Patent ID: 7938950
Filing Date: 2011-05-10
Classification: C09D,C23C,C25D,Y02T,Y10T

Abstract:
1. A method of treating surfaces of a steel plate by forming an inorganic film on the surfaces of the steel plate by cathodic electrolytic treatment in an aqueous solution containing Zr and F and not containing phosphoric acid ions, wherein said inorganic film comprises Zr, O, F and H, contains O and Zr in an uppermost surface of the inorganic surface-treating layer at an atomic ratio of 1<O/Zr <5, contains F and Zr in the uppermost surface of the inorganic film at an atomic ratio of 0.5<F/Zr <2.0, and a coating weight of Zr of the inorganic film being 5 to 100 mg/m 2 .