JPH05148615A - Treatment for surface of metallic material - Google Patents

Abstract

PURPOSE:To inexpensively form a rigid coated layer with a sufficient thickness free from defects such as dimensional changes, deterioration in the hardness (strength) of a base metal and film peeling caused by holding the temp. of the whole body of the metallic materials of a base metal to a high one. CONSTITUTION:The surface of a base metal constituted of metallic materials is coated with metallic or nonmetallic materials. After that, the deposits are remelted for each minute area by pulse electric discharge machining in liq., gas or vacuum, by which the base metal and the coated materials, are diffused and mixed to form a dense coated layer on the surface of the base metal. As the coating materials, metals, alloys, nonmetallic elements, ceramics, carbides, nitrides, borides or the like are used. As the coating means for the coating materials, a thermal spraying method, an electrodepositing method, a low temp. depositing method, a discharge precipitating method using an electrode easy to consume or the like are used. As for the pulse electric discharge machining, it is executed preferably by using an electrode hard to consume as a minus electrode. The material called as a functionally gradient material in which the coating of the coating materials and pulse electric discharge machining are executed per layer and the coated layer is provided with gradient properties can also be manufactured.

Description

Detailed Description of the Invention

The present invention relates to a surface treatment technology for metallic materials,
More specifically, there is no problem of dimensional change or heat history of the base material,
The present invention relates to a surface treatment method for forming a dense layer having desired properties such as heat resistance, corrosion resistance, wear resistance and hardness on the surface.

[0002]

2. Description of the Related Art Conventionally, CVD (chemical vapor deposition), PVD (vacuum vapor deposition), electrodeposition, nitriding, and electroplating have been used as means for imparting wear resistance and corrosion resistance to metal surfaces. Chemical plating, electroless plating, etc. are known.

However, in both CVD and PVD, the temperature of the base material is raised to 360 ° C. or more and up to about 1100 ° C. for coating, so that the base material has a drawback that dimensional change or hardness decrease occurs widely. Are known. The hardened layer is as thin as a few μm. Further, nitriding also has a problem that the steel material is heated to about 500 ° C. to be treated.

It is well known that the surface formed by electrodeposition is easily deposited or deposited on the base material and is not diffused. Therefore, it is well known that the surface is easily peeled off, and there are drawbacks such as hydrogen embrittlement. is there. The same applies to electrochemical plating and electroless plating.

What is deposited on the surface of the base material by thermal spraying is
It is already known that it is porous and easily peeled off. Further, even if it is attempted to be re-melted by laser light, the heat input becomes non-uniform depending on the position of the spot, and streaks are generated at the boundary of the beam progress, so that a beautiful surface cannot be obtained. Further, it is structurally difficult to apply a laser beam or the like to the three-dimensional processed shape as shown in FIG.

In addition, since diffusion hardly occurs in the conventional surface treatment method, it is difficult to coat a material such as fine ceramics, which is difficult to diffuse, with a sufficient thickness (eg, several tens of μm to 100 μm).

The present invention solves the above-mentioned problems of the prior art and eliminates the drawbacks such as dimensional change, lowering of hardness (strength) of the base material, and peeling of the film, which are caused by keeping the entire metal material of the base material at a high temperature. Moreover, it is an object of the present invention to provide a surface treatment method capable of forming a strong coating layer having desired surface characteristics such as corrosion resistance and heat resistance with a sufficient thickness.

[0008]

In order to solve the above problems, the inventors of the present invention firstly conducted extensive research into a surface treatment method which does not require exposing the entire metal material to high temperatures. As a result, the coating material is deposited on the surface of the metal material by a method that does not heat the base material to a high temperature, and the deposit is microscopically remelted in a minute area and diffused into the base material. It has been found that if they can be mixed, the base material is not deformed and the hardness is not lowered, and a strong coating layer can be formed.

Then, further research was conducted on such a microscopically remelting method for deposits, and it was found that it is possible by applying pulse electric discharge machining. Electric discharge machining is a machining method that is generally well known as a machining method for removing a shape by utilizing an electric discharge phenomenon, but the present inventors microscopically remelt a deposit by the energy of electric discharge. We have developed a completely new usage.

