Patent ID: 8877348

Claim:
A surface-treated steel sheet comprising: an oxygen-containing adhesive layer having a thickness of 20 to 800 nm and which is disposed on at least one surface of the steel sheet and which contains Ti and at least one selected from the group consisting of Co, Fe, Ni, V, Cu, Mn, and Zn, a ratio of the total amount of Co, Fe, Ni, V, Cu, Mn, and Zn to the amount of Ti contained therein being 0.01 to ten on a mass basis, the adhesive layer having been obtained by cathodically electrolyzing in an aqueous solution, and the adhesive layer has bumps arranged with an area density of 16 or more per μm 2 and the area density of the bumps of the adhesive layer is defined as a number of the bumps that are 0.005 μm or more higher than an average line of the bumps and recessed portions, the average line being determined from a SEM image of the layer observed with a scanning electron microscope (SEM) that is three-dimensionally analyzed and filtered at a cut-off wavelength of 1.0 μm.