ASTM International

Standard Specification for Chromium Free Zinc-Flake Composite, with or without Integral Lubricant, Corrosion Protective Coatings for Fasteners
 N F3019/F3019M

Annotation

This specification covers the basic requirements for non-electrolytically applied zinc-flake composite corrosion protective coating systems for fasteners (See Note 1).

NOTE 1—The coating systems do not contain hexavalent chromium, lead, cadmium, or mercury.

This specification is intended for corrosion protection of inch and metric series threaded fasteners with minimum nominal diameters of 0.250 in. for inch series and [6.00 mm] for metric as well as for non-threaded fasteners such as washers and pins.

This coating system may be specified to consist of a zinc-flake basecoat, or a zinc-flake basecoat and topcoat (See Note 2).

NOTE 2—For threaded fasteners, the coating system will typically consist of a zinc-flake basecoat and topcoat.

The basecoat is a zinc-rich material containing aluminum flakes dispersed in a compatible liquid medium. The zinc-flake basecoat may be specified to contain integral lubricant.

Topcoats may be organic or inorganic in composition depending upon the specified requirements.

Organic topcoats consist of polymer resins, aluminum, dispersed pigments, and are colored in their applied state.

Inorganic topcoats consist of water-dispersed silicate compounds and are transparent in their applied state.

Topcoats contain integral lubricants and are applied in conjunction with zinc-flake basecoats to form a coating system with enhanced performance attributes such as increased corrosion resistance, total coefficient of friction properties, chemical resistance, and color.