JP2937484B2 - Methods and products for plasma enhanced electrochemical surface ceramicization - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a surface chemical treatment, particularly to a surface chemical treatment of a metal material.

BACKGROUND ART With the development of modern industry and science and technology, ceramic materials have become the third generation industrial materials after steel and aluminum materials due to their unique performance and abundant resources.
Ceramic materials have high brittleness and poor workability, so their widespread application has been restricted. Implementing a ceramic coating on the surface of metals and alloys allows the use of cheaper metallic materials in place of expensive noble metals and alloys, while guaranteeing the performance of use, while at the same time allowing the metallic material itself to have other surfaces. Gives special performance not obtainable by enhanced technology, and widens its application range. On the other hand, the use of surface ceramics for workable materials has improved the formability and workability of ceramic materials, has enabled the manufacture of ceramic parts with complex shapes, and has opened a new avenue for widespread application of ceramics.

At present, there are two methods for converting a metal or alloy to a surface ceramic, which is plasma spraying and laser firing after applying solid powder. That is, another powder material or a part of the powder of the metal member is fired on the surface of the metal by high-density energy to obtain a ceramic film.

The solid powder generally used for the plasma spraying technique and the laser fusion coating technique is a powder of a compound of a metal, carbon, oxygen and boron. These form a ceramic layer on the surface of the main body after firing by high energy. The hard particles mainly consist of metal (transition group) and carbon,
It consists of compounds with nitrogen and boron (about 40-90%), and the other solid phase components make up about 10-60%. The surface ceramic film produced by plasma spraying and laser fusion coating technology is an inlaid deposit with an irregular appearance,
Has relatively high porosity and few macroscopic defects. Each component in the coating is unevenly distributed, the bond between the coating and the body is mechanical, and there is a clear interface. Both of these methods have the following disadvantages: 1. Poor uniformity of the ceramic film after processing, problems in dimensional accuracy and surface roughness, and great difficulty in reshaping and repairing.

2. The mechanical bond between the metal and alloy material and the ceramic film is a large amount of pores and internal stress in the ceramic layer, and the bond strength, impact resistance and corrosion resistance are not ideal .

3. There is a high demand for the dimensions of the parts to be machined, and the difficulty of machining parts with through holes and closed holes and parts with unique shapes is great.

4. Plasma spraying and laser melt coating have an excessive burn phenomenon on the member, which affects the performance.

In addition, a common chemical treatment of metals or alloys (eg, aluminum alloys) is anodization. For example, in the case of aluminum, this method performs anodization in an acidic electrolyte solution (for example, an aqueous sulfuric acid solution) using the aluminum member as an anode. In the case of the sulfuric acid method, the aluminum anode reacts with the interfacial electrolyte as follows: Al = Al ³⁺ + 3e (1) 3SO ₄ ^2- + 3H ₂ O = 3H ₂ SO ₄ +3 [O] + 6e (2) 3 [ _{O] + 2Al = Al 2 O} 3 (3) Al 2 O 3 + H 2 O = Al 2 O 3 · H 2 O (4) Al 2 O 3 · H 2 O + 3H 2 SO 4 = Al 2 (SO 4) 3 + 4H ₂ O (5) Al ₂ O ₃ + 3H ₂ SO ₄ = Al ₂ (SO ₄ ) ₃ + 3H ₂ O (6) As can be seen from the reaction formulas (1), (2), (3) and (4), the anode The nascent (first ecological) oxygen deposited on
Bonds with aluminum atoms on the anode (member) surface to produce aluminum oxide. The structure of the inner oxide film formed from aluminum oxide is dense and relatively high in hardness.
It has a thickness of 0.01-0.05 μm. The layer of aluminum oxide is hardly permeated by the electrolyte and is called a barrier layer. The outer oxide film in contact with the electrolyte is composed of aluminum oxide and alumina monohydrate. There are many holes in this oxide film layer, and the electrolyte easily permeates through these holes. When a voltage is applied, the pores in the layer constantly increase, increasing the depth and thickness of the layer, which is a film-forming effect. As can be seen from the reaction formulas (5) and (6), the film of aluminum oxide and alumina monohydrate, which is in contact with the electrolytic solution and through which the electrolytic solution permeates, is gradually dissolved by the sulfuric acid electrolytic solution to form a film. And this is a membrane dissolving effect. Therefore, a film-forming action and a film-dissolving action simultaneously exist during the anodization of aluminum and its alloy members. It is necessary to appropriately control the disposal components of the anodizing solution and the process conditions so that the film formation rate is higher than the film dissolution rate. In this way, a microporous oxide film having a certain thickness is formed on the surface of the anode (member). The surface profile of such membranes formed by conventional anodization techniques is a capillary porous structure, and the distribution of components in the membrane is relatively uniform, and the bonding between the membrane and the member Is dense. The chemical composition of the film is generally Al ₂ O ₃ and Al ₂ O ₃
H ₂ O accounts for 95.0 to 99.0% of the entire film, and other impurities
1.0 to 5.0%. These conventional anodic oxidation techniques have the following deficiencies: 1. The porosity of the film is large, the abrasion resistance is poor, and the hardness is low.

