Annealing separating agent composition for grain-oriented electrical steel sheet, grain-oriented electrical steel sheet, and method for manufacturing grain oriented electrical steel sheet

1. A grain-oriented electrical steel sheet, comprising:

a grain-oriented electrical steel sheet substrate; and

a Monticellite coating formed on one side or both sides of the grain-oriented electrical steel sheet substrate;

wherein the Monticellite coating includes Ca in an amount of 0.5 to 90% by weight, Mg in an amount of 3 to 80% by weight, Si in an amount of 3 to 80% weight, O in an amount of 3 to 80% by weight, and Fe in a balance.

2. The grain-oriented electrical steel sheet according to claim 1 ,

wherein the Monticellite coating has a thickness of 0.1 to 10 μm.

3. The grain-oriented electrical steel sheet according to claim 1 ,

wherein a ceramic layer is further formed on the Monticellite coating.

4. The grain-oriented electrical steel sheet according to claim 3 ,

wherein the ceramic layer comprises a ceramic powder.

5. The grain-oriented electrical steel sheet according to claim 4 ,

wherein the ceramic powder is at least one selected from the group consisting of Al 2 O 3 , SiO 2 , TiO 2 , ZrO 2 , Al 2 O 3 , TiO 2 , Y 2 O 3 , 9Al 2 O 3 .2B 2 O 3 , BN, CrN, BaTiO 3 , SiC, and TiC.

6. The grain-oriented electrical steel sheet according to claim 4 ,

wherein the ceramic layer further comprises a metal phosphate.

7. The grain-oriented electrical steel sheet according to claim 6 ,

wherein the metal phosphate comprises at least one selected from Mg, Ca, Ba, Sr, Zn, Al, and Mn.

8. The grain-oriented electrical steel sheet according to claim 1 ,

wherein the grain-oriented electrical steel sheet substrate comprises silicon (Si): 2.8 to 6.8 wt. %, aluminum (Al): 0.020 to 0.040 wt. %, manganese (Mn): 0.01 to 0.20 wt. %, and antimony (Sb), tin (Sn), or a combination of Sb and Sn in an amount of 0.01 to 0.15 wt. %, Fe and other unavoidable impurities in a balance.

9. A manufacturing method of the grain-oriented electrical steel sheet of claim 1 comprising:

preparing a steel slab;

heating the steel slab;

hot-rolling the heated steel slab to produce a hot-roped steel sheet; cold-rolling the hot-rolled sheet to produce a cold-rolled sheet; decarburizing annealing and nitriding annealing the cod roiled sheet;

applying an annealing separating agent on the surface of the decarburizing annealed and nitriding annealed steel sheet; and

high-temperature annealing the steel sheet applied with the annealing separating agent to form the Monticellite coating,

wherein the annealing separating agent comprises, based on a solid content, 30 to 70% by weight of a calcium compound, and magnesium oxide or magnesium hydroxide in a balance, thereby producing the grain-oriented electrical steel sheet according claim 1 .

10. The manufacturing method of a grain-oriented electrical steel sheet according to claim 9 ,

further comprising a step of forming a ceramic layer on the Monticellite coating after the high-temperature annealing.

11. The manufacturing method of a grain-oriented electrical steel sheet according to claim 10 ,

wherein the step of forming the ceramic layer is a step of forming a ceramic layer by spraying a ceramic powder onto the Monticellite coating.

12. The manufacturing method of a grain-oriented electrical steel sheet according to claim 10 ,

wherein the step of forming the ceramic layer is a step of forming a ceramic layer by applying a composition for forming a ceramic layer comprising a ceramic powder and a metal phosphate on the Monticellite coating.

13. The manufacturing method of a grain-oriented electrical steel sheet according to claim 12 ,

wherein the step of decarburization annealing and nitriding annealing the cold-rolled sheet is a step of decarburization annealing and nitriding annealing the cold-rolled sheet simultaneously, or nitriding annealing the cold-rolled sheet after decarburization annealing.