JP2006322034A - Electrode for discharge surface treatment, coated film for discharge surface treatment and treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a coated film so as to contain more materials having a solid lubrication effect, and to establish an electrode for discharge surface treatment for forming the coated film and a discharge surface treatment method. <P>SOLUTION: The electrode is used for the discharge surface treatment which forms the film coated with a substance formed by a reaction of a coating film of an electrode material or the electrode material due to the discharge energy, on the surface of an article to be treated, which has been generated by the steps of; preparing a compact formed from a metallic powder or a powder of a metallic compound, or a heated compact formed of the above compact which has been further heat-treated; using the compact as the electrode; placing it in oil; and applying pulsed voltage between the electrode and the article to be treated. The electrode includes any material selected from among MoS<SB>2</SB>, WS<SB>2</SB>, NbS<SB>2</SB>, MoSe<SB>2</SB>, WSe<SB>2</SB>, NbSe<SB>2</SB>, hBN, graphite, fluorinated graphite or the like, which have a solid lubricating function, in an amount of 2 to 40 wt.%, and any material selected from among Mo, W, Ti, Fe, Mo alloy, W alloy, Ti alloy, Fe alloy or the like, which easily react with carbon, with respect to the material having the solid lubricating function. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a molded body obtained by molding a metal powder or a metal compound powder, or a powder molded body obtained by heat-treating a molded body of the powder as an electrode between an electrode and a workpiece in an oil processing liquid. The present invention relates to a discharge surface treatment in which a pulsed discharge is generated, and a film made of an electrode material or a material obtained by reacting the electrode material with the discharge energy is formed on the surface of the workpiece by the energy.

As a technique for forming a coating film of a solid lubricant by using electric discharge, for example, as shown in International Publication WO00 / 29157, in a working fluid such as water not containing carbon, a discharge electrode and a workpiece surface In this manner, a pulsed discharge is generated, and an electrode consumable molten material of the discharge electrode generated by the discharge energy is deposited and deposited on the surface of the workpiece to form a film having a lubricating action.
In other words, since the treatment is performed in a machining fluid that does not contain a carbon component, the material of the discharge electrode that has a solid lubrication action does not change into a compound with carbon or the like, and remains attached to the surface to be treated as a material having a solid lubrication action It was deposited and a film having lubricity could be formed on the surface of the workpiece.
Japanese Patent No. 3227454 discloses a method for producing a coating containing the above materials by mixing Mo, Cr, and hBN as solid lubricants in an electrode and generating discharge in oil.

International Publication WO00 / 29157 Japanese Patent No. 3227474

In the coating treatment shown in Patent Document 1, since electric discharge is generated in water, when voltage is applied between the electrode and the workpiece, water is electrolyzed to generate oxygen at the anode and hydrogen at the cathode.
Therefore, when the electrode melted substance in a high energy state due to discharge is exposed to oxygen generated by electrolysis, the surface is oxidized, and the high energy state of the electrode consumable molten substance is maintained by the exothermic reaction of oxidation. Then, oxidation proceeds to the inside of the electrode consumable molten material.
Therefore, the electrode consumable molten material containing a large amount of the oxide adheres to and deposits on the workpiece. However, since the oxide does not have the desired lubricity, the film has insufficient lubricity.
The film including the self-lubricating function shown in Patent Document 2 exhibits its effect at a high temperature exceeding 680 ° C., but does not exhibit low friction in a temperature range from room temperature to about 300 ° C., and the counterpart material has a Vickers hardness of 30 HV to 300 HV. If it is about, it will be severely worn.

  The present invention aims to form a film containing a larger amount of a substance having a solid lubricating action, and establishes a discharge surface treatment electrode and a discharge surface treatment method for forming the film.