2. The color of the film is monotonous, the color gloss is poor, the performance and the base of ceramics are lacking, and the decorativeness is poor.

EP0462073, EP0280886, CN87103694 and US3,834,99
9 performs an arc discharge on the surface of the metal material by a chemical reaction in the electrolytic solution and a plasma chemical reaction, respectively.
A method for forming a ceramic film of a metal oxide by anodizing is disclosed. These methods have the following disadvantages: 1. Poor uniformity of the processed ceramic film, problems in surface dimensional accuracy and roughness, and difficulty in reshaping and repairing.

2. The color and pattern of the product are monotonous and the decoration effect is inferior.

3. Low electrolyte stability, short service life and high cost.

An object of the present invention is to overcome the above deficiencies existing in the prior art, and to provide a method for electrochemically ceramicizing a metal surface in a novel electrolyte system containing sodium hexametaphosphate.

Another object of the present invention is to provide a metal product having a ceramic film.

DISCLOSURE OF THE INVENTION The process of the present invention mainly comprises 10 to 50 g / l sodium hexametaphosphate, 5 to 20 g / l boric acid and / or borax, and further comprises sodium orthophosphate, sodium sulfate, sodium silicate , Ammonium metavanadate,
Sodium metavanadate, sodium chromate, sodium tungstate, cobalt sulfate, nickel sulfate,
At least one selected from the group consisting of iron sulfate, manganese sulfate, and chromium sulfate oxygen-containing salt, and optionally calcium, zinc, cobalt, nickel acetate, fluorosilicic acid, potassium fluoride, ethylenediamine In an electrolyte solution containing an additive selected from the group consisting of tetraacetic acid, at 10-50 ° C., a voltage of 100-400 V and 0.5
The energy generated by the current density of the through 20a / dm ^2, on the surface of the metal member of the anode is a plasma arc discharge performed electrochemical anodic oxidation, the electrolyte to take part in the reaction was baked on the surface of the member, the coating of ceramic structure Forming step.

In the method of the present invention, the process of forming the ceramic film is as follows: In an electrochemical oxidation electrolysis cell, a metal member is used as an anode, and a DC electric field is applied between the anode and the cathode to form a surface of the member. Anodization reaction occurs: Al = Al ³⁺ + 3e OH = 1 / 2H ₂ O + 1/2 [O] + e 2Al + 3 [O] = Al ₂ O ₃ Accordingly, a dense oxide thin film having a thickness of 0.01 to 0.2 μm To form This film is relatively thin, has electrical insulation, and is called a barrier layer. With increasing voltage between the anode and cathode, the electric field strength becomes very high (about 10 ⁷ V / c
m) Due to this, a phenomenon of dielectric breakdown may occur on the surface of the anode, and plasma arc discharge occurs on the surface of the anode member.
The arc discharge is generated in a film defect, a place with a gap, and a thin place. The energy density at these points is extremely high (approximately 10 ⁴ to 10 ⁷ W / cm ² ), causing a series of chemical reactions at the interface between the anode surface and the electrolyte, causing some substances in the electrolyte to ionize. Activate. In addition to causing an electrochemical anodic oxidation reaction by the action of enhancing the plasma arc discharge, some electrolytes also participate in the electrochemical reaction and fire on the surface of the member to form a ceramic structure film.

