METHOD TO APPLY PROTECTIVE ANTICORROSION ZINC COATING ONTO METAL SURFACE Russian patent published in 2013 - IPC F42B5/26 F42B5/28 F42B5/295 

FIELD: weapons and ammunition.

SUBSTANCE: method to apply a protective anticorrosion zinc coating onto a metal surface consists in degreasing of the surface, etching, washing and application of the coating galvanically. The coating is applied on the surface of metal elements of a cartridge, containing one type of metal at the end - steel or lead or brass. The coating is applied first by means of surface etching in the sulfuric acid solution with concentration of 100-200 g/l and sodium chloride in amount of 65-120 g/l for 2-6 minutes, roughness is created. After washing a zinc coating is formed on the outer surface of the cartridge elements in four stages. At the first stage the layer of the zinc coating is applied to thickness of 2-4 mcm in electrolyte, with current density of 0.2-1.0 A/dm² for 30-40 minutes. At the second stage, in another bath, the thickness of zinc layer is increased to 4-6 mcmc in electrolyte, with current density of 0.2-1.0 A/dm² for 40-50 minutes. At the third stage in the third bath the applied coating is exposed to clarification in the nitric acid solution with concentration of 3-6 g/l for 10-60 sec. At the fourth stage passivation is carried out in the fourth bath with electrolyte, for 10-30 seconds with subsequent washing and drying.

EFFECT: improved quality of a zinc coating.

6 dwg