Preparation of steel substrates before application of paints and related products - Tests for the assessment of surface cleanliness - Part 2: Laboratory determination of chloride on cleaned surfaces
|Publication Date:||1 January 2017|
|ICS Code (Surface preparation):||25.220.10|
This part of ISO 8502 describes a method for the determination of chloride-containing salts that are readily soluble in water and are present on a steel surface. The method is also applicable to previously coated surfaces. This part of ISO 8502 includes a method, applicable in the field or in the laboratory, for washing off the surface while several methods are referred to for chloride analyses.
NOTE 1 ISO 8502-5 describes a field test for the determination of chloride on a surface.
NOTE 2 The precision of the method is limited by both the accuracy of the selected method of analyses and by uncertainties in the sampling procedure. The extraction method might not take all the water soluble material off the surface due to
- soluble material hiding in crevices, under folds of metal or at the bottom of pits, and
- soluble material hiding under corrosion layers, passivation layers, inhibitors, oil, grease, or other non-visible thin films as these boundary layers can prevent contact with the underlying salt for its removal.
NOTE 3 The performance of a paint system is affected by the amount of soluble chloride remaining on the surface. The acceptable level of this contamination is related to the service conditions. For further information regarding levels of water-soluble salt contamination, see ISO/TR 15235.