JP2000248375A - Method for chemical conversion treatment of black film for light-shielding of optical parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the hindrance of the growth of a crystal film by executing film forming treatment in a state in which the flow of a soln. of a chemical conversion treatment agent is stopped. SOLUTION: The bottom of an outer container 2 is provided with a heater 3, and a treating agent 5 for blackening in an outer container 2 is subjected to controlled heating. The supporting board 4 at the inside of the outer container 2 is mounted with the object 1 to be treated, and the treating agent 5 is filled by the amt. by which the soln. surface is made higher than the object 1 to be treated and the inner container 6. Since the treatment is executed only by heating by a heater 3 without executing the forced circulation and oscillation of the treating agent 5 by a circulating pump, the convection of the treating agent by the heating is cut-off by the inner container 6, and the agent flows only at the outside of the inner container 6. As a result, the flow of the soln. by the convection does not directly strike against the object 1 to be treated, so that the crystals of copper oxide sufficiently grow, and a completely black crystal film of copper oxide can be obtd., which grows into a velvet-like film and is formed into a matting state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical conversion method for growing a velvet-like copper oxide crystal film on copper or a copper alloy used mainly for metal optical parts or the like on which optical elements such as lenses are mounted. Regarding the processing method.

[0002]

2. Description of the Related Art In a chemical treatment in which a velvet-like copper oxide crystal film is grown on copper or a copper alloy to obtain a matte black appearance, an object to be treated made of copper or a copper alloy is used as a chemical treatment agent. It is treated by immersion.

Generally, in plating and chemical conversion treatments, a treatment agent is brought into sufficient contact with an object to be treated.
As described in Japanese Patent No. 59, processing is performed while circulating a processing agent in a processing tank using a pump. When a pump is not used, the processing is performed while the object to be processed is rocked in the processing agent. Furthermore, as described in Japanese Patent Application Laid-Open No. H5-112898, a bubble generating tube having a large number of pores may be provided at the bottom of the processing tank, and the processing agent may be stirred by bubbles generated from the bubble generating tube. It has been done.

In the chemical conversion treatment, the treatment agent is heated to a high temperature of 80 ° C. or more, so that convection due to heat can be reduced without forcibly circulating the treatment agent using a pump or swinging the object to be treated. This causes the treatment agent to flow in the treatment tank to promote the reaction.

As described above, in the chemical conversion treatment, it is known that a new chemical agent is constantly brought into contact with an object to be treated by moving the chemical agent by some means, and a good chemical conversion film is formed by this contact. For this reason, also in the chemical conversion treatment for growing the crystal film of copper oxide, in the past, forcible circulation of the treatment agent and rocking of the object to be treated were performed.

[0006]

However, in the chemical conversion treatment method for growing a velvet-like copper oxide crystal film, the treatment agent is circulated or the object to be processed is vigorously agitated as in the prior art. The present inventor has found that contacting a treatment agent with an object to be treated hinders crystal growth because the tip of a growing crystal is scraped off by the treatment agent. As a result, there is a problem that it is not possible to obtain a good light-shielding property by a crystal film grown in a good velvet shape.

Further, even when the treatment agent is heated at a high temperature of 80 ° C. or more without circulating the treatment agent or oscillating the object to be treated, the treatment agent has a convection in the treatment tank. In the same manner as described above, the portion (surface) where the treating agent comes into direct contact with the treating agent is caused to hinder the growth of the crystal film of the copper oxide, thereby causing a problem that a good chemical conversion film cannot be obtained. I have.

The present invention has been made in view of the above problems, and has as its object to provide a method for preventing the growth of a crystal film in a chemical conversion treatment for growing a crystal film of copper oxide. .

[0009]

In order to achieve the above object, the invention according to claim 1 provides a matte by growing a velvet-like copper oxide crystal film on a workpiece made of copper or a copper alloy. In a chemical conversion treatment method for forming a black film having a black appearance and having a light-shielding property, the film formation treatment is carried out in a state where the liquid flow of the chemical conversion treatment agent is stopped.

