BS 7371-9:1996

This Part of BS 7371 specifies requirements for phosphate or phosphate and oil coatings on metal fasteners and accessories, applied by immersion or spraying.

NOTE 1. Phosphate coatings are primarily intended for application to ferrous, zinc or zinc alloy fasteners.

NOTE 2. Phosphate coatings can be used as an undercoat to improve the corrosion resistance and adhesion of a subsequently applied top coat (e.g. organic coating).

NOTE 3. Phosphate coatings can be used to impart a controlled torque/clamping force relationship to a threaded fastener (see BS 7371 : Part 2 : 1993).

This Part of BS 7371 should be read in conjuction with the requirements for phosphate and phosphate and oil coatings of BS 7371 : Part 1 General requirements and selection guidelines.

This Part of BS 7371 also specifies requirements for the following:

1. the minimum coating mass per unit area;

2. assessment of the corrosion resistance of unused coated parts when subjected to neutral salt spray testing (see for example BS 7479 : 1991).