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US 12,686,909 B2Granted
Surface modifying method for galvanized steel sheet
AssigneePosco
InventorsYon-Kyun Song, Yun-Ha Yoo, Joong-Chul Park, Hyun-Ju Jeong, Jae-Dong Cho
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Abstract
A galvanized steel sheet according to one aspect of the present invention comprises: a base steel sheet; and a Zn—Al—Mg-based plating layer provided on at least one surface of the base steel sheet, wherein the Zn—Al—Mg-based plating layer may include a surface modified region enriched with cerium (Ce) on a surface layer side of the Zn—Al—Mg-based plating layer.
Claims3
A surface modifying method for a galvanized steel sheet, comprising:
- a first step of preparing a galvanized steel sheet having a Zn—Al—Mg-based plating layer on at least one surface of a base steel sheet;
- a second step of preparing an aqueous cerium nitrate solution by dissolving 15 to 25 g of cerium nitrate per 1000 ml of water (H2O) and adjusting the pH to 3.2 to 3.8 by titrating with nitric acid (HNO3);
- a third step of immersing the galvanized steel sheet in the aqueous cerium nitrate solution;
- and
- a fourth step of washing and drying the galvanized steel sheet that has been immersed in the aqueous cerium nitrate solution.
2 more elements
Dependencies are inferred from the claim text.