JPH0527708B2 - - Google Patents

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 base material using a nickel-phosphorus alloy plating liquid for blackbody films invented by the inventors, and then to coat this alloy film with a specific chemical substance. It is formed by etching. The optical black coating of the present invention has a low total reflectance, and its wavelength dependence is also extremely small.
From this, an ideal black body film can be realized, and can be effectively used in the light receiving part of an optical calorimeter, the termination element system of an optical transmission system, an optical waveguide, the inner surface of an optical connector, etc. [Prior art] 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 anodizing. A black film containing black dye was formed on the quality film. but,
These black films have a total reflectance of about 3 to 10% and are highly wavelength dependent.
It was unsatisfactory for use as a light receiving part of an optical calorimeter. On the other hand, a film with a lower total reflectance than the above-mentioned film is gold black produced by a vapor deposition oxidation method. The gold-black film has a total reflectance of about 0.5%, which is much lower than the gold-black paint mentioned above, and is used as the light receiving part of optical calorimeters. Also, U.S. Patent No. 4,233,107 (corresponding patent: Japanese Patent Application Laid-Open No. 1983-1998) related to the invention of CE Johnson, Sr.
No. 114655) discloses a black film obtained by etching a nickel-phosphorus plating film with an aqueous nitric acid solution and a method for producing the same. A similar invention is also disclosed in US Pat. No. 4,361,630 by the same inventor. This technology
Improved by PL Gleason, U.S. Patent No.
It is disclosed in the specification of No. 4511614. [Problem to be solved by the invention] Gold black easily flakes off due to mechanical vibration or friction, absorbs moisture under high humidity conditions and increases total reflectance, and even when dry, the original reflectance is restored. There is a problem that the rate does not recover, and there are many practical difficulties. In addition, the black film disclosed in U.S. Patent Nos. 4,233,107 and 4,361,630 has a total reflectance of
It is 0.5 to 1.0% and has high film strength, making it highly practical. However, the total reflectance has wavelength dependence,
Since the fluctuation range is 0.34% to 0.41%, 320
There are still problems in using it as a photoreceptor for measuring optical power with high precision in a wide wavelength band of ~2200 nm. Furthermore, the technology disclosed in US Pat. No. 4,511,614 is composed of a base material with a two-layer structure in which two layers with different concentrations of phosphorus in the nickel-phosphorus film are stacked. Therefore, the number of manufacturing steps is increased, and the total reflectance is higher than the above two inventions, and the fluctuation range of the total reflectance is also large. The purpose of the present invention is to firstly produce metals, ceramics,
Light-absorbing substrates with a black body film formed on the surface of the substrate, such as glass or plastics, that has low total reflectance, low wavelength dependence, and excellent mechanical strength and moisture resistance, and the black material used therefor. An object of the present invention is to provide a method for forming a body film. The second object is to provide a base material having a practical black body film that has better mechanical strength than gold 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 Gleason. [Means for Solving the Problems] In order to achieve these objects, a base material having a black body film according to the present invention includes a base material and a nickel-phosphorus alloy black body formed on the surface of the base material. On the surface of this black body film, a large number of conical holes with an opening diameter of 1 to 6 μm are formed adjacent to each other. Many fine streak-like irregularities are formed, and the wavelength range is 320 nm.
The total reflectance of a blackbody is 0.04-0.1% at ~2200nm
and the fluctuation width of the total reflectance depending on the wavelength in the wavelength range of 320 nm to 2200 nm is 0.1% or less. The method for producing a base material having a black body film includes: 1. Nickel salt, sodium phosphinate,
Contains D,L-malic acid or its salt and succinic acid or its salt, and the total amount of D,L-malic acid or its salt and succinic acid or its salt is
Nickel for black body film with a content of 0.8 to 1.6 mol/
The method includes a step of plating a nickel-phosphorus alloy film on a substrate using a phosphorus alloy plating solution, and a step of etching the surface of the nickel-phosphorus alloy film with an aqueous nitric acid solution. In addition, 2 nickel salt, sodium phosphinate,
Using a nickel-phosphorus alloy plating solution for black body film containing D,L-malic acid or its salt, lactic acid or its salt, and malonic acid or its salt,
The method includes a step of plating a nickel-phosphorus alloy film on a base material, and a step of etching the surface of the nickel-phosphorus alloy film with an aqueous nitric acid solution. This plating solution was determined through experiments by the inventor. In this invention, metal, 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 blackbody 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, and then subjected to nickel strike plating, using an electroless nickel-phosphorus alloy plating solution for blackbody coatings. Nickel with a phosphorus concentration of 7 to 10% is applied to the surface of the base material by immersing it in
A phosphorus alloy film is formed. 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/phosphorus plating solution for blackbody coating is applied. A nickel-phosphorus alloy film is formed by For electroless nickel-phosphorus alloy plating for blackbody coatings, use the following as a plating solution: (1) Nickel sulfate as a nickel salt.