According to the present invention, the reaction proceeds without inhibiting the growth of the copper oxide crystal by stopping the liquid flow of the chemical conversion treating agent. Therefore, the velvet-like copper oxide is formed on the copper or copper alloy. Crystal film grows regularly, and a matte black film can be formed without unevenness on the entire surface of the object to be treated. For this reason, a black film having high light-shielding properties can be obtained, and it can be applied particularly favorably when the object to be processed is an optical component for mounting an optical element such as a lens or a prism.

According to a second aspect of the present invention, in the first aspect of the invention, in the process of forming a film, the object to be processed is surrounded by a shielding plate.

In the present invention, the use of the shielding plate eliminates the influence of the convection of the liquid due to the heating of the treating agent even in the chemical conversion treatment step in which the treating agent is treated with a high-temperature treating agent. For this reason, a matt black film can be formed on the entire surface of the object to be processed without unevenness.

In the shielding plate surrounding the object to be treated, the processing agent deteriorated with the progress of the processing may stay inside the shielding plate and the reaction may not be promoted. , So that the processing agent can enter and exit slightly,
A shielding plate having an opening on the side opposite to the direction of convection generated by heating the treatment agent may be used.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a process chart for forming a velvet-like black copper oxide film on the surface of a workpiece by subjecting the workpiece to a chemical conversion treatment in this embodiment. As the object to be processed, pure copper, a copper alloy or a copper-plated object is used. In this embodiment, a brass part which is a copper alloy is used. This brass part has an outer diameter (φ) of 30 mm,
It is formed into a cylindrical shape having a thickness of 3 mm.

The alkaline degreasing step is for removing cutting oil adhering to the object to be treated, and using Gospel Dash 5000 (trade name; manufactured by Gospel Kako Co., Ltd.) which is a strongly alkaline degreasing agent Degreasing is performed by heating at ℃. After the degreasing, the object to be treated is washed with water to remove the degreasing agent, and then subjected to a dezincing treatment. The dezincing treatment is a treatment for making the surface of the object to be copper-rich, and as the activator, an Ebonol BA solution (trade name; manufactured by Meltex Co., Ltd.) was used at 95 ° C.

After the dezincing treatment, the substrate is washed with water and subjected to an ebonol treatment for blackening the surface of the object to be processed, and copper oxide crystals grow on the surface of the object. Ebonol C specialty solution A and solution B (trade name; manufactured by Meltex Co., Ltd.) were used as the treating agent for the ebonol treatment, and these were mixed to obtain 9%.
Used at 5 ° C. After this ebonol treatment, the substrate is washed twice with water, dried, and the treatment is completed. Table 1 shows the conditions of the above processing.

[0017]

[Table 1]

FIGS. 2 to 6 show the respective processing methods for subjecting the object 1 made of brass of the above-described size and shape to blackening treatment. In these figures, a heater 3 is provided on the bottom surface of the outer container 2, and the treatment agent 5 for the black dyeing treatment filled in the outer container 2 is controlled and heated so as to maintain 95 ° C. A support plate 4 made of a wire mesh is stretched inside the outer container 2, and the object to be processed 1 is placed on the support plate 4 with the opening thereof facing up and down. The processing agent 5 is filled in such an amount that the liquid level is higher than that of the object 1 and the inner container 6 shown in FIG.

In the processing shown in FIGS. 2 and 3, the circulating pump 7 is connected to the outer container 2. In FIG. 2, the processing is performed while the processing agent 5 is forcibly circulated in the outer container 2 by driving the circulation pump 7. On the other hand, in FIG. 3, the circulation pump 7 is stopped, so that the treatment agent 5 does not circulate forcibly, but circulates by convection generated by heating of the heater 3.

