Solution composition for steel sheet surface treatment, steel sheet surface-treated using same, and manufacturing method therefor

Abstract

The present invention relates to a solution composition capable of improving pitting corrosion resistance and blackening resistance of a steel sheet, a steel sheet surface-treated using same, and a method for manufacturing the steel sheet.

1 . A solution composition for a surface treatment of a steel sheet, the solution composition comprising:
 (a) 20 to 60 wt % of trivalent chromium compound,   (b) 0.1 to 10 wt % of acidity regulator,   (c) 1 to 20 wt % of adhesion improver,   (d) 1 to 20 wt % of corrosion resistance improver,   (e) 0.01 to 3.0 wt % of pitting corrosion improver,   (f) 1 to 20 wt % of co-solvent, and   (g) a residual solvent   
     
     
         2 . The solution composition of  claim 1 , wherein the trivalent chromium compound is one or more selected from the group consisting of chromium sulfate, chromium nitrate, chromium phosphate, chromium fluoride, chromium chloride, and mixtures thereof. 
     
     
         3 . The solution composition of  claim 1 , wherein the acidity regulator is one or more selected from the group consisting of phosphoric acid, nitric acid, sulfuric acid, hydrofluoric acid, hydrochloric acid, (NH 4 ) H 2 PO 4 , (NH 4 ) 2 HPO 4 , NaH 2 PO 4 , Na 2 HPO 4 , phytic acid, glycolic acid, lactic acid, acetic acid, oxalic acid, and mixtures thereof. 
     
     
         4 . The solution composition of  claim 1 , wherein the adhesion improver is one or more selected from the group consisting of vinyl methoxy silane, vinyl trimethoxy silane (VTMS), vinyl epoxy silane, vinyl triepoxy silane, 3-aminopropyltriepoxy silane, 3-glycidoxypropyltrimethoxy silane, 3-metaglyoxypropyltrimethoxy silane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxytrimethyldimethoxysilane, N-(3-(trimethoxysilyl) propyl)ethylenediamine (AEAPTMS), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(2,3-epoxypropoxy) propyltrimethoxysilane, 3-(2,3-epoxypropoxy) propyltriethoxysilane, 3-(2,3-epoxypropoxy) propylmethyldiethoxysilane, 3-(2,3-epoxypropoxy) propylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl-3-aminopropyl)methyldimethoxysilane, N-(2-aminoethyl-3-aminopropyl) trimethoxysilane, diethylenetriaminopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, N-phenylaminopropyltrimethoxysilane, (3-glycidyloxypropyl) trimethoxysilane (GPTMS), methyltrimethoxysilane (MTMS), and mixtures thereof. 
     
     
         5 . The solution composition of  claim 1 , wherein the corrosion resistance improver is one or more selected from the group consisting of vanadyl acetylacetonate, ammonium metavanadate, potassium metavanadate, sodium metavanadate, vanadium trioxide, vanadium acetylacetate, ammonium metavanadate, silicon oxide, and mixtures thereof. 
     
     
         6 . The solution composition of  claim 1 , wherein the pitting corrosion improver is one or more selected from the group consisting of ethylenediamine, hexamethylenediamine, trimethylamine, methylamine, diphenylamine, ethyleneamine, aniline, toluidine, piperidine, aziridine, pyridine, alanine, propylamine, diisopropylamine, monoisopropylamine, dibutylamine, dipropylamine, and mixtures thereof. 
     
     
         7 . The solution composition of  claim 1 , wherein the co-solvent is one or more selected from the group consisting of ethanol, isopropyl alcohol, methanol, tallow alcohol, 2-butoxyethanol, diethylene glycol monobutyl ether, and mixtures thereof. 
     
     
         8 . The solution composition of  claim 1 , wherein the solvent is water. 
     
     
         9 . A surface-treated plated steel sheet comprising:
 a steel sheet;   a Zn—Mg—Al-based plating layer formed on at least one surface of the steel sheet; and   a surface treated coating layer formed on the plating layer,   wherein the surface treated coating layer is a coating layer formed from the composition of  claim 1 .   
     
     
         10 . The surface-treated plated steel sheet of  claim 9 , wherein
 the Zn—Mg—Al-based plating layer includes, in wt %, magnesium (Mg): 4.0 to 7.0%, aluminum (Al): 11.0 to 19.5%, a balance of Zn, and other inevitable impurities, and satisfies the following Relational Expression 1:   
       
         
           
             
               
                 
                   
                     0.26 
                     ≤ 
                     
                       
                         I 
                         ⁡ 
                         ( 
                         110 
                         ) 
                       
                       / 
                       
                         I 
                         ⁡ 
                         ( 
                         103 
                         ) 
                       
                     
                     ≤ 
                     0.65 
                   
                 
                 
                   
                     [ 
                     
                       Relational 
                       ⁢ 
                           
                       Expression 
                       ⁢ 
                           
                       1 
                     
                     ] 
                   
                 
               
             
           
         
         (In Relational Expression 1, I (110) represents an X-ray diffraction integrated intensity of the (110) plane crystal peak for the MgZn 2  phase, and I (103) represents the represents an X-ray diffraction integrated intensity of the (103) plane crystal for the MgZn 2  phase.) 
       
     
     
         11 . The surface-treated plated steel sheet of  claim 9 , wherein the surface treated coating layer has a thickness of 0.1 to 2.0 μm. 
     
     
         12 . A method of manufacturing a surface-treated plated steel sheet, the method comprising:
 hot-dip galvanizing at least one surface of a steel sheet to form a Zn—Mg—Al-based plating layer;   coating the plating layer with the composition of  claim 1 ; and   drying the coated steel sheet.   
     
     
         13 . The method of  claim 12 , wherein the coating is performed by one method selected from the group consisting of bar coating, roll coating, spraying, dipping, spray squeezing, and immersion squeezing. 
     
     
         14 . The method of  claim 12 , wherein the drying is carried out in a temperature range of 40 to 280° C. based on a peak metal temperature (PMT) of the steel sheet.