The method of the present invention further includes a step of cleaning the metal member before the anodization, and a step of rinsing and finishing the metal member after the anodization. Therefore, the method of the present invention includes the following steps: 1. Washing Various oils and fats which are present on the surface of a member such as aluminum, titanium, niobium and zirconium by the manufacturing and processing steps are subjected to oxidation processing. Must be thoroughly cleaned before. Preferably, an alkaline cleaning solution having the following composition is used: 50-60 g / l sodium phosphate,
10-15 g / l sodium silicate, 10-20 g / l sodium carbonate, 0.1-10 ML / l surfactant. At the time of cleaning, the cleaning liquid is vigorously stirred or the cleaning liquid is sprayed onto the surface of the member in a container to clean the member cleanly. The cleaning temperature is 40
6060 ° C. and the impregnation time is 20-30 minutes. The cleaned components are placed in a rinsing vessel and rinsed with water at a temperature of 15-50 ° C. until no cleaning liquid is present on the surfaces of the components.

2. Oxidation By using different electrolytes and controlling different processing current, voltage, solution temperature and stirring intensity and method, products with different colors, different designs, different colors and patterns, different performance can be obtained. These apply to different fields. The voltage at which arc discharge is generated is generally 100 to 400V.

The following describes each process for manufacturing different products. Here, V indicates a voltage for generating a plasma arc discharge, and i indicates a machining current.

(1) Method for producing white ceramic color ceramic film Composition of electrolyte solution: sodium hexametaphosphate 10-50 g / l sodium phosphate 10-30 g / l borax 5-20 g / l calcium acetate 0.1-5 g / l sodium silicate 0.1 ~ 10g / l Zinc acetate 0.1 ~ 12g / l Sodium sulfate 5 ~ 10g / l Boric acid 5 ~ 20g / l For substances above, use chemical grade reagents (or purified products for special applications). A solution is prepared in distilled water. The order of preparation is as follows: First, the sodium hexametaphosphate is thoroughly dissolved and the other substances are added.
Adjust the pH to 4.0-0.5 with phosphoric acid. 24 prepared solutions
Leave for more than an hour. The temperature of the solution is controlled at 15-45 ° C, and the solution is uniformly stirred by forced jet stirring. Machining current i = 0.5-5A / dm ² , voltage V = 100-400V, oxidation time 7-30
By the process under the conditions of minutes, a ceramic film of white magnetic color can be produced. The thickness is 5-28 μm.

(2) Manufacturing method of blue ceramic film Composition: (NaPO ₃ ) ₆ 10 to 50 g / l H ₃ BO _{3 5 to} 20 g / l EDTA 1 to 6 g / l Na ₂ SO _{4 5 to} 10 g / l Na ₃ PO _{4 · 12H 2 O 5~15g / l} CoSO 4 5~20g / l NiSO 4 1~10g / l Co (Ac) 2 10~20g / l pH = 4.0~6. The preparation method is the same as the above (1). The solution was left for at least 24 hours, and the temperature of the solution was t = 10-
30 ° C. There are two types of products to be processed. The first product is a uniform blue film. The second product is a film that is dotted with blue and has a decorative effect. Process conditions: current i =
0.5~10A / dm ^2, voltage V = 150~300V. When preparing a uniform blue film, the solution is stirred vigorously for 5-20 minutes to make the solution completely homogeneous. When preparing a film that is dotted with blue and has a decorative effect, the method of stirring the solution is changed, the concentration of the solution is changed, a difference in the concentration is caused, the number of discharge centers on the surface of the member is reduced, And increase the current density at the discharge center,
It discharges some substances and produces color spots of different sizes on the surface. Thereby, a film having a beautiful decorative effect can be obtained. The specific process is that the current i = 0.5 to 7 A /
Control to dm ² and agitate the solution forcibly for 5-10 minutes (as in the above process) and then leave for 3-5 minutes. Thereafter, during 1 to 5 minutes, the solution is agitated abruptly, or the member is moved in the container to greatly change the concentration.
Thereby, decorative films having different color points can be obtained. The thickness of the film is 5 to 15 μm, and the color of the film is light blue to deep blue. The conditions of this process can also be used in preparing products of other colors.

