Claims
- 1. A method for preparing a chromate-treated zinc-plated steel strip, comprising
- effecting cathodic electrolysis on a zinc-plated steel strip in a bath containing 2.6 to 78 grams per liter of hexavalent chromium, 0.5 to 50 grams per liter, calculated as SiO.sub.2, of colloidal silica, and 0.05 to 5.0 grams per liter, calculated as F, of a fluoride, and substantially free of sulfate and chloride, at a current density of 1 to 50 A/dm.sup.2 and to an electricity quantity of 5 to 100 C/dm.sup.2.
- 2. A method for preparing a chromate-treated zinc-plated steel strip, comprising
- effecting cathodic electrolysis on a zinc-plated steel strip in a bath containing 2.6 to 78 grams per liter of hexavalent chromium, 0.5 to 50 grams per liter, calculated as SiO.sub.2, of colloidal silica, 0.05 to 25 grams per liter, calculated as Al.sub.2 O.sub.3, of alumina sol, and 0.05 to 5.0 grams per liter, calculated as F, of a fluoride, and substantially free of sulfate and chloride, at a current density of 1 to 50 A/dm.sup.2 and to an electricity quantity of 5 to 100 C/dm.sup.2.
- 3. A method for preparing a chromate-treated zinc-plated steel strip, comprising
- effecting cathodic electrolysis on a zinc-plated steel strip in a bath containing 2.6 to 78 grams per liter of hexavalent chromium, 0.5 to 50 grams per liter, calculated as SiO.sub.2, of colloidal silica, and 0.05 to 5.0 grams per liter, calculated as F, of a fluoride, and substantially free of sulfate and chloride, at a current density of 1 to 50 A/dm.sup.2 and to an electricity quantity of 5 to substantially less than 30 C/dm.sup.2.
- 4. A method for preparing a chromate-treated zinc-plated steel strip, comprising
- effecting cathodic electrolysis on a zinc-plated steel strip in a bath containing 2.6 to 78 grams per liter of hexavalent chromium, 0.5 to 50 grams per liter, calculated as SiO.sub.2, of colloidal silica, 0.05 to 25 grams per liter, calculated as Al.sub.2 O.sub.3, of alumina sol, and 0.05 to 5.0 grams per liter, calculated as F, of a fluoride, and substantially free of sulfate and chloride, at a current quantity density of 1 to 50 A/dm.sup.2 and to an electric of 5 to substantially less than 30 C/dm.sup.2.
Priority Claims (1)
Number |
Date |
Country |
Kind |
61-116642 |
May 1986 |
JPX |
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Parent Case Info
This application is a division, of application Ser. No. 020,015, filed 2/26/87 now U.S. Pat. No. 4,804,587.
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4137132 |
Ward et al. |
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4548868 |
Yohezawa et al. |
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4659394 |
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Apr 1987 |
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Foreign Referenced Citations (4)
Number |
Date |
Country |
1621075 |
Apr 1971 |
DEX |
42-14050 |
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JPX |
47-44417 |
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JPX |
60-110896 |
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JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
20015 |
Feb 1987 |
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