated references, only the cited version applies. For undated references, the new version of the reference (including any revisions) applies.

ISO 13076, Paints and varnishes – Lighting and procedures for visual assessment of coatings

ISO 4628-10-2016 – Assessment of ageing of paints and varnish coatings – Assessment of the number and size of defects and the intensity of uniform changes in appearance – Part 10: Assessment of the degree of filamentous corrosion

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for standardization at the following addresses:

– ISO online browsing platform: available at iso.org/obp

– IEC Electronic Encyclopedia: available at electropedia.org/

3.1 Filamentous corrosion

The type of corrosion that occurs in the form of threads under coatings of paints, varnishes, or related products, usually starts with exposed edges or local damage of the coating

Note 1: Usually the length and growth direction of the lines are irregular, but they can also be almost parallel and roughly equal in length. They usually follow the extrusion direction and do not cross each other. They need to be triggered by invasive ions.

[Source: ISO 4623-1:2018, 3.1]

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