The present invention provides a chromium-free coating composition having high blackening resistance and corrosion resistance, the composition comprising: 20 to 70 wt % of waterborne silane modified polyurethane; 0.5 to 5 wt % of a hardener; 0.5 to 5 wt % of a blackening inhibitor; 0.5 to 5 wt % of a corrosion inhibitor; and 0.5 to 5 wt % of a lubricant, with the balance being a solvent. The chromium-free coating composition has the effect of improving blackening resistance, corrosion resistance, alkali resistance, solvent resistance and fingerprint resistance of a steel sheet on which a coating layer comprising the composition is formed.

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO.sub.2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO.sub.2; and H.sub.3PO.sub.4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:
0.20([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]0.45(1).

A grain-oriented electrical steel sheet has a steel sheet and an insulating coating which is formed on a surface of the steel sheet. In the insulating coating, a metal phosphate and a colloidal silica are contained, the colloidal silica is contained in an amount of 20 to 150 parts by mass with respect to 100 parts by mass of the metal phosphate, one or more kinds of fine particles selected from the group consisting of silicon carbide, silicon nitride, aluminum nitride, boron nitride, sialon, and cordierite are further contained in an amount of 0.5 to 7 parts by mass with respect to 100 parts by mass of the metal phosphate, an average particle size of the fine particles is 0.3 to 7.0 m, crystallized ratio of the metal phosphate is 2% to 40%, and chromium is not contained.

A coating, a method for coating surfaces, and the coated surfaces. The method includes providing a substrate with a cleaned metal surface; contacting and coating the metal surface with an aqueous composition having a ph of from 0.5 to 7.0 and in the form of a dispersion and/or a suspension; optionally rinsing the organic coating; and drying and/or baking the organic coating, or optionally drying the organic coating and coating same with a similar or another coating composition thereto. The composition contains a complex fluoride in a quantity of 1.1 10.sup.6 mol/l to 0.30 mol/l based on the cations. An anionic polyelectrolyte in a quantity of 0.01 to 5.0 wt % based on the total mass of the resulting mixture is added to an anionically stabilized dispersion made of film-forming polymers and/or a suspension made of film-forming inorganic particles.

A coating, a method for coating surfaces, and the coated surfaces. The method includes providing a substrate with a cleaned metal surface; contacting and coating the metal surface with an aqueous composition having a ph of from 0.5 to 7.0 and in the form of a dispersion and/or a suspension; optionally rinsing the organic coating; and drying and/or baking the organic coating, or optionally drying the organic coating and coating same with a similar or another coating composition thereto. The composition contains a complex fluoride in a quantity of 1.1 10.sup.6 mol/l to 0.30 mol/l based on the cations. An anionic polyelectrolyte in a quantity of 0.01 to 5.0 wt % based on the total mass of the resulting mixture is added to an anionically stabilized dispersion made of film-forming polymers and/or a suspension made of film-forming inorganic particles.

There is provided a grain-oriented electrical steel sheet stably having excellent magnetic characteristics and coating adhesion even when a rapid heating is conducted in a primary recrystallization annealing (decarburization annealing). Concretely, it is a grain-oriented electrical steel sheet provided on its sheet surface with a tension-applying type insulation coating constituted with a coating layer A formed on a steel sheet side and mainly composed of an oxide and a coating layer B formed on a surface side and mainly composed of glass, characterized in that a ratio R (.sub.B/.sub.A) of a tension .sub.B of the coating layer B on the surface side applied to the steel sheet to a tension .sub.A of the coating layer on the steel sheet side A applied to the steel sheet is within a range of 1.20-4.0.

There is provided a grain-oriented electrical steel sheet stably having excellent magnetic characteristics and coating adhesion even when a rapid heating is conducted in a primary recrystallization annealing (decarburization annealing). Concretely, it is a grain-oriented electrical steel sheet provided on its sheet surface with a tension-applying type insulation coating constituted with a coating layer A formed on a steel sheet side and mainly composed of an oxide and a coating layer B formed on a surface side and mainly composed of glass, characterized in that a ratio R (.sub.B/.sub.A) of a tension .sub.B of the coating layer B on the surface side applied to the steel sheet to a tension .sub.A of the coating layer on the steel sheet side A applied to the steel sheet is within a range of 1.20-4.0.