An electrode for discharge surface treatment according to the present invention uses a molded body obtained by molding a metal powder or a metal compound powder, or a heated molded body obtained by heat-treating this molded body as an electrode. It is used in the discharge surface treatment in which a pulsed discharge is generated between the workpiece and the surface of the workpiece is formed with a coating of the electrode material by the energy of the discharge or a coating of the material with which the electrode material has reacted by the energy of the discharge. 2-40 wt% of any material such as MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , hBN, graphite, graphite fluoride and the like having a solid lubricating action, Any of Mo, W, Ti, Fe, Mo alloy, W alloy, Ti alloy, Fe alloy and the like that easily reacts with carbon with respect to the material having the above solid lubricating action It is those that contain the material.

  The electrode for electrical discharge surface treatment according to the present invention can form a film containing a larger amount of a substance having a solid lubricating action and having a low wear amount and a low friction coefficient.

Embodiment 1 FIG.
First, the principle of the discharge surface treatment will be described.
Molded powder of metal, alloy of metal alloy and powder of substance having solid lubricating action, or molded and heat-treated and used as electrode, processing filled with petroleum processing fluid Disposed between the base material (workpiece) placed on the cage and spaced apart by a predetermined gap, the electrode is the cathode, the work piece is the anode, and the spindle is servoed so that they do not come into contact with each other, and a discharge occurs between them. Let
The workpiece and the electrode are melted and vaporized by the heat of discharge, and a part of the melted electrode (molten particles) is transported to the workpiece surface by the blast and electrostatic force generated by the vaporization.
When a part of the melted electrode reaches the surface of the workpiece, it resolidifies and becomes a coating.

Next, the process for manufacturing the electrode for discharge surface treatment in the present embodiment will be described with reference to FIG.
In the present embodiment, Mo (molybdenum) powder having an average particle diameter of 1 μm is used as an electrode material by weight ratio of 80 wt% and 20% by weight of MoS ₂ (molybdenum disulfide) powder having an average particle diameter of 4 μm. .
First, in order to suppress agglomeration of the powder and the powder, the Mo powder that is a metal powder and the MoS2 powder having a solid lubricating action are sealed in a cylindrical container in accordance with a highly volatile organic solvent that is at least twice the powder volume. Then, the cylindrical container is rotated for several hours to several tens of hours to uniformly mix the Mo powder and the MoS ₂ powder.
Here, if the mixing time is too short, a portion where a powder having a solid lubricating action is present and a portion where the powder having a solid lubricating action is present are generated, and a portion having no solid lubricating action is also formed in a film formed using the powder. Since there is a problem that wear proceeds from there, it is necessary to mix so that the powder after mixing does not appear patchy.

When mixing is completed, the mixed powder is allowed to settle at the bottom of the container by allowing it to stand for a while.
Then, the supernatant liquid is gently removed into another container so that the settled powder does not rise, and only the mixed powder slightly containing the organic solvent is taken out.
Thereafter, the mixed powder is dried in a vacuum furnace or a normal temperature atmosphere to volatilize the organic solvent.
Furthermore, since the dried powder is aggregated to form a large mass, it is passed through a sieve having a mesh size of 100 μm to 300 μm to decompose the aggregated mass.
This mesh size is determined from the formability of the press in the subsequent process and the size that can be pulverized by the explosive force of discharge when it falls between the electrode and the base material during processing.

Next, the mixed powder is put in a predetermined mold, and pressure is applied by a punch and pressing is performed, whereby the mixed powder is hardened and becomes a green compact.
Here, if wax such as paraffin is mixed in the powder by about 1% to 10% by weight, the pressure of the mixed powder can be transmitted to the inside of the mixed powder during pressing, and the moldability can be improved. The mixture was mixed and compression molded at a press pressure of 200 MPa.

The compression-molded green compact can be used as it is as an electrode for discharge surface treatment as long as a predetermined hardness is obtained by compression, but if it has high resistance and is not conductive, it can produce a coating. Therefore, it is necessary to improve the electrical conductivity by heating and promoting the bonding between the particles.
Further, when wax is used during pressing, it is necessary to remove the wax from the green compact, and the wax is removed by heating to a temperature higher than the melting point of the wax.
In the present embodiment, after compression molding, a 50 × 16 × 3 electrode was molded by holding in a vacuum furnace at about 860 ° C. for one hour.

