JPH0280581A - Base material having black body film and production of base material fitted with black body film thereof - Google Patents

Abstract

PURPOSE:To form a specified black body film by forming the black body film made of Ni/P alloy on a base material and making it a black body by etching treatment due to a nitric acid aq. soln. CONSTITUTION:A base material made of a copper plate is degreased, washed with water and thereafter pickled. After nickel strike plating is performed, the base material is immersed in electroless Ni/P alloy plating liquid for a black body film for a prescribed time and thereby an Ni/P alloy plating film is deposited on the surface of the base plate. The base material made of Cu on which the Ni/P alloy plating film has been formed in such a way is washed with water. Then in order to make this alloy film a black body, this alloy film is etched with a nitric acid aq. soln., washed with water and dried. As a result, many conical holes mainly having 1-6mum hole diameter of an aperture part are adjacently formed on the surface. The base material having a black body film which has 0.04-0.1% low whole reflectivity in 320-2200nm wavelength region and is stable and excellent in mechanical vibration and friction and also resistance to moisture, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a substrate having an optical black body film and a method for producing the film.

The optical blackbody film of the present invention has a low total reflectance and is formed on the surface of a base material such as metal, ceramics, glass, or plastics. The method for forming it is to plate a nickel-phosphorus alloy film on the surface of the substrate using a nickel-phosphorus alloy plating solution for blackbody films invented by the inventors, and then to etch this alloy film with a specific chemical substance. It is formed by applying The optical blackbody film of the present invention has a low total reflectance, and its wavelength dependence is also extremely small. From this, it is possible to realize an ideal blackbody film, which can be used in the light receiving part of optical calorimeters, the termination element system of optical transmission systems, optical waveguides, etc.
It can be effectively used for the inner surface of optical connectors, etc.

[Conventional technology] Conventionally, black coatings include coatings using black paint, black surface oxides, coatings of metal compounds, black chromate by electroplating, black nickel coatings, and porous films formed by anodic oxidation. There was a black film containing black dye. However, these black films have a total reflectance of 3 to 1.
0% and high wavelength dependence, making it unsatisfactory for use as a light receiving section of a photocalorimeter.

On the other hand, a film with a lower total reflectance than the above-mentioned film is a completely black film produced by a vapor deposition oxidation method. The total black film has a total reflectance of approximately 0.
At 5%, it is much lower than the above-mentioned all-black paint, etc., and is used as the light receiving part of optical calorimeters.

In addition, U.S. Patent No. 4,233.107 (corresponding patent: JP-A-57-114655), invented by C.E., Johnson, Sr. A black film obtained by the treatment and a method for producing the same are disclosed.

A similar invention is also disclosed in US Pat. No. 4,381.830 by the same inventor. This technology is
, L. Greenlin, U.S. Pat. No. 4.5.
No. 11.614.

[Problem to be solved by the invention] The function of completely absorbing light without reflecting it, such as the light receiving part of a photocalorimeter or the terminal element of an optical transmission system, has many practical uses, and ideal light absorption is required. body (also called black body) is desired.

Regarding the function of simply absorbing light, total blackness formed by ultrafine gold particles has been known for a long time.

For example, total black, which is conventionally used for optical power measurement, has a low total reflectance and is therefore used as a black photoreceptor. However, the problem with all black is that it easily flakes off due to mechanical vibration or friction, absorbs moisture under high humidity conditions, increases total reflectance, and does not recover to its original reflectance even when dry. There are many practical difficulties.

Also, U.S. Pat. No. 4,233,107 and 4.3
The black film disclosed in G1,830 has a total reflectance of 0.5 to 1.0% and is highly practical in that it has high film strength. However, the total reflectance is wavelength dependent, and there are still problems in using it as a photoreceptor for measuring optical power with high precision in a wide wavelength band of 320 to 2200 ng.

Furthermore, the technology disclosed in U.S. Patent No. 4,511,814 is composed of a base material with a two-layer structure in which two layers with different concentrations of phosphorus in the nickel-phosphorous coating are stacked. has been done. Therefore, the number of manufacturing steps is increased, and the total reflectance is higher than the above two inventions.