(3) milky film _{composition: (NaPO 3) 6 10~50g /} l Na 3 PO 4 · 12H 2 O 5~10g / l H 3 BO 3 5~10g / l Ni (Ac) 2 2~15g / l _{Na 2 SO 4 5~10g / l Na} 2 B 4 O 7 · 7H 2 O 5~10g / l Fe 2 (SO 4) 3 2~10g / l EDTA 1~6 g / l MnSO 4 · H 2 O 2 ~ 10 g / l The preparation method is the same as in the above (1). The process conditions were: pH = 4-6, solution temperature t = 14-45 ° C., current i = 0.
5 to 10 A / dm ² , V = 125 to 350, oxidation time t = 5 to 20 minutes, and film thickness 5 to 25 μm. The stirring method of the above (1) is used. A pale milky to deep milky film is obtained.

(4) deep pink film _{composition: (NaPO 3) 6 10~50g /} l Na 2 B 4 O 7 · 7H 2 O 5~20g / l Na 3 PO 4 · 12H 2 O 10~30g / l Na 2 SiO ₃ 0.5 to 10 g / l Zn (Ac) ₂ 0.1 to 12 g / l MnSO ₄ .H ₂ O 5 to ₂₀ g / l The preparation method is the same as the above (1). Process conditions: current density i = 0.5-10 A / dm ² , V = 150-350 V, temperature = 10-40 ° C. There are two types of products from this process. Like the blue film of the above (2), one is a deep pink film, and the other is a film having a different color point and having a decorative effect. As in the process (2), a film having a uniform color can be obtained by normal stirring, and a decorative film having a relatively large color point can be obtained by a special stirring method. The oxidation time is t = 5-25 minutes and the thickness is 5-25 μm. This results in a deep pink film.

(5) the film composition of the _{brown-black: (NaPO 3) 6 10~50g /} l Na 2 B 4 O 7 · 7H 2 O 5~10g / l NH 4 VO 3 2~10g / l NaVO 3 2~10g / l Na ₂ SO _{4 5 to} 10 g / l The preparation method is the same as the above (1). Process conditions: pH = 3-6, current i = 0.5-5A / dm ² , V = 150-350
V, solution temperature 10-35 ° C, oxidation time t = 5-20 minutes. There are two types of products produced by this process: a film having a color point and a film having a uniform color. The features of the process are the same as in (2) above. Using two different stirring methods, films having different effects of light brown to brown to black are obtained. The film thickness is 5
1515 μm.

(6) a pale yellow ~ yellow film _{composition: (NaPO 3) 6 10~50g /} l Na 2 B 4 O 7 · 7H 2 O 5~10g / l NH 4 VO 3 2~7 g / l NaVO 3 2~ 7 g / l Ni (Ac) 2 5~15g / l MnSO 4 1~5 g / l H 3 BO 3 5~10g / l preparation method is the same as above (1). Process conditions: pH = 3-7, current i = 0.5-5A / dm ² , V = 150-300
V, time t = 5-15 minutes, temperature 10-30 ° C. There are two types of products produced by this process, a film having a uniform surface color and a decorative film having color points of different sizes. As in the case of the above (2), such an effect is produced mainly by a different stirring method. The color of the film is light yellow to yellow to deep yellow. The thickness of the film is between 5 and 20 μm.

