Patent Number: 
Section: claims

1. A corrosion-resistant structure for a high-temperature water system comprising:a structural material; anda corrosion-resistant film consisting of at least one chemical compound selected from the group consisting of La2(CO3)3, La(CH3COO)3 and La2(C2O4)3, deposited on a surface in a side that comes in contact with a cooling water having a temperature of 20° C. or higher and 350° C. or lower, of the structural material which constitutes the high-temperature water system that passes a cooling water of high temperature therein. 2. The corrosion-resistant structure for the high-temperature water system according to claim 1, wherein the structural material is at least one structural material selected from the group consisting of a carbon steel, a copper alloy and a Ni-based alloy. 3. The corrosion-resistant structure for the high-temperature water system according to claim 1, wherein a deposition amount of the at least one chemical compound is 1 μg/cm2 or more and 200 μg/cm2 or less. 4. The corrosion-resistant structure for the high-temperature water system according to claim 1, wherein an oxide film of the structural material is formed on a surface of the structural material, and the corrosion-resistant film is formed on a surface of the oxide film. 5. The corrosion-resistant structure of claim 1, wherein the corrosion-resistant film consists of La2(CO3)3. 6. The corrosion-resistant structure of claim 1, wherein the corrosion-resistant film consists of La(CH3COO)3. 7. The corrosion-resistant structure of claim 1, wherein the corrosion-resistant film consists of La2(C2O4)3. 8. The corrosion-resistant structure of claim 1, wherein the structural material is a carbon steel surface and the corrosion-resistant film is a uniform and continuous film covering the surface of the carbon steel. 9. The corrosion-resistant structure of claim 8, further comprising:an oxide film between the surface of the carbon steel and the corrosion-resistant film. 10. The corrosion-resistant structure of claim 1, wherein the corrosion-resistant film consists of at least one chemical compound in an amount of 20 μg/cm2 to 120 μg/cm2.