TWI421371B - Method of anodizing aluminum or aluminum alloy - Google Patents

Description

Aluminium or aluminum alloy surface anode treatment method

The invention relates to an aluminum or aluminum alloy surface anode treatment method.

In order to adapt to the trend of consumers paying attention to metal texture, high-grade products of 3C products such as computers, communications, and consumer electronics are gradually taking metal casings as the mainstream. The metal material has the advantages of good electromagnetic shielding effect, good heat dissipation, good rigidity, impact resistance, and the environmentally-friendly characteristics of recycling.

Aluminum and its alloys have the advantages of light weight, fast heat dissipation and exquisite appearance, and can be selected for bright surface or matte finish according to requirements, so it is suitable for the production of metal casings and their surface patterns. In the application, an oxide film is often formed on the surface by anodizing, and the oxide film can be formed on the surface of the aluminum material with hard wear resistance, high corrosion resistance and beautiful color. The conventional anodizing process for obtaining an oxide film of different colors on the surface of the metal casing is achieved by multiple anode treatments and multiple coloring, wherein each anode treatment is performed by masking on the region of the next anode treatment. Dividing, this method can obtain a multi-color oxide film on the metal surface, but the process is more complicated, and because of the design of the jig for shielding, the design cost is high. At the same time, this method is difficult to make high-precision decorative patterns. Moreover, the oxide film obtained by the method lacks a three-dimensional effect, and it is difficult to obtain different surface effects on the same metal substrate.

In view of this, the present invention provides an anodizing process for obtaining different surface effects on the same aluminum or aluminum alloy substrate.

An aluminum or aluminum alloy surface anodizing method comprising the steps of: providing an aluminum or aluminum alloy substrate, the substrate comprising an inner surface and an outer surface opposite the inner surface; and the first surface of the outer surface of the substrate Processing, the outer surface has a first machined surface effect; the substrate is first anodized to form an oxide film having a first color on the surface of the substrate; and part or all of the substrate is formed on the inner surface of the substrate An oxide film for electrically conducting the substrate; performing a second machining process different from the first machining on the outer surface of the substrate, removing a portion of the oxide film on the outer surface, and having the region of the oxide film removed Two machined surface effects; the substrate is subjected to a second anodization to form an oxide film having a second color different from the first color in the region having the second machined surface effect.

Compared with the prior art, the aluminum or aluminum alloy surface anodizing method of the present invention can obtain different machined surface effects by performing more than one machining process on the surface of the aluminum or aluminum alloy, and then directly on the surface after each machining. Anodizing is carried out and dyed with different colors, thereby obtaining different surface effects having a three-dimensional effect on the same substrate surface. The method does not require a masking fixture specially designed for dividing the anode treatment area The process is simple and the cost is low.

In the preferred embodiment of the present invention, the surface treatment method for the aluminum or aluminum alloy surface is described by taking an anode surface treatment of a metal substrate of aluminum or aluminum alloy as an example, including the following steps:

(1) An aluminum or aluminum alloy substrate is provided, the substrate comprising an inner surface and a surface opposite the inner surface.

(2) performing a first machining treatment on the outer surface of the substrate such that the outer surface has a first machined surface effect. For example, the outer surface of the substrate is sandblasted to give a matte matte finish.

(3) The substrate is subjected to a first anode treatment to form an oxide film on the surface of the substrate. The step comprises first anodizing the substrate at an anode treatment solution of 180-220 g/L sulfuric acid at 19-21 ° C for 45 to 55 minutes at a voltage of 10 to 12 V. The preferred concentration of sulfuric acid is 190-210 g/L. And performing the first coloring treatment on the metal substrate after the first anodization, so that the oxide film formed by the first anodizing treatment has the first color. The first coloring treatment may be adsorption coloring or chemical coloring, and this embodiment is adsorption coloring. Then, the colored substrate is subjected to a sealing treatment in a solution containing a sealing agent to improve the anti-pollution and anti-corrosion properties of the surface oxide film. In this embodiment, the R500 type active agent is selected as the sealing agent, the treatment temperature is 90-100 ° C, and the treatment time is 12-18 minutes. Finally, the substrate is dried at about 60 ° C.

(4) An oxide film partially or entirely formed on the inner surface of the substrate is removed by laser engraving to make the substrate conductive.