(7) bronzite color film _{composition: (NaPO 3) 6 10~50g /} l Na 2 B 4 O 7 · 7H 2 O 10~15g / l Na 3 PO 4 · 12H 2 O 10~15g / l NH 4 VO 3 1-10 g / l Na ₂ CrO ₄ 2-10 g / l pH = 6-10.5. The preparation method is the same as the above (1). Process conditions: current i = 0.5 to 10 A / dm ² , V = 150 to 350
V, time t = 5-20 minutes, temperature 10-50 ° C. The thickness of the film is 5-1
5 μm. The color of the film is light copper to deep copper.

(8) Gray film _{composition: (NaPO 3) 6 10~50g /} l Na 2 B 4 O 7 · 7H 2 O 10~15g / l Na 2 SO 4 5~10g / l Na 3 PO 4 · 12H 2 O _{10~15g / l CoSO 4 · H 2} O 2~15g / l Cr 2 (SO 4) 3 2~15g / l Co (Ac) 2 2~10g / l Ni (Ac) 2 · H 2 O 2~10g / l NH ₄ VO _{3 2 to} 10 g / l The preparation method is the same as the above (1). Process conditions: current i = 0.5-10 A / dm ² , V = 125-350 V, temperature 20-5
0 ° C., oxidation time t = 5-20 minutes. There are two types of products: light gray to deep gray, uniform color films, and gray films having a color point on the surface. The stirring method is the same as in the above (2). The thickness of the film is between 5 and 20 μm.

(9) ceramic film composition of the _{hard: (NaPO 3) 6 10~50g /} l H 2 SiF 6 2~20g / l KF 1~10g / l Na 2 B 4 O 7 · H 2 O 7~20g / l Na ₂ WO _{4 1~20g} / l preparation method is the same as above (1). Process conditions: current i = 1-15A / dm ² , V = 100-200V, solution temperature 10
~ 30 ° C, oxidation time 5-25 minutes. The stirring process uses forced homogeneous stirring. The aluminum alloy film is deep gray and the thickness of the film is 10-100 μm.

By using any two of the above solutions in combination other than the above various products, films of various colors can be obtained. For example, from the white magnetic film obtained by using the solution of (1), a stirring method for obtaining the color point described in (2) above is used to prepare a white substrate in the solution of (2). A product having a blue dot is obtained. See the examples for specific methods.

3. Rinse Water temperature is 15-60 ℃. Wash without leaving any components of the solution.

4. Finishing treatment Mainly to improve glossiness, impregnated
Finishing of the surface is performed by a coating method such as pouring and spray coating. Using a paint such as a water-soluble acrylic acid or a water-soluble amino resin, a drying treatment is performed according to the requirements of the paint. In the case of water-soluble acrylic acid, the drying temperature is t =
150-250 ° C. and time is 5-30 minutes. After drying, products that have passed the inspection are packaged and finished.

The method of the present invention uses a plasma arc discharge to enhance the electrochemical reaction. The obtained film has a higher content of the substance derived from the electrolyte than the ordinary anodic oxide film, and does not contain the hydrate of the oxide of the member.

Therefore, the product obtained by the method of the present invention comprises a metal member and a ceramic film on the surface of the member. In the film, the content of the component metal oxide is 70.0 to 95.0% by weight, and the content of other metal oxides, nonmetal oxides, inorganic salts or a mixture thereof is 5.0 to 30.0% by weight. .
The ceramic film is formed by an anodic oxidation method enhanced by plasma arc discharge. Other metal oxides, non-metal oxides, inorganic salts or mixtures thereof are derived from the electrolyte.

The appearance of the film of the product of the invention is a regular inlaid deposit with very low porosity (less than 0.5%) and few macroscopic defects. The distribution of each component in the film is uniform. Since metal atoms on the surface of the member directly participate in the reaction, the bond between the film and the member is dense and has no apparent boundary.