Next, processing conditions for forming a film on an Al alloy (A5052) as a workpiece using this electrode will be described.
FIG. 2 is a diagram showing a current waveform in the present embodiment.
As shown in the figure, by supplying a large current of about 15 A to 60 A within 2 μs immediately after the start of discharge, the explosive force and heat generated by the discharge are greatly increased, and the electrode is heated rapidly. The material is melted and supplied to the workpiece side, and a melted area where the workpiece surface is melted is also formed on the workpiece.
For workpieces with a high thermal conductivity such as Al, the processing conditions such as this current waveform are preferred because the heat generated by the discharge escapes into the workpiece.
In addition, when a fusion zone cannot be formed on a to-be-processed object, the adhesive strength of a film will reduce and it will become a film which peels easily.

Next, the discharge is continued for several μs to several tens of μs with the current rapidly reduced from about 2 A to about 15 A, and the melting region is maintained with the heat generated by the discharge current, and the electrode material is melted with the small current, Move and deposit on the workpiece.
Although the film can be formed even if the current value is increased to 20 A or more, the surface roughness of the film formed with a large current value exceeds 50 μm in Ry, and post-processing such as polishing becomes difficult. The following current values must be used:

In this embodiment using a mixed electrode of Mo and MoS ₂ , after supplying a peak current of 50 A and a discharge time of 1.5 μs, processing is performed under a discharge condition of a discharge duration of 64 μs and a rest time of 1024 μs with the current dropped to 11 A. It was.
The treated surface of the workpiece was treated for about 60 minutes in a machining liquid mainly composed of kerosene while moving the electrode, thereby forming a 50 × 15 × 0.1 coating.

A cross-sectional photograph of the coating is shown in FIG.
The cross section was not filled with resin, but was cut into two parts with a cutting machine, polished in the order of polishing paper Nos. 600, 1000 and 1500, and finally finished with a diamond paste of 2 μm.
Considering from the figure, it is considered that there is no clear boundary between the workpiece and the coating, and the coating and the workpiece are diffusion bonded.
Further, as a result of binarization image processing, voids with a porosity of about 30% are present inside the coating.

Next, the test results of the friction coefficient and the wear amount of the coating will be described.
In the test of the friction coefficient and the amount of wear, a pin made of R18 alloy tool steel SKS was reciprocated on the coating with a test load of 30 MPa, a maximum speed of 3 m / s, and an amplitude of 40 mm to obtain the coefficient of friction and the amount of wear. .
As a result of the sliding test for about 2 hours, the friction coefficient was 0.2 and the wear amount was 5 μm, and both the wear amount and the friction coefficient were low.
The friction coefficient of solid lubrication in which metals are in contact with each other is 1 or more. When solid lubrication occurs under the above sliding conditions, seizure occurs and pins and coatings are worn by several mm or more.
However, if the friction coefficient is about 0.2, seizure does not occur and wear hardly occurs.
A film with such a wear amount and coefficient of friction is subject to wear in areas where a large load is applied locally in the environment where the lubricant is used, causing the lubricant film to break and cause seizure, or where the lubricant cannot be used. Can be suppressed.
Such a part is preferably applied to the field of a contact portion with a cam of a reciprocating mechanism using a bearing or a cam.