(5) performing a second machining process different from the first machining on the outer surface of the substrate, removing a portion of the oxide film on the outer surface, and making the region of the oxide film different from the first machining effect The second machined surface effect. For example, the second machined area exhibits a fine line stripe effect, such as a CD pattern, a sun pattern, etc. similar to the surface texture of the disc.

(6) The substrate is subjected to a second anodizing treatment. The step comprises first anodizing the substrate at an anode treatment solution of 180 to 220 g/L sulfuric acid at 19 to 21 ° C for 28 to 32 minutes at a voltage of 9.5 to 10.5 V. And performing the second coloring treatment on the metal substrate after the second anodization, so that the oxide film formed by the second anodizing treatment has a second color different from the color of the first anodized oxide film. The second coloring treatment may be adsorption coloring or chemical coloring, and this embodiment is adsorption coloring. Then, the colored substrate is subjected to a sealing treatment in a solution containing a sealing agent to improve the anti-pollution and anti-corrosion properties of the surface oxide film. In this embodiment, the SH2 type sealing agent is selected, the processing temperature is 90~100 °C, and the processing time is 12-18 minutes. Finally, the substrate is dried at about 60 ° C to obtain two-color anode surface with two different surface effects on the surface of the aluminum or aluminum alloy substrate.

The substrate is also subjected to an anodizing pretreatment before the first anodizing treatment. The pretreatment comprises: washing the substrate with a solution containing the corresponding metal degreaser, and then subjecting the substrate to a solution containing phosphoric acid and sulfuric acid for chemical polishing, followed by chemical polishing after treatment with a solution containing 20% to 40% nitric acid. The metal substrate is stripped of a black film to remove a black film formed on the surface of the workpiece by the above chemical polishing treatment.

It can be understood that by repeating the above steps (4) to (6), a more surface effect, multi-color anode surface can be obtained on the substrate.

Compared with the prior art, the aluminum or aluminum alloy surface anodizing method of the present invention can obtain different machined surface effects by performing more than one machining process on the surface of the aluminum or aluminum alloy, and then directly on the surface after each machining. Anodizing is carried out and dyed with different colors, thereby obtaining different surface effects having a three-dimensional effect on the same substrate surface. The method does not need to be specially designed for the shielding fixture for dividing the anode treatment area, and the process is simple and the cost is low.

Claims (7)

An aluminum or aluminum alloy surface anodizing method comprising the steps of: providing an aluminum or aluminum alloy substrate, the substrate comprising an inner surface and an outer surface opposite the inner surface; and the first surface of the outer surface of the substrate Processing, the first machining process is sandblasting, so that the outer surface has a matte matte effect; the substrate is subjected to a first anodizing treatment and a coloring treatment to form an oxidation of the first color on the surface of the substrate. a film; an oxide film partially or entirely formed on the inner surface of the substrate is removed by laser engraving to make the substrate conductive; and the outer surface of the substrate is subjected to a second machining process different from the first machining, and the outer surface is removed. a partial oxide film on the surface, and causing the region of the oxide film to exhibit a line stripe effect; the substrate is subjected to a second anodizing treatment and a coloring treatment to form a region different from the second machined surface effect An oxide film of a second color of color. The method for treating anodizing of aluminum or aluminum alloy surface according to claim 1, wherein the first anodizing treatment and the second anodizing electrolyte comprise 180-220 g/L sulfuric acid, and the electrolyte temperature is 19 ° C. 21 ° C. The method for treating anodizing of aluminum or aluminum alloy surface according to claim 1, wherein the first anode treatment voltage is between 10 and 12 V, and the treatment time is 45 to 55 minutes. The method for anodizing aluminum or aluminum alloy surface as described in claim 1, wherein the second anode treatment voltage is between 9.5 and 10.5 V, and the treatment time is 28 to 32 minutes. The method for anodizing aluminum or aluminum alloy surface according to claim 1, wherein the first anodizing treatment and the second anodizing step comprise sealing the formed anodized film. An aluminum or aluminum alloy surface anodizing method as described in claim 1, wherein the coloring method is adsorption coloring. The method for treating an aluminum or aluminum alloy surface according to claim 6, wherein before the first anodizing, the substrate is subjected to an anodizing treatment, the pretreatment comprising: degreasing cleaning, chemical polishing treatment And peeling black film.