The uniformity of the ceramic film of the product of the present invention is good, the bonding strength with the member is high, the gap is small, and the impact resistance and corrosion resistance are excellent. Further, the ceramic film of the present invention is glossy in color, has many colors and patterns, can form a design, and is extremely excellent in decorativeness. The method of the present invention comprises:
Suitable for surface treatment of members of any size, shape and structure.

 Hereinafter, the present invention will be further described through examples.

BEST MODE FOR CARRYING OUT THE INVENTION Example 1 1000 ml of distilled water was added to a 1.5-liter oxidation vessel, and 35
was added g of (NaPO _{3) 6,} sufficiently dissolved, adding borax in 10.5 g, was added to sodium phosphate 10 g, a pH in H ₃ PO _{4 4.}
Adjust to 5-5.0, add 5 g Ca (Ac) ₂ and prepare solution. The solution is allowed to stand for 24 hours before being subjected to the next step. 50x
A 100 × 5 mm LD31 type aluminum plate is washed with an alkaline cleaning solution, and this member is fixed with a fixture, connected to a power source, and stirred in a container. Oxidation treatment is started using stainless steel as a cathode and members as an anode. When the current is maintained at 1 A and the voltage is gradually increased to 160 to 180 V, a plasma arc discharge phenomenon occurs on the surface of the member. Voltage 210
When rising to ~ 240V, reduce the current. The oxidation time is 10 minutes. The oxidation is stopped, the current is reduced to 0, the voltage is reduced to 0, and the power is turned off. The member is taken out and a white magnetic film is obtained. After the cleaning, a finishing process is performed. The member is impregnated in a water-soluble acrylic resin and dried in a drier at 220 ° C. for 5 minutes. Removed from the dryer, the product is completed. According to the measurement, the film thickness is 10μm and Vickers hardness (HV) is
It is 310 kg / mm ² (5 g). Abrasion resistance test: sand blasting time 300
Seconds. Cass test is 9th grade.

Example 2 1000 ml of distilled water was added into a 1.5-liter oxidation vessel, and 35
g of (NaPO ₃ ) ₆ were added and dissolved, then 10 g of H ₃ BO ₃ , 2 g
Add CoSO ₄ , 2 g EDTA. After dissolving, allow to stand for 24 hours, and use for the next step. Oxidation is performed using the method of Embodiment 1 to obtain a member having a white magnetic color film. After the cleaning, the member is placed in an oxidation container, the solution is left standing, and electricity is applied to perform oxidation. Current is 0.7 A / dm ^2, holding the 1.5 min,
The member is then moved (or the solution is agitated) to cause less arcing on the surface. After holding this step for one minute, the oxidation is stopped and the power is turned off. The member is taken out, and a member having a blue color point on a white base is obtained. After finishing and polishing the parts,
The finished product is obtained.

Example 3 In an industrial oxidation container having a length of 7.2 m, a width of 1.6 m and a height of 2.3 m
Of water was added 20000 kg, was added (NaPO _{3) 6} of 700 kg, after sufficiently dissolving vigorous stirring, 140 kg of Na ₂ B ₄ O ₇ · 7H
Add ₂ O, 100 kg of NH ₄ VO ₃ and 200 kg of Na ₂ SO ₄ . After completion, leave for 24-48 hours. This oxidation vessel is provided with a cold water cooling facility, and keeps the vessel temperature at 15 to 35 ° C. Stainless steel is used as the cathode. Aluminum alloy building components (6063
(Type) According to the measurement, 15 pieces (the area per piece is 180 dm ² , and the total area of 15 pieces is 180 × 15 = 2700 dm ² ) is placed in the washing container and immersed for 25 minutes. Take up in the traveling hoist,
After the water has been inverted, it is placed in a rinsing container, removed and placed in a second rinsing container and then in an oxidizing container. Check the connection with the power supply, and if there is no problem with the fixture, energize to start oxidation. Using a current of 1A / dm ^2,
The voltage is gradually increased, the solution is agitated and the cooling system is activated. When the voltage rises to 150V, arcing light is generated on the surface of the member. Keeping the above process conditions, the oxidation time is 10 minutes and the final voltage is 230V. Reduce current, disconnect power, pick up components, invert water,
Place in rinse container, then rinse. It penetrates into a resin container and is finally dried in a drying oven. After taking it out, it is packed and finished. As a result of the inspection, the color was brown, and the thickness of the film was 8 to
11 μm, and the appearance is uniform. Vickers hardness (H
V) is 260 to 480 kg / mm ² (0.049N). Abrasion resistance test: 300-500 sec.

