Abstract: The present invention relates to a surface-treated substrate having excellent corrosion resistance and capable of developing color on the surface, and to a substrate surface treatment method for same. The surface-treated substrate, according to the present invention, comprises a coating having a uniform thickness on a metal matrix, thereby improving corrosion resistance and evenly developing color on the surface. Also, by comprising a wavelength conversion layer and a top coat, in order, on top of the coating, the advantage of improving scratch resistance and durability of the substrate without discoloring of the achieved color can be provided.

Abstract: A coating composition for zinc- and zinc alloy-coated steel sheets includes: 1 to 30% by weight of hypophosphorous acid, 0.1 to 10% by weight of manganese, 0.01 to 5% by weight of a polyvinyl compound, zinc oxide and the balance of water, and further comprises 20% by weight or less of alcohol, when necessary, wherein the zinc oxide is included in such a content that, when 50 Ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 Ml (milliliters) or less, and a content of free acid in the coating composition is adjusted to such an amount that, when 50 Ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 Ml (milliliters) or less.

Abstract: A coating composition for zinc- and zinc alloy-coated steel sheets includes: 1 to 30% by weight of hypophosphorous acid, 0.1 to 10% by weight of manganese, 0.01 to 5% by weight of a polyvinyl compound, zinc oxide and the balance of water, and further comprises 20% by weight or less of alcohol, when necessary, wherein the zinc oxide is included in such a content that, when 50 Ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 Ml (milliliters) or less, and a content of free acid in the coating composition is adjusted to such an amount that, when 50 Ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 Ml (milliliters) or less.