JPH01240696A - Anodic oxidation for titanium or titanium alloy - Google Patents

Abstract

PURPOSE:To form a uniform colored film free from irregular color on a titanium material by applying anodic oxidation treatment to a Ti material by the use of this Ti material as an anode, polishing the resulting treated surface, and then applying anodic oxidation treatment to the above again. CONSTITUTION:A titanium or titanium-alloy material is used as an anode and an electric current is sent between this anode and a cathode in an electrolytic solution, by which anodic oxidation treatment is applied to the titanium material. Subsequently, the surface after subjected to the above anodic oxidation treatment is polished and surface characteristics are uniformized, and then, anodic oxidation treatment is applied again to the above. At this time, it is preferable to regulate anodic oxidation voltage in the first anodic oxidation treatment to 3-30V. By this method, the uniform colored film can be formed on the surface of the titanium material by a simplified process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an anodizing method for forming a uniform colored film without inclusions on titanium or titanium alloy material.

[Conventional technology]

JP-A-50-110946 and other publications propose an anodizing method for forming a colored film on the surface of titanium or titanium alloy materials. In this method, a workpiece made of titanium or a titanium alloy material is subjected to pretreatment such as degreasing, pickling, and cleaning of its surface, and then the workpiece is placed on an anode (1) as shown in Figure 2. The anode (1) and cathode (2) are immersed in an electrolyte solution, fixed, and a current is passed between the two electrodes to oxidize the surface of the anode (1).

[Problem that the invention seeks to solve]

In the above methods, the condition of the surface of the anode (1) before oxidation is affected, and depending on the surface condition, inclusions may appear in the colored film, making it impossible to obtain a uniform colored film. many. That is, in the anodizing treatment of titanium or titanium alloy materials, the color can be changed greatly depending on operating conditions such as applied voltage, but on the other hand, there is a drawback that color unevenness is likely to occur due to uneven pickling or degreasing.

The present invention was made in order to solve the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a method of anodizing titanium or titanium alloy materials that can form a uniformly colored film without any single color spots.

[Means for solving problems]

Therefore, the basic feature of the present invention is that titanium or a titanium alloy material is used as an anode, and after anodizing treatment is performed on the material, the treated surface is polished and anodizing treatment is performed again.

In the present invention, the first anodizing treatment and the subsequent polishing serve to make the surface quality of the titanium or titanium alloy material uniform. The subsequent anodic oxidation treatment ultimately plays a role in forming a colored film. These two effects form a uniformly colored film on the titanium or titanium alloy material.

On the other hand, even in the anodizing treatment performed when carrying out the above method, when performing it on a large titanium or titanium alloy material, it is necessary to make the area of the cathode, which is the counter electrode, larger than the area of the anode. be. For this reason, anodizing performed at a constant flow density requires a large power source in the case of large titanium or titanium alloy materials, which limits the size of these workpieces.

Furthermore, even if the cathode area is large, if the contact point with the current-carrying cable is localized at the electrode, embedding due to the localization is likely to occur in a large workpiece.

Therefore, in the second invention, when applying the first invention method to a large titanium or titanium alloy material to uniformly form a colored film, during the first anodizing treatment and the second anodizing treatment, Alternatively, during the second anodizing process, the anode part and/or the cathode part are moved while maintaining a constant electrode gap between the anode part and the cathode part to carry out the anodizing process. There is.

Due to this movement, a colored film is formed on the entire surface of the large titanium or titanium alloy material used as the anode, and since the distance between the anode and cathode is always kept constant during the movement,
The film becomes uniform. Therefore, the cathode may be small, resulting in a corresponding reduction in the current capacity of the power supply.

In addition, in the first anodizing process in both of the above inventions,
It is preferable to set the anodizing voltage to 3 volts or more and 30 volts or less. An oxide film is formed on the surface of the workpiece by the initial hot water oxidation, and the formation of this anodic oxide film helps improve workability and create a uniform surface in the next polishing step. At this time, an oxide film having a constant thickness is formed depending on the applied voltage, but if the applied voltage is greater than 30V, the next polishing process will take a long time and a thick film will be formed. When an oxide film is formed, variations in the oxide film thickness corresponding to the surface texture of the titanium material will be reflected in the surface texture after polishing, and embedding will occur even after the second anodic oxidation treatment. . Further, when the applied voltage is lower than 3V, there is almost no formation of an oxide film, and it does not play a role in making the surface quality of the workpiece uniform. For the above reasons, the applied voltage during the first anodic oxidation was set to 3 V or more and 30 V or less.

