| 摘要 |
PROBLEM TO BE SOLVED: To increase the adhesion of a coating film to a base material 19 made of an Al alloy.SOLUTION: Provided is a method for treating the surface of a base material made of an Al alloy, including: an alkali etching step of contacting the surface of the base material 19 made of an Al alloy with an etchant for a prescribed time; a step in which the surface contacted with the etchant is water-washed and is dried; and a step in which a coating film is formed on the surface after that, and the alkali etching is controlled in such a manner that surface roughness Rz after the drying step reaches 12.8 μm or more and also apparent contact angle with water reaches 30° or lower. |