In the processing shown in FIGS. 4 and 5, a car 8 formed by a wire mesh is used, and the object 1 is accommodated in the car 8 in an upright state. Since the basket 8 is formed of a wire mesh, the treatment agent 5 can be circulated inside. The car 8 has a handle 9 for suspension.

In FIG. 4, the processing is performed while the car 8 is rocked via the handle 9 in a state where the object 1 is accommodated. On the other hand, in FIG. 5, the processing is performed in a state where the car 8 is left standing without swinging via the handle 9, and the processing agent 5 is operated by the convection generated by the heating of the heater 3. Circulate in 8.

In the processing shown in FIG. 6, processing is performed using the inner container 6. FIG. 7 shows a state using the inner container 6,
The inner container 6 has five surfaces, that is, a rectangular plate-like bottom surface 6a and four side surfaces 6b rising from four sides of the bottom surface 6a, and the upper surface is open. The bottom surface 6a and the four side surfaces 6b are each formed by a shielding plate made of a stainless steel plate, and the object 1 to be processed is surrounded by five shielding plates 6a and 6b.
Is accommodated and the processing is performed.

In the processing shown in FIG. 6, the processing is performed only by heating by the heater 3 without forcibly circulating the processing agent 5 by the circulating pump as shown in FIG. is there. For this reason, the convection of the treatment agent 5 due to the heating of the heater 3 is blocked by the inner container 6 and only flows outside the inner container 6, as indicated by the arrow in FIG.

The treatment was performed according to FIGS. 2 to 6 to confirm the state of formation of the chemical conversion film (copper oxide). Table 2 shows the results. No. 1 is a process of FIG. No. 2 stops the circulation pump 7 and performs the process of FIG. FIG. 4 shows swinging of the basket 3
No. processing, No. 4 is the process of FIG. Reference numeral 5 denotes the processing in FIG.

The formation of the chemical conversion film was confirmed by checking the color of the film under a white fluorescent lamp. If the copper oxide film is not sufficiently grown, a matte black film cannot be obtained, and the film becomes a brownish and glossy film.If the copper oxide film is sufficiently grown, Is a black copper oxide crystal coating on the entire surface, which grows in a velvety shape and becomes matt.

[0026]

[Table 2]

When the treatment agent 5 is circulated by the circulation pump 7 (No. 1), the entire surface is reddish brown,
This indicates that copper oxide crystals have not grown. When the circulation pump 7 was stopped (No. 2), the degree of reddish brown was smaller than that when the circulation pump 7 was circulated, and although the growth of copper oxide crystals was observed, the convection of the treatment agent 5 due to heating (95 ° C.) caused the outer vessel 2 The bottom surface of the object 1 to be processed, which was generated from the bottom surface toward the liquid surface and directly hit by the convection of the processing agent 5, was in a red-brown state.

When the object 1 is swung (No. 3)
Has a reddish-brown color on the entire surface, and inhibits the growth of copper oxide crystals. Also, when the robot is left standing without swinging (N
o. In 4), growth of copper oxide crystals on the outer periphery and upper surface of the object 1 was observed, and a black film was formed, but convection of the processing solution due to heating occurred from the bottom surface of the outer container 2 toward the liquid surface. As a result, the bottom surface of the object 1 to which the convection of the treatment agent 5 was directly applied was in a red-brown state.

In the case where the circulation of the treating agent 5 by the circulation pump 7 is stopped and the object 1 is treated by being left standing in the inner container 6 (No. 5), the convection of the treating agent 5 by heating causes the liquid to flow. Since the flow does not directly hit the workpiece 1, a black copper oxide crystal film is obtained on the entire surface, which grows in a velvety and matte state, and the copper oxide crystal grows sufficiently. It was confirmed that.

FIG. 8 is a schematic view of copper oxide grown by the chemical conversion treatment. (A) is a case where there is no forced circulation of the treatment agent, no swinging of the object to be treated, and no convection of the treatment agent due to heating. be able to. On the other hand, (b) shows a case where a liquid flow is generated in the processing agent due to forced circulation, oscillation, and convection. In a portion C2 where the liquid flow R of the processing agent is applied, crystal growth of copper oxide is inhibited. For this reason, it is lower than other portions where the liquid flow does not hit.