The purpose of the present invention is to firstly use metals, ceramics, glass,
The total reflectance of light is low on the surface of base materials such as plastics,
It is an object of the present invention to provide a light-absorbing substrate on which a black body film with small wavelength dependence and excellent mechanical strength and moisture resistance is formed, and a method for forming a black body film therefor.

The second object is to provide a base material having a practical black body coating that has better mechanical strength than full black and is therefore not easily damaged.

Thirdly, it is an object of the present invention to provide a base material having a practical blackbody film that has better total reflectance and wavelength-dependent characteristics of total reflectance than either of the above two prior art inventions.

The fourth object is to provide a base material having a practical black body film that can be manufactured without increasing the number of steps as in the invention disclosed by Greerin.

[Means for Solving the Problems] In order to achieve these objects, the present invention provides a black body film that has low total reflectance and small wavelength dependence when etched with a nitric acid aqueous solution. , As an electroless nickel-phosphorus alloy plating solution for black body film, (1) Nickel salt, sodium phosphinate, D, L-
Malic acid or its salt, succinic acid or its salt bath, or (2) nickel salt, sodium phosphinate, D, L-
Two types of nickel-phosphorus alloy plating solutions were used: malic acid or its salt, lactic acid or its salt, and malonic acid or its salt.

This plating solution was determined through experiments by the inventor.

In this invention, metals, glass, ceramics, plastics, etc. are used as the base material on which the black body film is formed.

First, a nickel-phosphorus alloy plating film is applied to the base material using a nickel-phosphorus alloy plating solution for black body film.

An electroless plating method is used for this plating.

If the base material is metal, it is degreased with 1,1.1-trichloroethane and an alkaline degreasing solution, then pickled, followed by nickel strike plating, and then immersed in an electroless nickel-phosphorus alloy plating solution for black body coating. A nickel-phosphorus alloy film having a phosphorus concentration of 7 to 10% is formed on the surface of the substrate.

When the base material is an electrically nonconducting material such as glass, ceramics, or plastics, the surface is activated with a tin chloride solution and a palladium chloride solution, and then an electroless nickel-phosphorous plating solution for black body coating is applied. A nickel-phosphorus alloy film is formed.

For electroless nickel-phosphorus alloy plating for blackbody film, the plating solution is (1) 0.11 to 0.0% of nickel sulfate as nickel salt.
20M As a reducing agent, sodium phosphinate 0.24-0.
36M oxycarboxylic acid, D, L malic acid 0.4-0.
A bath containing 0.4 to 0.8 M of succinic acid as an 8M dicarboxylic acid, or (2) a bath containing 0.4 to 0.8 M of nickel sulfate as a nickel salt.
20M As a reducing agent, sodium phosphinate 0.24-0.
36M oxycarboxylic acid, D, L malic acid 2-0.4
M oxycarboxylic acid, lactic acid 0.3-0.6M dicarboxylic acid, malonic acid 0.2-0.4M Use any of the baths containing the liquid temperature, usually 60 minutes to 5 minutes at a liquid temperature of 80 to 95°C. Let soak for an hour. The thickness of the nickel-phosphorus alloy film is required to be at least 30 μm or more.

The base material on which the nickel-phosphorus alloy film has been formed is washed with water, dried, and then etched to form a black body.

The concentration of the nitric acid aqueous solution used in the etching process is nitric acid:
It has a concentration ranging from water-1:2 to concentrated nitric acid, and is treated at a liquid temperature of 30 to 80°C and an immersion time of 10 seconds to 5 minutes, but these concentrations, liquid temperature, time, etc. The optimum etching conditions are selected in relation to the condition of the nickel-phosphorus alloy film.

After the etching treatment, the blackbody film on the base material obtained by washing with water and drying is extremely stable and has excellent mechanical and moisture resistance, and its total reflectance is 0 in the wavelength range of 320 to 22,000I. It is .04 to 0.1%.

According to observation using a scanning electron microscope, on the surface of the blackbody film obtained by the method of the present invention, a large number of adjacent conical holes with an opening diameter of 1 to 6 μm were mainly formed. In addition, the wall surface of the hole has a large number of irregularities that are finer than the hole. It is thought that these fine irregularities further reduce the total reflectance.