〔Example〕

The present invention will be explained below with reference to Examples.

Alkali-degreased titanium plate (10 (Lm(t)
oven (w) x 1 nm (t)) at 25°C
The surface was pickled by immersing it in a mixed aqueous solution of 3E1 hydrofluoric acid and 7 superimposed hydrogen peroxide for 2 minutes, degreased, and washed to prepare a sample for anodizing treatment as shown below.

The above sample was oxidized in a 1% by weight phosphoric acid aqueous solution by applying an anodic oxidation voltage of 30V. After this, polishing was performed to remove the anodic oxide film.

This polishing operation took 10 minutes. Further 1% by weight 1J
An anodic oxidation voltage of 20 V was applied in an aqueous acid solution, and the sample was colored blue. The above processing is referred to as Example 1.

The voltage of the second anodic oxidation treatment in Example 1 was set to 110
The same operation as in the example was carried out except that the color was changed to v, and the sample was colored pink. The processing at this time will be referred to as a second embodiment.

The voltage of the second anodic oxidation treatment in Example 1 was changed to 5 V, and the same operation as in Example 1 was performed except for that, and the sample was colored gold.

The above processing is referred to as a third embodiment.

Similarly, the voltage in the first anodizing treatment in Example 1 was changed to 3 V, and the other operations were the same as in Example 1. Processing in this case will be described as a fourth embodiment.

The above sample was not anodized and polished at a low voltage as in Example 1, but was colored blue by applying an anodic oxidation voltage of 20 V in a 1% by weight IJ acid aqueous solution. The above processing is referred to as conventional example 1.

The voltage of the anodic oxidation treatment in Conventional Example 1 was changed to 110 V, and the other operations were the same as in Conventional Example 1, and the sample was colored pink. The processing at this time will be referred to as Conventional Example 2.

The same procedure as in Conventional Example 1 was carried out except that the voltage of the anodizing treatment in Conventional Example 1 was changed to 5 V, and the sample was colored gold. The above processing is referred to as conventional example 3.

On the other hand, the voltage of the first anodizing treatment in Example 1 was set to 4
The voltage was changed to 0V and polishing was performed.

At this time, it took 30 minutes to remove the anodic oxide film. Other than that, the same operation as in Example 1 was performed. The processing in this case will be taken as a comparative example.

After performing these treatments, as shown in Figure 1, for each part A to F of the sample time, a'' and b*, which represent the hue and saturation, were determined using a color measuring machine in accordance with JIS Z8729. The results shown are obtained.

As is clear from this table, in Examples 1 to 4 in which the method of the present invention was carried out, almost no change in hue and saturation was observed in each part of sample α1. On the other hand, in the case of Conventional Examples 1 to 3 and Comparative Example, some inclusion was observed in each part of sample αQ.

Further, in this experiment, the first invention method was shown as Examples 1 to 4, but the results were the same even if the second invention method was implemented instead. As mentioned above, the method of the second invention is effective for forming a colored film on large titanium plates, etc., and the effect of the second invention becomes more pronounced when using a sample larger than the sample in the above experiment. Needless to say.

Note that, as long as the conditions specified in the present invention are satisfied, colored films can be formed on both sides of a titanium plate, and titanium materials having a cylindrical shape or a pipe shape can also be applied.

〔Effect of the invention〕

According to the method of the present invention described in detail above, a uniform colored film can be formed on the surface of titanium or titanium alloy material by a simple process, and furthermore, according to the second invention, a uniform colored film can be formed even on a large-sized material. It has excellent industrial effects, such as making it possible to form.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing which part of the sample was measured when hue and saturation were measured with a color measuring device in the experiment, and Figure 2 is an explanatory diagram showing the state of implementation when conventional anodizing method was performed. It is a diagram. In the figure (1 indicates the anode, (2) indicates the anode, and (11 indicates the sample). Patent applicant: Nippon Kokan Co., Ltd.

Claims (3)

[Claims] (1) A method for anodizing a titanium or titanium alloy material, which comprises using titanium or a titanium alloy material as an anode and subjecting it to anodizing treatment, polishing the treated surface, and subjecting the material to anodization treatment again. (2) The method of anodizing titanium or titanium alloy material according to claim 1, wherein the anodizing voltage of the first anodizing treatment is 3 volts or more and 30 volts or less. (3) In the anodizing method according to claim 1 or 2, the anode portion and the cathode portion are While maintaining a constant electrode gap between the anode portion and/or
Or an anodizing method for titanium or titanium alloy material, characterized in that the anodizing treatment is performed by moving the cathode part.