Next, the identification result of the substance on the surface of the film by X-ray analysis is shown in FIG.
On the surface of the film, there is a small peak of Mo ₂ C (molybdenum carbide) in addition to Mo and MoS ₂ contained in the electrode, and it can be seen that Mo ₂ C was slightly present.
Considering the reason for the presence of MoS ₂ , the oil is decomposed by the heat of the discharge by generating a discharge in a working fluid made of an organic substance such as oil, and methane and carbon are generated between the electrode and the workpiece.
And it is guessed that Mo in the electrode consumable molten material melted by discharge reacts with carbon in the carbon or methane and Mo ₂ C is formed by reaction.
In addition, a part of MoS ₂ which is the same electrode material is also decomposed, and the Mo is carbonized. However, in the case of MoS ₂ , since energy for decomposition with S (sulfur) is further required, the single metal of Mo is As a result of requiring more energy than carbonization, Mo carbonization is prioritized and the carbonization of MoS ₂ having a solid lubricating action can be suppressed.
Further, Mo ₂ C appearing as a result of the substance identification is a substance having a strength exceeding Vickers hardness of 1500 HV.
Therefore, if Mo ₂ C is present in the coating, its hardness can contribute to an improvement in the wear resistance of the coating.

Next, the ratio of the content of MoS ₂ contained in the electrode will be described.
MoS ₂ is because it is a material having a solid lubricating effect, when the content of MoS ₂ in the electrode, the coefficient of friction increases the content of MoS ₂ in the film is reduced to about 0.2.
However, since MoS ₂ is a sublimation type material, it cannot melt and become a film.
As a result of the experiment in the present embodiment, when the ratio of the substance having the solid lubricating action exceeds 40 wt% in the mixed electrode of the metal such as Mo or W and the substance having the solid lubricating action such as MoS ₂ or WS ₂ , It was found that the amount of MoS ₂ was about 80% in the volume of the formed film, and the particles forming the film could not be bonded to each other and the film was easily peeled off by hand.
Further, if the ratio of the material having a solid lubricating action such as MoS ₂ or WS _{2 of the} electrode is less than 2 wt%, the ratio of the substance having a solid lubricating action such as MoS ₂ or WS ₂ contained in the film is also reduced, and the friction is reduced. The coefficient becomes about 0.7.
If the friction coefficient is further increased, seizure may occur. Therefore, in order to form a film that suppresses seizure, the ratio of the substance having an action in the solid contained in the electrode is 2 wt% or more and 40 wt% or less. It is necessary to.

Moreover, the porosity of the film formed on the same discharge conditions becomes large, so that the ratio of the substance which has a solid lubrication effect | action of an electrode increases.
A substance having a solid lubricating action such as MoS ₂ or WS ₂ is present in the coating in a state surrounded by a metal such as Mo or W.
Here, the bonding strength of the particles constituting the coating is determined by the metal bonding state of Mo or W, and MoS ₂ is present in a floating state in the molten metal, so MoS ₂ or WS _{If a} large amount of ₂ exists, the bonding area of Mo and W decreases, and the bonding strength decreases.
This decrease in bond strength generates many portions that are detached from the coating in the cutting process for observing the cross section of the coating, resulting in a coating with a large porosity.
FIGS. 5 and 6 show cross-sectional photographs of the film when the amount of MoS ₂ is 40 wt% and when it is 5 wt%.
From experiments, the porosity of the coating is about 80% when the ratio of the substance having a solid lubricating action is about 40 wt%, and the porosity is about 5% when the ratio of the substance having a solid lubricating action is 2 wt%.

In general, a coating film with a high porosity has a small shearing force and can reduce the friction coefficient, but it collapses when a large frictional force acts.
On the other hand, a film with a low porosity has a large shearing force and a high friction coefficient, but it does not collapse even with a large frictional force.
Further, the friction coefficient depends on the content of MoS ₂ or the like acting on the porosity, and when the friction coefficient is about 1, seizure tends to occur.
Therefore, as a coating having a friction coefficient of 0.1 to 0.5 and a wear amount of several μm used for a bearing or the like, a material having a solid lubricating action such as MoS ₂ and WS ₂ in the electrode is made ₂₀ Wt%, Mo It is preferable that the metallic substance of W or W is 80 wt%.

