Phosphating process of metal surface
AssigneeNippon Paint Co., Ltd.
InventorsRyoichi Murakami, Hideo Shimizu, Takashi Yoshii, Minoru Ishida, Hiroto Yonekura
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Abstract
A process for phosphating a metal surface to be electrocoated, which comprises treating the metal surface with an acidic phosphating solution comprising a zinc compound in a concentration of 0.5 to 1.5 g/l as zinc ion, a phosphate in a concentration of 5 to 30 g/l as phosphate ion and a nitrite in a concentration of 0.01 to 0.2 g/l as nitrite ion and/or an aromatic nitro compound in a concentration of 0.05 to 2 g/l in water at a temperature of 40 to 70.degree. C. first by dipping for not less than 15 seconds and then by spraying for not less than 2 seconds.
Claims3
In a process for forming an electrocoated film on the surface of a metal substrate by subjecting said metal surface to phosphating and then to cationic electrocoating, the improvement wherein the phosphating consists essentially of first dipping the metal surface into an acidic phosphating solution consisting essentially of a zinc compound in a concentration of 0.5 to 1.5 g/l as a zinc ion, a phosphate in a concentration of 5 to 30 g/l as a phosphate ion and a nitrite in a concentration of 0.01 to 0.2 g/l as a nitrite ion and/or an aromatic nitro compound in a concentration of 0.05 to 2 g/l in water and a chlorate in a concentration of 0.05 to 2 g/l as a chlorate ion, at a temperature of 40.degree. to 70.degree. C. for not less than 15 seconds and then spraying the metal surface with said acidic phosphate solution for not less than 2 seconds.
Dependencies are inferred from the claim text.