SURFACE TREATMENT OF ALUMINUM MATERIAL

PURPOSE:To obtain an Al material provided with high hardness as well as excellent corrosion resistance, electrical insulating characteristic, etc. on the surface by irradiating high-intensity light under the conditions under which an Al material is not melted to the surface of the Al material having a amorphous aluminum layer on the surface thereby changing said amorphous aluminum layer to a crystalline aluminum layer. CONSTITUTION:An Al material is subjected to anodic oxidation in an aq. soln. of, for example, sulfuric acid, oxalic acid, chromic acid, etc. to oxidize the Al on the surface of the Al material and to form the amorphous aluminum film layer. An irradiating spot 3 of high-intensity light is formed to a prescribed size on the surface of, for example, the Al material 4 to be treated as shown in the figure and the spot 3 is scanned at a specified speed in a prescribed direction 5 to irradiate and treat the entire part of the surface of the material 4. As a result the amorphous aluminum layer on the surface of the material 4 is consequently changed to the crystalline aluminum layer and the hardness of the surface is increased to >=1,000Hv. The high corrosion resistance to a strong acir or alkali not possible with the prior art as well as an exceptionally outstanding electrical insulating characteristic are provided to said surface.