That is, according to the present invention, after the surface of a base material made of a metal material is coated with a metal or a non-metal material, the deposit is remelted for each minute region by pulse electric discharge machining in a liquid, a gas or a vacuum. By doing so, the base material and the coating material are diffused and mixed, and a dense coating layer is formed on the surface of the base material.

The present invention will be described in more detail below.

[0012]

[Action]

As mentioned above, it is known to deposit, deposit and deposit the coating material on the surface of the metal material by thermal spraying, electrodeposition, vapor deposition or discharge deposition. The discharge deposition method is
This is a surface treatment method previously proposed by the present inventors (“199
Proceedings of the 1st Spring Meeting of the Precision Engineering Society of Japan "(1
(March 26, 991) p.463), a method of precipitating a green compact material on a counterpart metal by molding a conductive material to be deposited as a green compact and using it as an electrode for electric discharge machining. Is. However, since these deposits do not diffuse into the base material, the adhesion strength is weak.

According to the present invention, pulse discharge is applied to such a deposit by a method of electric discharge machining in a liquid, in a gas or in a vacuum, so that the average temperature of the base material is hardly increased. When a high temperature is generated locally (at the discharge point), it is remelted and diffused into the base material.

In the present invention, the means for coating the surface of the metal material with the coating material is not particularly limited, but a method in which the base material is not exposed to high temperature is recommended. For example, the above-mentioned thermal spraying method, electrodeposition method, low-temperature vapor deposition method, discharge deposition method using an electrode that easily wears, and the like can be cited, but it goes without saying that they are not limited to these. In view of the relationship with pulse electric discharge machining performed as a post process, the electric discharge deposition method is preferable.

As the coating material, various metal materials or non-metal materials can be used, and examples thereof include metals or alloys, non-metal elements, ceramics, carbides, nitrides and borides. Specifically, as hard materials, WC, TiC, Ta
It can be coated with a carbide such as C, ZrC, or SiC, a boride such as TiB ₂ , ZrB ₂ , or a nitride such as TiN or ZrN (fine ceramics) alone or in the state where a sintering aid is added. In addition, metal materials such as W and Mo, Al, Ti,
Corrosion resistant materials such as Ni, Cr and Co can also be used. Furthermore,
Even if it is not conductive like diamond, Al ₂ O ₃ and Si ₃ N ₄ , it may be coated by mixing with a conductive material such as iron powder, cobalt powder, nickel powder, chrome powder or copper powder. In short, the material may be selected according to the surface characteristics to be imparted.

After coating the surface of the metal material with the coating material,
Pulsed electrical discharge machining is applied microscopically or in small areas to remelt the deposits and diffuse and mix them into the matrix. This pulse electric discharge machining can be performed in any of liquid, gas, and vacuum, and the discharge is generated between one electrode of the deposit and the other electrode.

In the pulse electric discharge machining, it is desirable to use an electrode that is less likely to be consumed and that has a composition similar to that of the deposit. For example, when WC is mainly deposited on the surface of a metal material, a material obtained by sintering WC-Co (for example, a chip material of a bite) is used as an electrode.

The discharge is generated several hundreds to tens of thousands times per second. The processed surface is a surface on which small microscopic discharge marks are accumulated. The discharge trace current density is a very small area,
As high as tens of thousands of A / cm ² , high temperature and high pressure is in the range of 10s to 1000μ
It occurs in a short time of about s. The surface temperature at the discharge point is about the boiling point of the material, and the pressure at that point is several thousand kgf / c.
It becomes m ² , and some of the melted part is scattered, but the remaining part is remelted and diffused into the base material. Since the discharge time is short, the discharge point is immediately cooled, and the average temperature of the base material does not rise.

Preferable conditions for pulse electric discharge machining are power supply voltage: 60 to 100 V, pulse discharge current value (Ip): 1 to 1
00A, pulse width (τp): 5 to 2000 μs, rest time
(τr): 5 to 2000 μs. Generally, when the pulse discharge current value Ip is small, for example, Ip = 3A, τp
= 16μs, when Ip is large, τp =
When Ip is small like 2000τs, τp is short,
When Ip is large, τp is long.

