Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

A molybdate solution is disclosed from which molybdate oxide coatings may be derived on metal particles or metal mesh. The coated metal particles may then be combined with a film forming binder and, optionally, corrosion inhibitors to make a corrosion composition. The coated metal mesh may then be used in making gaskets that inhibit corrosion.

A molybdate solution is disclosed from which molybdate oxide coatings may be derived on metal particles or metal mesh. The coated metal particles may then be combined with a film forming binder and, optionally, corrosion inhibitors to make a corrosion composition. The coated metal mesh may then be used in making gaskets that inhibit corrosion.

A steel sheet mainly suitable for strength members of automobiles or building materials, which has a tensile strength of 1,180 MPa or more, and which is excellent in delayed fracture resistance and primary rust prevention performance. The steel sheet includes a coating, placed on a surface of a cold-rolled steel sheet with a tensile strength of 1,180 MPa or more, containing one or more metalates selected from molybdates and tungstates and a P compound. The sum of the coating weights of the metalates in terms of Mo and W is 10 mg/m.sup.2 to 1,000 mg/m.sup.2 and is preferably 50 mg/m.sup.2 to 1,000 mg/m.sup.2. The coating weight of the P compound in terms of P is 10 mg/m.sup.2 to 1,000 mg/m.sup.2.

A steel sheet mainly suitable for strength members of automobiles or building materials, which has a tensile strength of 1,180 MPa or more, and which is excellent in delayed fracture resistance and primary rust prevention performance. The steel sheet includes a coating, placed on a surface of a cold-rolled steel sheet with a tensile strength of 1,180 MPa or more, containing one or more metalates selected from molybdates and tungstates and a P compound. The sum of the coating weights of the metalates in terms of Mo and W is 10 mg/m.sup.2 to 1,000 mg/m.sup.2 and is preferably 50 mg/m.sup.2 to 1,000 mg/m.sup.2. The coating weight of the P compound in terms of P is 10 mg/m.sup.2 to 1,000 mg/m.sup.2.

The present invention relates to a four-function steel surface treatment liquid and a preparation method thereof, the components of raw materials of the four-function steel surface treatment liquid per liter include: phytic acid of 15 g-18 g, hydroxyethylidene-1, 1-diphosphonic acid of 50 g-65 g, phosphoric acid solution of 280 g-320 g, manganous dihydrogen phosphate of 280 g-360 g, thiourea of 5 g-8 g, surfactant of 3 g-6 g, polyethylene glycol of 1 g-2 g, sodium molybdate of 5 g-8 g, and the remaining of water. The four-function steel surface treatment liquid provided by the present invention has the advantages of a good anti-corrosion property and a safe cleaning process, is simple, high efficiency, environmental protection, no hydrogen embrittlement on a metal substrate, no intergranular corrosion, no harm to human skin, no burning, no explosion, and non-toxic, and can be used repeatedly at a normal temperature.

A surface-treated steel material having cut edge corrosion resistance that is equal to or more than that of a chromate treatment without use of hexavalent chromium. The surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer that is obtained by immersing the steel material in a galvalume bath containing Mg. The coating film is formed using a coating composition containing a coating film-forming resin, a cross-linking agent, a predetermined vanadium compound, and trimagnesium phosphate; the vanadium compound is a compound satisfying a predetermined electrical conductivity; the content of the vanadium compound is restricted to a predetermined amount; the vanadium compound satisfies a predetermined pH; and the content of the trimagnesium phosphate is a predetermined amount.

A surface-treated steel material having cut edge corrosion resistance that is equal to or more than that of a chromate treatment without use of hexavalent chromium. The surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer that is obtained by immersing the steel material in a galvalume bath containing Mg. The coating film is formed using a coating composition containing a coating film-forming resin, a cross-linking agent, a predetermined vanadium compound, and trimagnesium phosphate; the vanadium compound is a compound satisfying a predetermined electrical conductivity; the content of the vanadium compound is restricted to a predetermined amount; the vanadium compound satisfies a predetermined pH; and the content of the trimagnesium phosphate is a predetermined amount.

A grain-oriented electrical steel sheet according to one embodiment of the present invention includes a steel sheet and an insulation coating, in which the insulation coating contains a first metal phosphate, which is a metal phosphate of one or two more metals selected from Al, Fe, Mg, Mn, Ni, and Zn; a second metal phosphate, which is a metal phosphate of one or two more metals selected from Co, Mo, V, W, and Zr; and colloidal silica, the insulation coating does not contain chromate, and an elution amount of phosphoric acid of the insulation coating as determined by boiling the grain-oriented electrical steel sheet in a boiled pure water for 10 minutes, then measuring an elution amount of phosphoric acid into the pure water, and dividing the amount of phosphoric acid by the area of the insulation coating of the boiled grain-oriented electrical steel sheet is 30 mg/m.sup.2 or less.

A grain-oriented electrical steel sheet according to one embodiment of the present invention includes a steel sheet and an insulation coating, in which the insulation coating contains a first metal phosphate, which is a metal phosphate of one or two more metals selected from Al, Fe, Mg, Mn, Ni, and Zn; a second metal phosphate, which is a metal phosphate of one or two more metals selected from Co, Mo, V, W, and Zr; and colloidal silica, the insulation coating does not contain chromate, and an elution amount of phosphoric acid of the insulation coating as determined by boiling the grain-oriented electrical steel sheet in a boiled pure water for 10 minutes, then measuring an elution amount of phosphoric acid into the pure water, and dividing the amount of phosphoric acid by the area of the insulation coating of the boiled grain-oriented electrical steel sheet is 30 mg/m.sup.2 or less.