[Function] By etching the nickel-phosphorus alloy film using an electroless nickel-phosphorus alloy plating solution for black body film, micro holes are arranged randomly on the surface of the base material, and many microscopic irregularities are formed on the wall surface of the holes. By forming this, a black body with low total reflectance can be obtained.

As evidenced by observation using an electron microscope, the black body formed by the method of the present invention has (1) a relatively uniform size distribution of fine cone groups compared to those of the prior art; It is.

(2) It is observed that the holes are small in diameter, mainly 1 to 6 μm, and are deep conical holes.

(3) A particularly important point is that the walls of the microscopic holes have countless microscopic irregularities, creating a surface with a new structure that has not been observed before.

Because of this structure, the total reflectance is much lower than before, and is 0.0 in the wide wavelength range of 320 to 2200 nm.
A black body with a total light reflectance of 4-0.1% is obtained.

[Examples] Example 1 In this example, metal is used as the base material, and copper is used as a representative example.

1.1.1- A copper plate base material with a diameter of 8 square cranes and a thickness of 0.3 mm.
Degreased with trichloroethane and alkaline degreasing solution,
After washing with water, pickling with 1:1 hydrochloric acid, and then performing nickel strike plating (electroplating), electroless nickel-phosphorus alloy plating solution for black body film (liquid composition: nickel sulfate 0.1M1) with a bath temperature of 90°C. Sodium phosphinate 0.
25M, D, L-malic acid 0.2M, lactic acid 0.4M, malonic acid 0.25M) or (nickel sulfate 0.1M, sodium phosphinate 0.25M, D,L-malic acid 0
．． 4M, succinic acid 0.45M) for 3 hours to deposit a nickel-phosphorus alloy plating film of 70 to 80 µm on the surface of the substrate. The copper base material on which the nickel-phosphorus alloy plating film was formed in this way was washed with water. Next, in order to make this alloy film a black body, it was etched for 1 minute in a 1=1 nitric acid aqueous solution at a bath temperature of 50°C, washed with water, and dried.

The blackbody film formed on the surface of the copper base material was extremely stable and had excellent resistance to mechanical vibration, friction, and moisture.

FIG. 1 shows the results of measuring the total reflectance of the obtained black body film in the wavelength range of 320 to 2200 nl using an integrating sphere spectrophotometer. The solid line is the measured value, and the total reflectance is as low as 0.05 to 0.08% in the wavelength range of 320 to 2200 ns, and the variation depending on the wavelength is extremely small. After exposing this film to an environment with a relative humidity of 85% RH at 85°C for 200 and 500 hours, the total reflectance determined by DI is shown, and the total reflectance in the entire wavelength range is around 0.1%. , almost no wavelength dependence is observed, and the black body film made by the present invention has a wavelength of 320 to 220
It has been shown that it is an excellent black body over the entire wavelength range of 0 ns.

In FIG. 2, A is the total reflectance measurement value of the black body film of the present invention obtained in this example. B is U.S. Patent No. 4.23
The total reflectance of the black film disclosed in No. 3.107 and No. 4.361,830 is as high as 0.5 to 1.0% compared to the film A. Moreover, wavelength dependence is observed. C is the measured value for the all-black film.

As described above, the present invention is significantly superior to the prior art in terms of total reflectance and its wavelength dependence.

FIG. 3 is a photograph of the surface of the base material having the blackbody film produced in Example 1, observed with a scanning electron microscope. a,
b, c, and d are the results when the magnification is increased sequentially. The magnification factor can be estimated from the scale shown nearby.

As shown in a, fine conical holes are randomly distributed over the surface, and the diameter of the holes is relatively uniform.

An example of the hole diameter distribution is shown in FIG.

It can be seen from this figure that the hole diameter of the hole opening is mainly 1 to 6 μm. In FIG. 3, as the magnification is gradually increased from b to c to d, it becomes clear that even smaller microscopic irregularities are formed on the walls of the microscopic holes. That is, the black body film formed by the method of the present invention has a surface structural feature in that smaller fine irregularities are formed on the surface of the wall surface of the microhole. The same applies to FIG.