The above relationship is shown in the table below.
This relationship is obtained when a coating is formed under the above-described processing conditions on an Al alloy workpiece using a green compact electrode made of Mo powder having an average particle diameter of 1 μm and MoS ₂ powder having an average particle diameter of 4 μm. This is experimental data.

なお、本実験では、Ｍｏ粉末とＭｏＳ_２粉末の圧粉体電極についてのデータであるが、固体潤滑作用を有する材料としては、ＷＳ_２（二硫化タングステン）粉末とＷ粉末との混合粉末の圧粉体電極においても同様の実験データを得た。

In this experiment, it is data on the green compact electrode of Mo powder and MoS ₂ powder. As a material having a solid lubricating action, the pressure of the mixed powder of WS ₂ (tungsten disulfide) powder and W powder is used. Similar experimental data were obtained for the powder electrode.

According to the embodiment of the present invention, when a substance having a solid lubricating action is formed in the coating film by including a substance having a solid lubricating action in the discharge surface treatment electrode, the solid lubricating action is obtained. By including in the electrode a substance that is more easily carbonized than the material, carbonization of the substance having a solid lubricating action can be suppressed, and a film sufficiently including the substance having a solid lubricating action can be formed.
In addition, the metal for suppressing carbonization of the substance having a solid lubricating action is carbonized to increase the strength, and the wear resistance of the coating can be improved.
Also, by using a discharge waveform that becomes a high peak immediately after the start of discharge and then continues a small current, a film containing a substance having a solid lubricating action is formed on a workpiece having a high thermal conductivity such as Al. it can.

  By changing the ratio of the substance having a solid lubricating action and the substance that is more easily carbonized than the substance having the solid lubricating action, the friction coefficient and the amount of wear can be adjusted, and the frictional force acting on the film By selecting a coating film with a low porosity when the frictional force is large and selecting a coating film with a high porosity when the frictional force is small, a coating with low friction and low wear that meets the required specifications can be realized.

In the embodiment described above, the substance having a solid lubricating action has been described in the case of MoS ₂ , but WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, and graphite fluoride having the same layered lattice structure. However, since the friction form is the same, a low friction film can be formed.
In addition to Mo and W, Ti, Fe, Mo alloy, W alloy, Ti alloy, and Fe alloy may be used as the metal that has a small generation entropy with carbon and is easily carbonized.

Embodiment 2. FIG.
In the first embodiment described above, by forming a green compact electrode in which a material having a solid lubricating action and a material that is more easily carbonized than the material having the solid lubricating action are mixed, the material that is easily carbonized has a solid lubricating action. This embodiment uses a chemical change that suppresses carbonization of the material. In this embodiment, the solid lubricating action of carbon is achieved by mixing a material having a solid lubricating action and a material that solidifies a large amount of carbon. The supply to the material which has is prevented.

In the present embodiment, a Co (cobalt) powder having an average particle diameter of 1 μm and a 20% MoS ₂ powder in a weight ratio are mixed and dried, and then a wax is mixed by 3% by weight and compression-molded at 200 MPa. Holding in a vacuum furnace at about 300 ° C. for 1 hour, a 50 × 16 × 3 electrode was formed.
Then, using a mixed electrode of Co powder and MoS ₂ powder, a peak current of 50 A and a discharge time of 1.5 μs were supplied onto aluminum 4032, and then processing was performed under a discharge condition of a discharge duration of 8 μs with the current dropped to 11 A.
The processing surface of the work piece is 50 × 3, and the electrode is moved on the processing surface, and is processed for about 60 minutes in a processing liquid mainly composed of kerosene, so that the thickness of the Al alloy (A5052) is 0. A 1 mm film was formed.
In this embodiment, since Co has a lower melting point and lower heat of melting than Mo, the electrode can be melted in a shorter discharge duration.
Therefore, the discharge duration can be made shorter than in the first embodiment.

