ASTM | Standard Specification for Zinc-Flake Coating Systems for Fasteners
Zinc-flake coating systems are fluid dispersions of zinc-flakes, sometimes with the addition of aluminum flakes, which are non-electrolytically applied to steel substrates. The zinc-flake coating system shall be supplied without hexavalent chromium and can be water based or solvent based systems. Cohesion among the zinc-flakes and adhesion to the steel substrate is achieved through a matrix that is formed during the curing process.
This specification covers the classification, performance, and basic requirements for non-electrolytically applied zinc-flake coatings on unified inch and metric series threaded fasteners with minimum nominal diameters of 0.250 in. for inch series and 6 mm for metric.
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