Processing method of creating rainbow color, method of manufacturing article which presents rainbow-colored reflective luster, and article which presents rainbow-coloured reflective luster

摘要

The present invention relates to a method of processing an article to be processed so as to cause the article to create rainbow color and a method of manufacturing an article made of aluminum or its alloy which presents rainbow-colored reflective luster. An aluminum plate is prepared as a substrate (2) of an article (1) to be processed. A nickel-phosphorus alloy deposit (3) is formed on the surface of this aluminum substrate (2) by an electroless plating method. Subsequently, this article is heat-treated at the temperature of 150 to 600° C. for 5 seconds to 1 hour in an air atmosphere. Subsequently, pulsed laser light (10) is irradiated onto the surface of the deposit (3). Be performing the aforementioned steps, diffraction gratings (5) which present beautiful rainbow-colored reflective luster can be assuredly formed in the surface of article (1). Furthermore, the processing speed can be further increased.