Surface-treated steel sheet and method of producing same
AssigneeJfe Steel Corporation
InventorsTakashi UENO, Yusuke NAKAGAWA
Life of this patent
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Abstract
Provided is a surface-treated steel sheet that can be produced without the use of hexavalent chromium and that has excellent adhesion to BPA-free paint. A surface-treated steel sheet having, on at least one surface of a steel sheet, a Ni-containing layer and a coating layer disposed on the Ni-containing layer and containing at least one of Zr oxide and Ti oxide, wherein a contact angle of ethylene glycol is 50° or less, and a total atomic ratio of K, Na, Mg, and Ca adsorbed on a surface of the steel sheet to all elements is 5.0% or less.
Claims6
A surface-treated steel sheet comprising, on at least one side of a steel sheet,
- a Ni-containing layer;
- and
- a coating layer disposed on the Ni-containing layer and containing at least one of Zr oxide and Ti oxide, wherein
- a contact angle of ethylene glycol is 500 or less, and
- a total atomic ratio of K, Na, Mg, and Ca adsorbed on a surface of the steel sheet to all elements is 5.0% or less.
A method of producing a surface-treated steel sheet comprising, on at least one side of a steel sheet, a Ni-containing layer, and a coating layer disposed on the Ni-containing layer and containing at least one of Zr oxide and Ti oxide, the method comprising:
- a coating formation process of treating a surface of a steel sheet having a Ni-containing layer on at least one side with an aqueous solution containing at least one of Zr ions and Ti ions to form the coating layer on the Ni-containing layer;
- a surface conditioning process of holding the aqueous solution at 1.0 g/m2 to 30.0 g/m2 on a surface of the coating layer for 0.1 seconds to 20.0 seconds;
- and
- a water washing process of subjecting the steel sheet after the surface conditioning process to water washing at least once, wherein
- in the water washing process,
- water with an electrical conductivity of 100 μS/m or less is used at least in the last water washing.
Dependencies are inferred from the claim text.