Figure 5 shows prior art U.S. Patent No. 4.233°10.
This is a photograph of the surface of a black film prepared based on the method disclosed in No. 7 and No. 4.361.830, observed with a scanning electron microscope. In order to contrast with Fig. 3.4, a, b, c, and d have been similarly increased in magnification sequentially. Figure 5a shows conical holes randomly distributed on the surface.
It can be seen that the diameters of the conical holes vary in size. The hole diameter distribution is shown in FIG. The most important difference in surface photograph observation between Figures 3, 4, and 5 is d
It is recognized in In FIGS. 3 and 4, smaller fine irregularities are formed on the walls of the microholes.

Table 1 displays a comparison between the prior art and the method of the present invention.

In addition, for base materials such as iron, nickel, and cobalt, t,
Degreasing is performed using i, t-trichloroethane, followed by alkali degreasing, washing with water, pickling with 1:1 hydrochloric acid, washing with water, and electroless nickel for blackbody film at a bath temperature of 90°C.
It was immersed in a phosphorus alloy plating solution for 3 hours to deposit a nickel-phosphorus alloy plating film of about 70 to 80 μm on the surface of the base material.

This film was subjected to the etching treatment described in the previous section to turn the film into a black body. The surface structure, light absorption characteristics, etc. of the blackbody film thus obtained were the same as those of the blackbody film obtained using a copper base material.

Furthermore, regarding aluminum as a base metal, 1
．． 1.1- Degreasing was performed with trichloroethane, and etching was performed for 3 to 5 minutes with a sodium hydroxide solution at room temperature. After washing with water, soak in a mixture of nitric acid and hydrofluoric acid at room temperature for 15~
Dip for 20 seconds to remove smut generated on the aluminum surface, wash with water, replace with zinc, wash with water and perform copper strike and nickel strike plating (electroplating), then electroless nickel for black body coating in a warm bath of 90°C. Approximately 70 to 80 μl of phosphorus alloy plating film is deposited. This film was subjected to the etching treatment described in the previous section to turn the film into a black body. The surface texture, light absorption characteristics, etc. of the blackbody film thus obtained were the same as those of the blackbody film obtained using a copper base material.

Furthermore, base materials such as brass, bronze, cupronickel, phosphor bronze, stainless steel, and 18-karat gold are subjected to the same pretreatment as the copper base material, and the surface of the base material is coated with nickel for black body coating.
A phosphorus alloy film was deposited to a thickness of about 70 to 80 μm, and the etching treatment for forming a black body described in the previous section was performed. The surface structure, light absorption characteristics, etc. of the obtained blackbody film were the same as those of the blackbody film obtained on a copper base material.

Example 2 In this example, ceramics and glass were used as the base material. Since ceramics and glass are nonconductors, a vacuum evaporation method was used to first deposit nichrome, then gold, and nickel strike plating to metalize the surface. Alternatively, as a chemical reduction method, ceramic and glass surfaces were activated by immersion in a colloidal palladium suspension, immersion in a palladium chloride solution, or immersion in a tin chloride solution and then a palladium chloride solution.

These surface-metallized and activated ceramics and glasses were heated in a hot bath at 90°C using an electroless nickel-phosphorus alloy plating solution for black body coatings (liquid composition: nickel sulfate 0, IM, sodium phosphinate 0.25M).

D, L-malic acid 0.5M, lactic acid 0.4M, malonic acid 0
．． 25M) or (liquid composition: nickel sulfate 0.1M, sodium phosphinate 0.25M.

D, L-malic acid 0.4M, succinic acid 0.45M) to 3
A nickel-phosphorus alloy plating film of about 70 to 80 μm was deposited on the surface of these substrates by dipping for a time, and then Example 1
The etching process for black body conversion described in . As a result, various properties such as the surface structure and total reflectance of the black body film obtained were the same as those of the black body film obtained in Example 1, and no particular differences were found.

Example 3 In this example, plastic was used as the base material.

Since plastic is a nonconductor, it was metallized using cathode sputtering. Alternatively, as a chemical reduction method, the plastic surface may be activated by immersion in a colloidal palladium suspension, immersion in a palladium chloride solution, or immersion in a tin chloride solution and then a palladium chloride solution. These surface-metallized and activated plastics were coated with an electroless nickel-phosphorus alloy plating solution for blackbody coatings at a bath temperature of 90°C (liquid composition: nickel sulfate 0.1M, sodium phosphinate 0.25M, D, L-apple). acid 0.5M
, lactic acid 14M, 70:/acid 0.3M) or nickel sulfate 0.1M, sodium phosphinate 0.25M, D
, L-') > Golic acid 0.4M.