0.11~0.20M Sodium phosphinate as reducing agent
0.24-0.36M As oxycarboxylic acid, D, L malic acid
A bath containing 0.4-0.8M succinic acid as a 0.4-0.8M dicarboxylic acid, or (2) nickel sulfate as a nickel salt.
0.11~0.20M Sodium phosphinate as reducing agent
0.24-0.36M As oxycarboxylic acid, D, L malic acid
Use one of the baths containing 0.2-0.4M lactic acid as oxycarboxylic acid, 0.3-0.6M malonic acid as dicarboxylic acid, and immerse at a liquid temperature of usually 80-95°C for 60 minutes to 5 hours. . The thickness of the nickel-phosphorus alloy film must be at least 30 μm or more. The base material on which the nickel-phosphorus alloy film is formed is
After washing with water and drying, it is etched to form a black body. The concentration of the nitric acid aqueous solution used in the etching process ranges from nitric acid:water = 1:2 to concentrated nitric acid, and the solution temperature is 30 to 80°C, and the immersion time is 10 seconds to 5 minutes. However, the etching conditions such as concentration, liquid temperature, time, etc. are selected optimally in relation to the state of the nickel-phosphorus alloy film. After etching, 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 320~320.
In the wavelength range of 2200 nm, it is 0.04 to 0.1%. According to observation using a scanning electron microscope, the surfaces of the black bodies and membranes obtained by the method of the present invention mainly have a large number of adjacent conical holes with opening diameters of 1 to 6 μm. , and the wall surface of the hole has many finer irregularities than the hole. It is thought that these fine irregularities further reduce the total reflectance. [Function] In the black body film according to the present invention, when light is incident on the film surface, it undergoes multiple reflections inside the conical hole, is absorbed by the fine streak-like unevenness, and most of the light is absorbed by the black body film surface. Absorbed. As a result, 320~
Total reflectance in the wavelength range of 2200nm is 0.04~0.1%,
The total reflectance varies by wavelength by less than 0.1%. In the method for producing a blackbody film according to the present invention, first, a base material is immersed in the above-mentioned nickel-phosphorus alloy plating solution according to the present invention to deposit a nickel-phosphorus alloy plating film on the surface of the base material. Next, the surface of the alloy plating film is etched with a nitric acid aqueous solution to make the surface of the alloy plating film a black body. A large number of holes are formed adjacent to each other, and a large number of streak-like irregularities that are finer than the holes are formed on the wall surfaces of the holes. [Examples] Example 1 In this example, metal is used as the base material, and copper is used as a representative example. 1, 1, 1 copper plate base material with a diameter of 8 mm and a thickness of 0.3 mm
- After degreasing with trichloroethane and alkaline degreasing solution, washing with water, pickling with 1:1 hydrochloric acid, and then performing nickel strike plating (electroplating), electroless nickel for black body film with a bath temperature of 90°C.・
Phosphorus alloy plating solution (liquid composition: nickel sulfate 0.1M,
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 coat the surface of the substrate with nickel.