Co does not react with carbon, but can dissolve carbon in a large amount.
In other words, when a discharge is generated in a machining fluid composed of an organic substance such as oil, the oil is decomposed by the heat of the discharge, and methane and carbon are generated between the electrode and the workpiece. The purpose of the present embodiment is to reduce the amount of carbon that reacts with a substance having a solid lubricating action and to suppress carbonization of MoS ₂ and WS ₂ that are substances having a solid lubricating action.

A cross-sectional photograph of the formed film is shown in FIG.
The cross section was not filled with resin, but was cut into two parts with a cutting machine, polished in the order of polishing paper Nos. 600, 1000 and 1500, and finally finished with a diamond paste of 2 μm.
Considering the figure, there is no clear boundary between the workpiece and the coating, and it is considered that the coating and the workpiece are diffusion bonded.
Further, as a result of image processing by binarization, voids with a porosity of about 20% are present inside the coating.

Compared with Embodiment 1 using Mo or W, the porosity decreased slightly when Co powder that did not react with carbon was used.
Mo and W react with carbon to form carbides such as Mo ₂ C and WC.
These carbides have a very high melting point of about 4000 K, and in the process of solidifying the film, they are precipitated before the metal such as Mo and W, and the surroundings are surrounded by the metal like MoS ₂ and WS ₂ . It will be present in the film in a state.
Therefore, if carbide is included in the coating, the carbide has a high strength and thus has an effect of suppressing the amount of wear, but it reduces the bond strength of the particles constituting the coating, and is a part that falls off during cross-section preparation. Is likely to occur, and the porosity is increased.
On the other hand, since Co does not form carbides, it is possible to increase the bond strength between the particles constituting the coating and to reduce the porosity as compared to Mo and W.
That is, it is effective to apply the present technology to a coating used in an environment where a larger frictional force acts than a coating made of Mo and MoS ₂ .

Next, the test results of the friction coefficient and the wear amount of the coating will be described.
In the test of the friction coefficient and the wear amount, an R18 alloy tool steel SKS pin was slid back and forth on the coating with a test load of 100 MPa, a maximum speed of 6 m / s, and an amplitude of 40 mm to obtain the friction coefficient and the wear amount.
As a result of the sliding test for about 2 hours, the friction coefficient is 0.2 and the wear amount is 7 μm. Compared to the case of solid lubrication of metal and metal, both the wear amount and the friction coefficient are low, and the coating can suppress seizure. Got.
A film having such a wear amount and a friction coefficient is preferably applied to the field of a contact portion with a cam of a reciprocating mechanism using a bearing or a cam.

According to the embodiment of the present invention, when a substance having a solid lubricating action is included in the discharge surface treatment electrode, a carbon having a solid solution is formed when the film of the substance having the solid lubricating action is formed on the film. By including an easy-to-use substance in the electrode, carbonization of the substance having a solid lubricating action can be suppressed, and a film sufficiently containing the substance having a solid lubricating action can be formed.
Moreover, since the bond strength between the particles constituting the coating can be increased, it is possible to provide a coating that can be used in an environment where a high frictional force acts.
Also, by using a discharge waveform that becomes a high peak immediately after the start of discharge and then continues a small current, a film containing a substance having a solid lubricating action is formed on a workpiece having a high thermal conductivity such as Al. it can.

In the present embodiment, Co powder has been described as a material that can more easily solidify carbon than a substance having a solid lubricating action. However, Ni, Co alloy, Ni alloy may be used, and these solid lubricating actions are provided. A material that dissolves carbon more easily than a substance may be contained in an amount of 30 wt% or more.
However, if the ratio of MoS ₂ is 40 wt% or more, the amount of MoS ₂ is about 80% in the volume in the formed film, and the particles forming the film cannot be bonded to each other and easily peeled off. It is necessary to make the material that easily dissolves carbon into 60 wt% or more.

