This specification covers the basic requirements and associated test methods for water-based corrosion protective zinc/aluminum dispersion inorganic basecoats, and optional sealers and topcoats for fasteners. The basecoat can contain chrome (C) or be non-chrome (NC). These coatings are applied to ferrous parts by conventional dip-spin, dip-drain, or spray methods, which can be handled through a cleaning, coating, and baking operation, and which are not adversely affected by baking temperatures up to 626 °F. The coatings are classified into six grades (Grades 1 to 6) according to the required minimum basecoat thickness, and when tested, shall conform accordingly to appearance, adhesion, corrosion resistance, blister, thread fit, and hydrogen embrittlement requirements. The coating process does not induce the possibility of internal hydrogen embrittlement provided that the fasteners have not been cleaned or pre-treated with an acid or phosphate. Alkaline cleaning or vapor degreasing is required along with shot blasting to remove rust or scale. No metric equivalents are presented in this specification.

1.1 This specification covers the basic requirements for water-based zinc/aluminum dispersion inorganic basecoats and optional sealers and topcoats for fasteners. The basecoat can contain chrome (C) or be non-chrome (NC).

1.2 These coatings are applied by conventional dip-spin, dip-drain, or spray methods to ferrous parts which can be handled through a cleaning, coating, and baking operation, and which are not adversely affected by baking temperatures up to 626°F.

1.3 The coating process does not induce the possibility of internal hydrogen embrittlement providing that the fasteners have not been cleaned or pre-treated with an acid or phosphate. Alkaline cleaning or vapor degreasing is required along with shot blasting to remove rust or scale.

1.4 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.