A phosphorus alloy plating film of 70 to 80 μm was deposited. The copper base material on which the nickel-phosphorus alloy plating film had been formed was washed with water. Then, 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 nm using an integrating sphere spectrophotometer. The solid line is the measured value, 320~
The total reflectance is as low as 0.05 to 0.08% in the 2200 nm wavelength range, and variation with wavelength is extremely small. For example, as is clear from Figure 1, the total reflectance is 0.07% at a wavelength of 320 nm, the total reflectance is 0.07% at a wavelength of 633 nm, and
The total reflectance is 0.08% at 1200 nm and 0.09% at a wavelength of 2200 nm, and the fluctuation range of the total reflectance depending on the wavelength is 0.1% or less. The total reflectance measured after exposing this film to an environment of 85°C and relative humidity 85% RH for 200 and 500 hours is shown, and the total reflectance in the entire wavelength range is around 0.1%, which is wavelength dependent. The blackbody film produced by this invention has almost no
It has been shown that it is an excellent blackbody over the entire wavelength range from 320 to 2200 nm. 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 the total reflectance of the black film disclosed in U.S. Pat. can be seen. C is the measured value for the gold-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 black body film produced in Example 1, observed with a scanning electron microscope. a, d, 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. From this figure, the hole diameter of the hole opening is mainly 1 to 6μ.
It turns out that m. In Figure 3, b,
As the magnification is gradually increased from 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. 4,233,107.
This is a photograph taken with a scanning electron microscope of the surface of a black film prepared based on the method disclosed in No. 1 and No. 4,361,630. In order to contrast with FIGS. 3 and 4, the magnifications of a, b, c, and d were similarly increased sequentially. In Fig. 5a, it can be seen that conical holes are randomly distributed on the surface, and the diameters of the conical holes are distributed in various sizes. The hole diameter distribution is shown in FIG. The most important difference in surface photograph observation between FIGS. 3, 4, and 5 is observed in d. 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, base materials such as iron, nickel, and cobalt are also degreased using 1,1,1-trichloroethane, then alkaline degreased, washed with water, pickled with 1:1 hydrochloric acid, and washed with water. 3 for electroless nickel-phosphorus alloy plating solution for black body film with bath temperature of 90℃
By dipping for a time, a nickel-phosphorus alloy plating film of about 70 to 80 μm was deposited on the surface of the substrate. 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 black body film thus obtained were the same as those of the black body film obtained using a copper base material. Further, aluminum as the base metal was also degreased with 1,1,1-trichloroethane and etched with a sodium hydroxide solution at room temperature for 3 to 5 hours. After washing with water, immerse it in a mixture of nitric acid and hydrofluoric acid at room temperature for 15 to 20 seconds to remove the smut that has formed on the aluminum surface. ), an electroless nickel-phosphorus alloy plating film for a blackbody film is deposited in a thickness of about 70 to 80 μm in a hot bath of 90°C. 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 black body film thus obtained were the same as those of the black body 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. Approximately 70~80μ phosphorus alloy film
m was precipitated, and the etching treatment for blackbody formation 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 metallize the surface by nickel strike plating. or as a chemical reduction method, by immersion in a colloidal palladium suspension,
Ceramic and glass surfaces were activated by immersion in a palladium chloride solution or by immersion in a tin chloride solution followed by a palladium chloride solution.
Electroless nickel-phosphorus alloy plating solution for black body film (liquid composition: nickel sulfate)
0.1M, 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,
0.45M succinic acid) for 3 hours to form a nickel-phosphorus alloy plating film on the surface of these substrates for about 70~
A thickness of 80 μm was deposited, and then the etching treatment for blackbody formation described in Example 1 was performed. the result,
The surface structure, total light reflectance, and other properties of the obtained black body film 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 cathodic sputtering. or as a chemical reduction method, by immersion in a colloidal palladium suspension,
The plastic surface may be activated by immersion in a palladium chloride solution or by immersion in a tin chloride solution followed by a palladium chloride solution. These surface-metalized and activated plastics are heated to a bath temperature.
Electroless nickel-phosphorus alloy plating solution for black body film at 90°C (liquid composition: nickel sulfate 0.1M, sodium phosphinate 0.25M, D,L-malic acid 0.5M,
Lactic acid 0.4M, malonic acid 0.3M) or (nickel sulfate 0.1M, sodium phosphinate 0.25M, D,
The plastic was immersed in L-malic acid (0.4 M, succinic acid 0.45 M) for 3 hours to deposit a nickel-phosphorus alloy plating film of approximately 70 to 80 μm on the plastic surface, and then subjected to the etching treatment for blackening as described in Example 1. The surface structure, total light reflectance, and other properties of the black body film thus obtained were the same as those of the black body film obtained in Example 1, and no particular differences were found. [Effects of the Invention] The present invention applies regardless of the type of base material, (1) nickel salt, sodium phosphinate, D,
A plating solution having a composition of L-malic acid or its salt, and succinic acid or its salt, or (2) nickel salt, sodium phosphinate, D,
A nickel alloy plating film is precipitated and formed 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 this is turned into a black body by etching treatment with an aqueous nitric acid solution. As a result, an ideal blackbody film was formed. This blackbody coating mainly has an opening hole diameter of 1 to 6 μm.
