Typical coatings that can be evaluated with this method are:
*Phosphated (pre-treated) surfaces (with subsequent paint/primer/lacquer/rust preventive)
*Zinc and zinc-alloy plating (see also electroplating). See ISO 4042 for guidance
*Electroplated chromium, nickel, copper, tin
*Coatings not applied electrolytically, such as zinc flake coatings according to ISO 10683
*Organic coatings, such as rust preventives
*Paint Coating
Hot-dip galvanized surfaces are not generally tested in a salt spray test (see ISO 1461 or ISO 10684). Hot-dip galvanizing produces zinc carbonates when exposed to a natural environment, thus protecting the coating metal and reducing the corrosion rate. The zinc carbonates are not produced when a hot-dip galvanized specimen is exposed to a salt spray fog, therefore this testing method does not give an accurate measurement of corrosion protection. ISO 9223 gives the guidelines for proper measurement of corrosion resistance for hot-dip galvanized specimens.
Painted surfaces with an underlying hot-dip galvanized coating can be tested according to this method. See ISO 12944-6.
Testing periods range from a few hours (e.g. 8 or 24 hours of phosphated steel) to more than a month (e.g. 720 hours of zinc-nickel coatings, 1000 hours of certain zinc flake coatings).