1. Technical Field
The present disclosure generally relates to methods for anodizing and dyeing metallic articles.
2. Description of Related Art
Metallic articles, such as articles made of aluminum/aluminum alloy, magnesium/magnesium alloy, and titanium/titanium alloy, are often anodized for protection, and then dyed or painted for achieving surface appearance requirements. However, this method is able to only provide an uniform singular monochromic color scheme and appearance.
Therefore, there is room for improvement within the art.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or like elements of an embodiment.
Referring also to
In step S101, the workpiece 100 is subjected to one or more pre-anodizing treatments, for smoothing and texturing the decorated surface 10, and removing grease residues or a native oxide layer from the decorated surface 10. The one or more pre-anodizing treatments may include one or more of polishing, texturing, degreasing, alkaline etching, and desmutting. Degreasing is performed using a weak alkaline solution, such as sodium pyrophosphate solution. Alkaline etching is performed using a strong alkaline solution, such as a sodium hydroxide solution. Desmutting is performed using a strong acid solution. Examples of polishing methods that may be used include chemical polishing or mechanical polishing. Examples of texturing that may be used include sandblasting or wiredrawing.
In step S102, the workpiece 100 is anodized in an electrolyte solution 200, such that an anodization layer 20 is formed on the decorated surface 10. The anodization layer 20 is porous by having a plurality of holes 30 therein. During the anodizing treatment, an immersion time of the decorated surface 10 in the electrolyte solution is varied gradually along a predetermined direction, such that the depth of the holes 30 gradually changes along the predetermined direction (referring to
In the illustrated embodiment, referring to
In step S103, the workpiece 100 is colored by a dyeing treatment. In the dyeing treatment step, a coloring agent 40 enters and fills the holes 30, respectively, to dye the decorated surface 10. Because the depth of the holes 30 gradually changes, an amount of the coloring agent 40 that can be contained in the holes 30 thereby varies. Thus, the color of the coloring agent 40 filled in the holes 30 of the workpiece 100 appears in different shades (without noticeable color difference found in between adjacent regions of differing shades) by possessing a continuous color gradient, and the anodization layer 20 is colored with a gradual changing color or color gradient.
In step S104, the workpiece 100 is subjected to a sealing treatment. In the sealing treatment step, the workpiece 100 is immersed in a sealing solution to seal the holes 30, such that the anodization layer 20 has good or sufficient wear resistance. Sealing agents 40 in the sealing solution 200 can be nickel acetate, nickel sulfate, or cobalt sulfate.
In step S 105, the workpiece 100 is heat dried.
In other embodiments, if the workpiece 100 is cleaned or a texturing effect is not needed, step S101 can be omitted. Step S104 can be omitted if a required wear resistance of the workpiece is low. Step S105 can be omitted if desired, and the workpiece can be air dried instead.
Because the decorated surface 10 is not immersed in the electrolyte solution all at once, the depths of the holes 30 after the anodization treatment changes gradually from the first dipped end 60 toward the second dipped end 80 for each workpiece 100, and the amount of the coloring agent 40 received in the holes 30 during the dyeing treatment varies gradually from the first dipped end 60 toward the second dipped end 80. Thus, the color of the coloring agent 40 appears in different shades on the decorated surface 10 without noticeable color difference found in between adjacent portions, and the anodization layer 20 is colored with a gradual changing color or continuous color gradient. The above-described method for anodizing and dyeing a metallic article is easy to control, and thus is suitable for mass production.
In other embodiments, after pre-anodizing treatments, the decorated surface 10 may be anodized in the electrolyte solution 200 in other ways or via other techniques. For example, in a second embodiment (referring to
Depending on the embodiment, some of the steps being described may be removed or eliminated, while other steps may be added, and the sequence of steps may be changed. It is also to be understood that the description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps.
It is to be understood, however, that even through numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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201210077777.9 | Mar 2012 | CN | national |