A large number of conical holes of m diameter are formed adjacent to each other, and a large number of fine streak-like irregularities are formed on the wall surface of the hole, so these conical holes and fine streak-like irregularities cause multiple The reflected light is efficiently absorbed. As a result, the total reflectance is low over a wide wavelength range,
In addition, the wavelength dependence of total reflectance is small. That is,
The blackbody coating according to the present invention has a total reflectance of 0.04 to 0.1% in the wavelength range of 320 to 220 nm, and a fluctuation width of the total reflectance depending on the wavelength of 0.1% or less, and has a much higher total reflectance than conventional blackbody coatings. It has the remarkable effects of low reflectance, small fluctuation range of total reflectance that shows wavelength dependence, and excellent mechanical strength and moisture resistance. Furthermore, by selecting the combination and amount of organic acids, the method for producing a blackbody film according to the present invention can improve the immersion time, corrosion temperature, alloy composition (phosphorus content, etc.) without increasing the number of steps. ) has the remarkable effect that it is possible to obtain a black body film with good optical properties, which cannot be obtained by the conventional method of manufacturing a black body film, in which the degree of blackening is controlled by changing the black body film. In this way, ideal blackbody films can be formed on most industrial materials such as metals, ceramics, and plastics, making them useful as light absorbers.
The obtained film is extremely useful as a light absorber for precise absolute value measurement of optical power or as a termination element for optical transmission systems, and can also be used as anti-reflection material inside optical equipment, anti-reflection material inside optical connectors, etc. can do. 【table】

[Brief explanation of drawings]

FIG. 1 is a graph showing changes in total reflectance of the black body film of the present invention depending on humidity. FIG. 2 is a graph comparing the total reflectance of the black film and gold black disclosed in the prior art US Pat. No. 4,361,630 with the black body film of the present invention. Figures 3a to 3d and Figures 4a to 4d are scanning electron micrographs showing enlarged sequentially the surface structure of the black body film of the present invention etched with an etching solution, respectively. FIGS. 5a to 5d are scanning electron microscopes showing sequential enlargements of the surface structure of a film corresponding to the black film disclosed in prior art US Pat. Nos. 4,233,107 and 4,361,630. It's a photo. FIG. 6 is a diagram showing the hole diameter distribution of holes on the surface of the black body coating according to the present invention shown in FIGS. 3, 4, and 5. FIG.

Claims (1)

[Claims] 1. A base material and a nickel film formed on the surface of the base material.
A black body film made of phosphorus alloy is formed on the surface of the black body film, and a large number of conical holes, mainly having an opening diameter of 1 to 6 μm, are formed adjacent to each other. Many streak-like irregularities are formed on the wall surface, which are finer than these holes, and the total reflectance of the black body is 0.04 to 0.1% in the wavelength range of 320 nm to 2200 nm, and the wavelength range is 320 nm.
A base material having a black body film whose total reflectance varies by wavelength in the wavelength range of m to 2200 nm. 2 Nickel salt, sodium phosphinate,
Contains D,L-malic acid or its salt and succinic acid or its salt, and the total amount of D,L-malic acid or its salt and succinic acid or its salt is 0.8 to
A step of plating a nickel-phosphorus alloy film on a substrate using a nickel-phosphorus alloy plating solution for black body film having a concentration of 1.6mol/2, and etching the surface of the nickel-phosphorus alloy film with an aqueous nitric acid solution. A method for producing a base material with a black body film, comprising the steps of: 3 Nickel salt, sodium phosphinate,
A nickel-phosphorus alloy film is formed on a substrate using a nickel-phosphorus alloy plating solution for black body film containing D,L-malic acid or its salt, lactic acid or its salt, and malonic acid or its salt. The process of plating,
A method for producing a substrate with a black body film, comprising the step of etching the surface of the nickel-phosphorus alloy film with an aqueous nitric acid solution.