ZINC-CHROMATE COATING ON THE STEELS (VERSIONS) Russian patent published in 2007 - IPC C23C28/00 C25D5/48 

FIELD: chemical industry; metal-working industry; other industries; methods of the corrosion protection of the steels by application of the zinc-chromate coatings.

SUBSTANCE: the invention is pertaining to the field of the corrosion protection of the metals and may be used for the protection of the steel articles against corrosion by means of the multilayer coatings. The zinc-chromate coating on the steel contains the zinc layer produced out of the sulfate electrolyte, and the external chromate layer. At that the coating in addition contains the inner electric current- conductive chromate layer produced out of the solution, (g/dm³): CrO₃ - 8, HNO₃ - 4, Na₂SO₄ - 12, Cr₂(SO₄)_3·18H₂O - 5, Na₂SnO_3·3H₂O - 8. The zinc-chromate coating on the steel contains the zinc layer produced out of the sulfate electrolyte, and the outer chromate layer. At that the zinc-chromate coating additionally contains the inner electric current conductive chromate layer produced out of the solution, (g/dm³): CrO₃ - 8, Na₂SO₄ - 12, Cr₂(SO₄)_{3 ·}18 H₂O - 5, In(NO₃)₃ - 6. The technical result of the invention is the raise of the protective capability of the zinc-chromate coating on the steel on the average in 2 times.

EFFECT: the invention ensures the increased protective capability of the zinc-chromate coating on the steel on the average in 2 times.

1 dwg, 4 ex