PURPOSE: To obtain a film which is dense and thoroughly free from a flaw such as a pinhole by applying the aimed film on the surface of a material to be coated via an Al film having prescribed film thickness and thereafter performing anodic-oxidation treatment thereon.
CONSTITUTION: An Al film 2 having 0.1 - 20μm thickness is applied on the surface of a material 1 to be coated such as a soft steel sheet by a physical vapor deposition method, such as a high-frequency magnetron sputtering. Successively the aimed film 3 such as pure Nb is applied thereon. Then anodic- oxidation treatment is performed to the film 3 in a sulfuric acid bath for a prescribed time. An electrolytic liquid is passed through a pinhole 4 existing in the film 3 and is allowed to penetrate in the surface of the Al film 2 just under the pinhole 4 to form an anodized aluminum layer. The pinhole 4 is buried by the produced anodized aluminum layer 5. In this case, sealing treatment of the anodized aluminum layer 5 obtained after the anodic-oxidation treatment is desirably performed. Thereby the film 3 thoroughly free from a flaw such as the pinhole can be obtained.
ENDO TAKESHI
OHASHI YASUKAZU
FUKUDA MITSUAKI
