JPS5922796B2 - Anode component equipment for aluminum anodizing electrolytic treatment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an aluminum anode used for the purpose of racking, etc., for supporting and energizing the aluminum material to be anodized in the anodizing electrolytic treatment of aluminum (commonly known as alumite treatment). Anode member device for oxidation electrolytic treatment (hereinafter abbreviated as anode member device).

). Generally used for anodizing electrolytic treatment of aluminum.

Pure aluminum or aluminum alloy is mainly used for the anode member device, such as the frame or rack (commonly known as “hitzukake”), but due to the characteristics of aluminum, the aluminum material used for this type of anode member device has the following characteristics. There are various problems such as: In other words, since the anode member device immersed in the electrolyte is made of the same aluminum material as the product to be treated, the part immersed in the electrolyte is anodized together with the product, and an anodic oxide film is generated on the surface. . In other words, since the same amount of current as the product flows out from the surface of the anode member, there is a problem of extremely large power loss. Furthermore, as mentioned above, the anodic oxide film formed on the frame of the anode member is non-conductive, so when reusing this frame, etc., the anodic oxide film must be dissolved and removed in order to obtain an electrical contact. Must be. In actual operation, the anodic oxide film is separately dissolved and removed using an alkaline solution, or the anodic oxide film is removed using these treatment solutions, which also serve as pre-treatment for products, such as alkaline degreasing, etching, or chemical polishing.
In this way, the anode member device made of aluminum gradually wears out as the anodic oxide film is repeatedly generated and dissolved and removed each time the product is processed, so it is necessary to maintain sufficient strength to support the product. Therefore, the cost of the anode member device cannot be ignored in the operating cost. Furthermore, as mentioned above, since chemicals are consumed to remove the anodic oxide film, the cost required for this process increases considerably. On the other hand, titanium materials are also used in some cases as anode member devices for anodic oxidation electrolytic treatment of aluminum.

In this case, the anodic oxide film produced on the surface of the anode member during the anodizing process is extremely thin and easily destroyed by the pressure from the product during racking. Electrical contacts can be obtained without actively dissolving the anodic oxide film. Therefore, titanium consumption is low, so it can be used repeatedly for a long period of time, and the amount of chemicals consumed is also small. Furthermore, the amount of current flowing out from the titanium material during anodizing electrolytic treatment is significantly smaller than that from the aluminum material, and therefore power loss is also significantly smaller. In this way, the anode member device using titanium material has various advantages compared to the anode member device using aluminum material, and it also has much higher strength and springiness than aluminum material, so It is an important material as a racking member for anodizing long aluminum products such as heavy aluminum products or aluminum sashes, and as an anode member for high current density anodic oxidation. However, although titanium material anode members have a small amount of wear, when they are used frequently, they frequently break due to racking, and this is a problem when using titanium material for anode member devices.

For example, when anodizing aluminum sashes, titanium racks are used due to strength requirements, and titanium bolts are used to fasten various parts of the titanium racks, but accidents involving bolt breakage are quite common. Therefore, there is a problem in that work efficiency is significantly reduced due to replacement and maintenance of broken parts. In addition, even if breakage does not occur, failure of the threads of titanium bolts or the threads of titanium parts on the female thread side may cause electrical contact failure, resulting in uneven product quality, such as uneven anodic oxide coating. may have an adverse effect on the As a result of repeated investigations and studies by the inventors of the present invention into the causes of such breakage accidents of titanium materials, it was found that the cause of such breakage accidents of titanium materials was due to environmental corrosion (mainly corrosion in a reducing atmosphere caused by sulfuric acid electrolytic treatment solution) during a series of steps of anodizing treatment. It was found that embrittlement due to hydrogen absorption was the main cause. Based on the above circumstances, we conducted repeated research to find a new material that could solve the problems of titanium as an anode component device, and found that metal zirconium, which had not been considered at all for an anode component device, solved the problems of titanium material. In other words, it was discovered that metal zirconium has extremely good corrosion resistance against sulfuric acid and little hydrogen embrittlement, so there is little risk of breakage accidents. It was discovered that the properties are equal to or better than those of titanium, which led to the creation of this invention. That is, the anode member device of the present invention is characterized in that it is constructed using a material made of metallic zirconium.