Example 4 1000 ml of distilled water was placed in a 1.5 L oxidation vessel, and 25 g of N
_{a 3 PO 4 · 12H 2 O} , 7g of _{Na 2 B 4 O 7 · 7H} 2 O and 10g of Na ₂ SiO ₃
And completely dissolved, and then left for 24 hours. Stainless steel is used as the cathode. 50 × 100 × 1mm titanium alloy (TAI
After washing the mold, put it in an oxidation container and perform oxidation.
When i = 3 A, the voltage starts to rise and reaches 100 V, light of a small arc discharge is generated on the surface. Oxidation time to 15 minutes,
Then, the voltage is controlled to 150V. Thereafter, the current is reduced and the power is turned off. Remove components and rinse. After drying, the color of the sample membrane is gray. By measurement, the film thickness is 15μm
It is. Cass test is 9th grade.

Example 5 100 kg of distilled water was placed in an oxidation vessel, and 3.5 kg of (NaPO
₃ ) After adding ₆ and completely dissolving, 1000 ml of H ₂ SiF ₆ ,
1.5kg of _{Na 2 B 4 O 7 · 7H} 2 O, 0.5kg of Na ₂ WO ₄ · 2H ₂ O and 0.2
After adding kg / l of KF and completely dissolving, the mixture is left for 24 hours and subjected to the next step. A pure aluminum plate of 150 x 100 x 10 mm is washed, fixed with fixtures, placed in an oxidation vessel and processed. The current is 15A, and when the voltage gradually increases and reaches 100V, plasma arc discharge occurs. The voltage rises very slowly, controlling the time to 20 minutes and the final voltage to 180V. Thereafter, the current is reduced, the power is turned off, and the members are taken out. After rinsing and drying, it becomes a finished product. According to the measurement, the thickness of the film is 50-70 μm, the blast sand wear time is 720-800 seconds, and the Vickers hardness is 900-1300H
V (0.098N). The coupling strength with the member is 25.6-35.0k
a g / mm ^2.

The above procedure is described by way of example only, but is not intended to limit the invention in any way. Those skilled in the art can make various modifications or changes to the present invention without departing from the substantial content of the present invention and the protection scope of the claims.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-195295 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 11/02 C25D 11/06

Claims (13)

