DIN EN ISO 4628-8:2013-03

This part of ISO 4628 specifies a method for assessing delamination and corrosion around a scribe or other artificial defect on a coated panel or other coated test specimen, caused by a corrosive environment. This part of ISO 4628 does not cover evaluation of pitting corrosion, pit depth, etcetera. Examples of corrosive environments are artificial atmospheres such as salt spray, as used in the test method specified in ISO 9227, and sea water immersion as used in the test method specified in ISO 15711 and natural environments. ISO 4628-1 defines the system for designating the quantity and size of defects and the intensity of uniform changes in appearance of coatings and outlines the general principles of the system. The system is intended to be used, in particular, for defects caused by ageing and weathering, and for uniform changes such as colour changes, for example yellowing. The other parts of ISO 4628 provide pictorial standards or other means for evaluating particular types of defect. As far as possible, already existing evaluation schemes have been used as the basis. After exposure of a coated test panel with a scribe or other artificial defect in a corrosive environment, one, or a combination of both of, the following phenomena can occur around the scribe or other artificial defect: - delamination; - corrosion. Delamination and corrosion around the scribe or other artificial defect are evaluated separately to provide more detailed information about the performance of a coating system in corrosive environments. In addition to the procedure specified in this part of ISO 4628, assessments of delamination and corrosion around the scribe or other artificial defect may be carried out using optical image processing. Rating of other defects is described in other parts of ISO 4628. The committee responsible for this standard is NA 002-00-07 AA "Allgemeine Prüfverfahren für Beschichtungsstoffe und Beschichtungen" ("General test methods for coating materials and coatings") at DIN.