This invention will be explained in more detail below.

First, the corrosion resistance of metallic zirconium used in the anode member device of the present invention and titanium used in the conventional anode member device will be compared and explained.

Corrosion resistance against a treatment solution (alumite treatment solution) during anodic oxidation electrolysis was tested. Here, the processing solution was heated to 15°C at 20°C.
%H2SO, and the weight loss was measured after 30 minutes of constant potential electrolysis at 20V, and the degree of erosion was calculated from the weight loss. The results are shown in Table 1 below. Furthermore, when the corrosion resistance against sulfuric acid itself was tested, the results shown in Table 2 below were obtained.

Here, 10% H2SO4 at 70°C was used as the sulfuric acid.
The samples were immersed in this solution for 5.5 hours, and the weight loss, degree of corrosion, and degree of erosion were determined. These results revealed that zirconium has much higher corrosion resistance than titanium against the sulfuric acid treatment solution during electrolytic treatment, and also has much higher corrosion resistance against sulfuric acid itself.

Therefore, it is clear that hydrogen embrittlement is suppressed in the anode member device using metallic zirconium, and there is almost no risk of breakage. Next, during the anodization process, we measured the current flowing out from the zirconium anode member as well as the current flowing out from the titanium and aluminum anode members, and the results shown in Figure 1 and Table 3 were obtained. It was done.

Here, 15% H, SO4 at 20° C. was used as the treatment liquid, and 20V constant potential electrolysis was performed. From this result, it is clear that the current flowing out of the zirconium anode member during anodization treatment is much lower than that of the aluminum anode member, and even compared to the titanium anode member. be.

Therefore, if an anode member made of zirconium is used, power loss will be much smaller than if an anode member made of titanium is used. Furthermore, to explain other characteristics as an anode member, when zirconium material is anodized, an anodic oxide film is generated on the surface like titanium.
This oxide film is extremely thin (usually about a few hundred amperes)
Therefore, when aluminum products are racked, they are easily destroyed by the pressure, so there is no need to perform treatment to remove the anodic oxide film when reusing them, and therefore the zirconium material is not consumed. Can be used repeatedly for a long period of time. In addition, since zirconium has mechanical strength comparable to titanium, zirconium anode member devices can be used for anodizing heavy or long aluminum products in the same way as titanium anode member devices. . The shape of the anode member device of the present invention is arbitrary, as long as it is in the shape of a frame or a rack that has the function of supporting a product to be processed, such as an aluminum product, and functioning as an electrical contact.

As is clear from the above description, the anode member device of the present invention does not have the risk of breakage that occurs with titanium anode member devices, and has significantly less power loss than titanium ones. This is practically negligible, and its other properties as an anode member are comparable to or better than those made of titanium, making it useful for anodizing aluminum.

Examples of this invention are described below.

EXAMPLE As shown in FIG. 2, a frame-shaped anode member device is made using a metal zirconium bar 1, and an aluminum product 2 is attached to the aluminum wire 3.
- Anodization electrolytic treatment was performed using 15% H2SO4 at 20°C as an electrolyte.

When we measured the change in bath voltage over time at a current density of 1.5 A/Dwl, the bath voltage shifted from 15 V to 20 V from the beginning of electrolysis to the end, but there was no significant change in bath voltage during that time, and there was no racking. I repeated the test by changing the position, but no contact failure was observed. Furthermore, there was very little variation in the anodic oxide film among the plurality of aluminum products racked onto one anode member.

[Brief explanation of the drawing]

FIG. 1 is a graph showing changes in anode outflow current over time for an anode member using zirconium and an anode member using titanium, and FIG. 2 is a perspective view showing the shape of an anode member device according to an embodiment of the present invention.

Claims (1)

[Claims] 1. An anode member device for aluminum anodizing electrolytic treatment, characterized in that it is constructed using a material made of metallic zirconium.