This is a process for manufacturing an electrode for discharge surface treatment. It is a figure which shows the current waveform in this Embodiment. It is a figure which shows the cross-sectional photograph of a film. It is a figure which shows the substance identification result in a film surface by X-ray analysis. Is a diagram showing a film cross-sectional photograph of the case of the MoS ₂ content to 40 wt%. The MoS ₂ content is a diagram showing a film cross-sectional photograph of the case of the 5 wt%. It is a figure which shows the cross-sectional photograph of a film.

Claims (8)

A molded body formed by molding a metal powder or a metal compound powder, or a heated molded body obtained by heat-treating this molded body is used as an electrode, and a pulsed discharge is generated between the electrode and the workpiece in oil. An electrode used in a discharge surface treatment that forms a film of an electrode material on the surface of the workpiece by the energy of the discharge or a film of a substance that the electrode material reacts on the surface of the discharge,
2-40 wt% of any material such as MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, and fluorinated graphite having a solid lubricating action,
An electrode for discharge surface treatment containing any material such as Mo, W, Ti, Fe, Mo alloy, W alloy, Ti alloy, and Fe alloy that easily reacts with carbon with respect to the material having a solid lubricating action. A molded body formed by molding a metal powder or a metal compound powder, or a heated molded body obtained by heat-treating this molded body is used as an electrode, and a pulsed discharge is generated between the electrode and the workpiece in oil. An electrode used in a discharge surface treatment that forms a film of an electrode material on the surface of the workpiece by the energy of the discharge or a film of a substance that the electrode material reacts on the surface of the discharge,
2-40 wt% of any material such as MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, and fluorinated graphite having a solid lubricating action,
An electrode for discharge surface treatment containing any material such as Co, Ni, Co alloy, Ni alloy and the like that easily solidify carbon. A material such as MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, and graphite fluoride having a solid lubricating action is characterized by using a powder material having an average particle diameter of 2 μm to 10 μm. The electrode for discharge surface treatment according to claim 1 or 2. Using a molded body obtained by molding a metal powder or metal compound powder, or a heated molded body obtained by heat-treating this molded body as an electrode, a pulsed discharge is generated between the electrode and the workpiece in oil. A film formed in the discharge surface treatment for forming a film of the electrode material by the energy of the discharge or a film of a substance reacted with the electrode material by the energy of the discharge on the surface of the workpiece,
MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, graphite fluoride, etc. having a solid lubricating action are contained 2% to 40%, and the porosity is 5% to 70%. Discharge surface treatment coating characterized.   The discharge surface-treated film according to claim 4, wherein the film has a Vickers hardness of 500 HV to 1500 HV. A molded body obtained by molding a metal or a compound of metal and a powder such as MoS ₂ , WS ₂ , NbS ₂ , MoSe ₂ , WSe ₂ , NbSe ₂ , graphite, and graphite fluoride having a solid lubricating action, or this molded body Using the heated molded body that has been heat-treated as an electrode, in the oil, a pulsed discharge is generated between the electrode and the workpiece, and the electrode material reacts due to the coating of the electrode material or the energy of the discharge. In discharge surface treatment to form a coating of the material on the workpiece surface,
A material with a thermal conductivity of 100 W / mK or more made of aluminum or copper is used for the work piece, a triangular waveform current is supplied immediately after the start of discharge, and then the discharge is maintained at a current lower than the peak of the triangular waveform. A discharge surface treatment method comprising forming a film.   7. The discharge surface treatment method according to claim 6, wherein a current having a triangular waveform is supplied at about 15 A to 60 A for 2 μs or less, and a subsequent current is supplied at about 2 A to about 15 A for several μs to several tens of μs.   The metal or compound of the metal mixed with the powder having a solid lubricating action is Mo, W, Ti, Fe, Mo alloy, W alloy, Ti alloy, Fe alloy which easily reacts with carbon with respect to the material having the solid lubricating action. A discharge surface treatment method characterized by using any material such as Co, Ni, Co alloy, or Ni alloy that easily solidifies carbon.

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