A nickel-phosphorus alloy plating film was deposited on the surface of the plastic by about 70 to 80 μm by immersion in 0.45 M chloride/l acid for 3 hours, and was then subjected to the etching treatment for blackening as described in Example 1. The various properties of the black body film, such as the surface structure and total reflectance of light, were the same as those of the black body film obtained in Example 1, and no particular differences could be found.

[Effects of the Invention] The present invention applies regardless of the type of base material. (1) Nickel salt, sodium phosphinate, D, L-
A plating solution having a composition of malic acid or its salt, and succinic acid or its salt, or (2) nickel salt, sodium phosphinate, D.

Precipitating a nickel alloy plating film using a plating solution with a composition of L-malic acid or its salt, lactic acid or its salt, and malonic acid or its salt, and converting it into a horse body by etching with an aqueous nitric acid solution. As a result, an ideal blackbody film was formed.

This black body film mainly consists of a large number of adjacent conical holes with an opening diameter of 1 to 6 μm, and many fine irregularities formed on the walls of the holes, so that light is totally reflected. The rate is low over a wide wavelength range. In other words, it has low wavelength dependence in the wavelength range of 320 to 2200 nm, is resistant to mechanical vibration and friction, is stable against moisture resistance, and has a total reflectance of 0.
．． A film having an extremely low reflectance of 0.04 to 0.1% is formed.

In this way, an ideal blackbody film can be formed on most industrial materials such as metals, ceramics, and plastics, making it useful as a light absorber. It is extremely useful as a terminal element for optical transmission systems, and can also be used as an antireflection material inside optical equipment, an antireflection material inside optical connectors, etc.

[Brief explanation of the drawing]

FIG. 1 is a graph showing changes in total reflectance of the black body film of the present invention depending on humidity. Figure 2 shows the prior art, U.S. Patent No. 4.361゜63.
1 is a graph comparing the total reflectance of the black film disclosed in the specification of No. 0 and the total black film with the black body film of the present invention. Figures 3(a) to 3(d) and 4(a) to 4(d) are enlarged views of the surface structure of the blackbody film of the present invention etched with an etching solution, respectively. 5(a) to 5(d) are scanning electron micrographs shown in FIGS. 5(a) to 5(d), which are disclosed in prior art US Pat. These are scanning electron micrographs showing enlarged sequentially the surface structure of a film corresponding to a black film. FIG. 6 is a diagram showing the hole diameter distribution of holes on the surface of the blackbody coating according to the present invention shown in FIGS. 3, 4, and 5. FIG. Applicant's agent Patent attorney Takehiko Suzue Zentai M (0mu)! ';r Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) Comprising a base material and a black body coating of a nickel-phosphorus alloy formed on the surface of the base material, the surface of this black body coating is mainly conical with an opening hole diameter of 1 to 6 μm. A large number of holes are formed adjacent to each other, and a large number of irregularities finer than the holes are formed on the wall surface of the hole, so that the total reflectance of the black body is 0.04 to 0.1% in the wavelength range of 320 nm to 2200 nm. A substrate with a certain blackbody film. (2) Nickel salt, sodium phosphinate, D,L-
A step of plating a nickel-phosphorus alloy film on a substrate using a nickel-phosphorus alloy plating solution for black body film consisting of malic acid or its salt, succinic acid or its salt, and the surface of the nickel-phosphorus alloy film. A method for producing a base material with a blackbody film, which comprises etching with an aqueous nitric acid solution. (3) Nickel salt, sodium phosphinate, D,L-
a step of plating a nickel-phosphorus alloy film on a substrate using a nickel-phosphorus alloy plating solution for black body film consisting of malic acid or its salt, lactic acid or its salt, malonic acid or its salt; - A method for producing a substrate with a blackbody film, which comprises etching the surface of the phosphorus alloy film with an aqueous nitric acid solution.