FIG. 9 shows the result of confirming the surface of the object to be treated after the chemical conversion treatment by an electron microscope. 5 shows the surface after the treatment of No. 5, and FIG.
1 shows the surface after treatment. It can be seen that the copper oxide crystals are uneven in (b), whereas the copper oxide crystals are dense in (a). Therefore, in (a),
It has a matte black appearance and is a chemical conversion coating having the necessary light-shielding properties.

FIGS. 10 to 12 show other forms of the shielding plate surrounding the object 1 to be processed. The shielding plate 20 has an opening 21 formed therein. The opening 21 can be formed by pressing the shielding plate 20, as shown in FIG. In this case, the opening 21 is preferably formed so as to open in the downstream direction of the flow of the processing agent 5 by convection, as indicated by the arrow in FIG.

By forming the opening 21 in the shielding plate 20 in this manner, the treatment agent 5 can enter and exit through the opening 21. For this reason, it is possible to prevent the concentration of the processing agent 5 inside the enclosure surrounded by the shielding plate 20 from changing, and prevent the reaction from being accelerated due to the deterioration of the processing agent 5. When this embodiment is applied to the inner container 6 of FIG. 7, it may be provided on at least one surface of the inner container 6, and preferably on two opposing surfaces.

[0034]

As described above, according to the first aspect of the present invention, the flow of the chemical conversion treatment agent is stopped.
The reaction proceeds without inhibiting the growth of copper oxide crystals. For this reason, a velvet-like copper oxide crystal film grows regularly on copper or a copper alloy, and can form a matte black film without unevenness on the entire surface of the object to be processed, and has high light-shielding properties. A black film can be obtained.

According to the second aspect of the present invention, since the shielding plate is used, the influence of the convection of the liquid due to the heating of the processing agent is eliminated.
A matte black film can be formed without unevenness on the entire surface of the object to be processed.

[Brief description of the drawings]

FIG. 1 is a flowchart showing steps of an embodiment of the present invention.

FIG. 2 is a cross-sectional view in the case where processing is performed by forcibly circulating a processing agent.

FIG. 3 is a cross-sectional view when a treatment agent is treated by convection by heating.

FIG. 4 is a cross-sectional view of a case where an object is processed by swinging.

FIG. 5 is a cross-sectional view when a treatment agent is treated by convection by heating.

FIG. 6 is a cross-sectional view in a case where an object to be processed is processed by being surrounded by a shielding plate.

FIG. 7 is a perspective view of a main part of FIG. 6;

FIGS. 8A and 8B are schematic diagrams showing the growth of copper oxide on the surface of a workpiece.

FIGS. 9A and 9B are front views of a surface state of an object to be processed by an electron microscope after the processing.

FIG. 10 is a front view of a shield plate provided with an opening.

FIG. 11 is a sectional view taken along line AA of FIG. 10;

FIG. 12 is a side view showing the direction of the opening with respect to the flow of the processing agent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing object 5 Processing agent 6 Inner container 20 Shield plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Katsura Imamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo F-term in Olympus Optical Co., Ltd. (Reference) 2K009 AA12 BB06 CC03 DD12 4K026 AA06 BA08 BB01 DA04 EA08 EA09

Claims (2)

[Claims] A velvet-like copper oxide crystal film is grown on an object to be processed made of copper or a copper alloy to form a matte black film and a light-shielding black film. A chemical conversion treatment method for a black coating for shading optical parts, wherein the coating formation treatment is performed in a state where the liquid flow of the chemical conversion treatment agent is stopped. 2. The chemical conversion treatment method for a light-shielding black film for optical parts according to claim 1, wherein, during the growth process of the crystal film, the object to be processed is surrounded by a shielding plate.