(57) [Claims] 1. A method for forming a ceramic on a surface of a metal member, the method comprising, in an electrolyte solution, performing a plasma arc discharge on a surface of the metal member as an anode through electric energy to perform electrochemical anodization; A step of forming a film having a ceramic structure, and a step of washing the member before the oxidation treatment, rinsing after the oxidation treatment, and finishing, wherein the electrolyte solution mainly includes 10 to 10 parts. It contains 50 g / l sodium hexametaphosphate, 5-20 g / l boric acid and / or borax, and further contains sodium orthophosphate, sodium sulfate, sodium silicate, ammonium metavanadate, sodium metavanadate, sodium chromate,
At least one selected from the group consisting of oxygen-containing salts of sodium tungstate, cobalt sulfate, nickel sulfate, iron sulfate, manganese sulfate, and chromium sulfate, and optionally, calcium, zinc, cobalt and nickel acetate , fluorosilicic acid, potassium fluoride, and contains an additive selected from the group consisting of ethylenediaminetetraacetic acid; and the voltage of the arc discharge is 100 to 400, current density, 0.5~20A / dm ² And the temperature of the electrolyte solution is
10-50 ° C. 2. The composition of the electrolyte solution comprises 10 to 50 g / l sodium hexametaphosphate, 10 to 30 g / l sodium phosphate, 5 to 20 g / l borax, 0.1 to 5 g / l calcium acetate, 0.
1-10 g / l sodium silicate, 0.1-12 g / l zinc acetate,
5-10 g / l sodium sulphate and 5-20 g / l boric acid; pH between 4.0 and 10.5;
2. The method according to claim 1, wherein the voltage is between 100 and 400V. 3. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 5 to 20 g / l boric acid, 1 to 6 g / l.
Ethylenediaminetetraacetic acid, 5-10 g / l sodium sulfate, 5-15 g / l sodium phosphate, 5-20 g / l cobalt sulfate, 1-10 g / l nickel sulfate, and 10-20 g / l acetic acid 2. The method of claim 1, wherein the pH is 4.0-6; and the voltage of the arc discharge is 150-300V. 4. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 5 to 10 g / l sodium phosphate, 5 to 10 g / l boric acid, 2 to 15 g / l nickel acetate. , 5
~ 10 g / l sodium sulfate, 5-10 g / l borax, 2-10 g / l
2. The method according to claim 1, wherein 1 l of iron sulphate, 1 to 6 g / l of ethylenediaminetetraacetic acid and 2 to 10 g / l of manganese sulphate; and the voltage of the arc discharge is 125 to 350 V. 5. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 5 to 20 g / l borax, 10 to 30 g / l sodium phosphate, 0.5 to 10 g / l sodium silicate. , 0.
1 to 12 g / l zinc acetate, and 5 to 20 g / l manganese sulfate; and the arc discharge voltage is 150 to 350 V,
The method of claim 1. 6. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 5 to 10 g / l borax, 2 to 10 g / l ammonium metavanadate, 2 to 10 g / l sodium metavanadate. And 5-10 g / l sodium sulfate; the pH is 3-6; and the arc discharge voltage is 150
The method of claim 1, wherein the voltage is ~ 350V. 7. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 5 to 10 g / l borax, 2 to 7 g / l ammonium metavanadate, 2 to 7 g / l sodium metavanadate. 5-15 g / l nickel acetate, 1-5 g / l manganese sulphate, and 5-10 g / l boric acid;
The method of claim 1, wherein the voltage of the arc discharge is 150-300V. 8. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 10 to 15 g / l borax, 10 to 15 g / l sodium phosphate, 1 to 10 g / l ammonium metavanadate. And the voltage of the arc discharge is 150-350V. And the method of claim 1, wherein the voltage of the arc discharge is 150-350V. 9. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 10 to 50 g / l borax, 5 to 10 g / l sodium sulfate, 10 to 15 g / l sodium phosphate, 2 to 1
5 g / l cobalt sulfate, 2-15 g / l chromium sulfate, 2-10 g
2. The method of claim 1, wherein the arc discharge voltage is 125 to 350 V, wherein the volume of the arc discharge is 125 to 350 V./l cobalt acetate, 2 to 10 g / l nickel acetate, and 2 to 10 g / l ammonium metavanadate. 10. The composition of the electrolyte solution is 10 to 50 g / l sodium hexametaphosphate, 2 to 20 ml / l fluorosilicic acid, 1 to 10 g / l potassium fluoride, 7 to 20 g / l borax. And the voltage of the arc discharge is 100-200V. 11. The method according to claim 1, wherein in the oxidizing step, the electrolyte solution is vigorously and uniformly stirred. 12. The method of claim 1, wherein in the oxidizing step, the electrolyte solution is vigorously and uniformly stirred, and then the stirring is stopped and re-stirring is performed suddenly or the member is moved in the solution. The method according to 10. 13. A product obtained by the method according to claim 1.