According to the surface treatment method of the present invention, a dense layer having desired properties such as heat resistance, corrosion resistance, wear resistance and hardness is formed on the surface of a metal material such as an inexpensive steel material such as carbon steel. can do. Even if a material such as fine ceramics is difficult to diffuse into the steel material, it is possible to strengthen the diffusion and adhesion to the base material by remelting. Further, even with a material such as Al, Ti, Ni, Cr, and Co that is likely to form a solid solution with a steel material, the pulse discharge treatment enables even stronger surface treatment. That is, when high-speed discharge deposition is performed using a large current in order to increase the rate of discharge deposition, even if a material such as Al, Ti, Ni, Cr, and Co that is likely to form a solid solution with a steel material, Diffusion is insufficient, and the precipitation state becomes more uneven, but the pulse discharge treatment promotes diffusion due to remelting. Further, if the plating rate is increased at a high current density by electrodeposition or electroplating, only a rough and low-adhesion plating layer can be obtained.However, pulse electric discharge machining can form a surface layer with high adhesion. it can. Pulse discharge on non-conductive hard material such as diamond, Al ₂ O ₃ and Si ₃ N ₄ coated with conductive metal such as iron powder, cobalt powder, nickel powder, chrome powder and copper powder. When the treatment is performed, the conductive metal is remelted and the non-conductive hard material is firmly fixed to the surface of the base material.

It is also possible to manufacture a material having an inclination. The gradient material is, for example, a material in which the base material is a metal material, and the content ratio of fine ceramics gradually increases from the base material side, and the content ratio of fine ceramics is remarkably increased on the surface of the material. Such a graded material causes less shear stress and bending stress on the joint surface due to a significant difference in expansion coefficient even if the temperature rises, as compared with a material obtained by simply joining or coating a metal material and fine ceramics. Therefore, breakage and the like during use at high temperatures are less likely to occur. This is because even if thermal expansion occurs due to temperature rise, the stress is relieved.

Next, examples of the present invention will be described.

[0024]

Example 1 Al powder was compressed to form one electrode,
As shown in FIG. 1, a Fe—Al alloy layer was obtained on the surface of the base material (S50C, tempered material) by discharge precipitation. The Al powder compact is used because the apparent thermal conductivity is reduced to 1/2 to 1/3 and the strength of the electrode material is weakened when Al is used as the powder. This is because it is easy to deposit on. EDM conditions

[Table 1] Shown in.

FIG. 2 shows the results of EPMA analysis of the obtained alloy layer, and FIG. 3 shows the results of X-ray diffraction analysis. Figure 2
As a result, Al of the electrode material has an inclination (a large amount on the surface and a small amount inside), and is present on the processed surface with a thickness of 30 μm.
Further, from FIG. 3, a very strong AlFe ₃ C _{0. 5} peaks are observed. This compound is known as an intermetallic compound having excellent oxidation resistance. Thus, in the case of Al, sufficient surface treatment may be possible by discharge deposition.

However, fine ceramics (WC, Ti
C, TaC, ZrC, SiC, TiB ₂ , ZrB ₂ , TiN, Z
In many cases, it is difficult for a high melting point material such as rN), W, Mo, etc. to sufficiently diffuse into the base material only by discharge deposition. Therefore, in this example, a case where WC among them is deposited by electric discharge and pulse electric discharge machining is applied to this is shown.

First, WC powder (average particle size 3 μm) is converted to Fe powder.
(Average particle size 9.8 μm) Mix with 1: 1 ratio and compression molding
(Compression pressure 4 t / cm ² ) was applied to obtain a green compact. This was bonded to a copper round bar with a conductive adhesive to form an electrode. Then
Using carbon steel (S55C raw material) as a base material, processing conditions (Ip, τ
By changing p, τr), an electric discharge machining experiment was performed as shown in FIG.

As a result, under machining conditions where the DF (duty factor) was relatively large, arcs due to discharge were concentrated and the electrodes were destroyed, but the WC electrodes collapsed when the DF was 1.5% or less. It was consumed stably and adhered to the surface of the base metal. The processing conditions at that time are: Ip = 20A, τp =
16 μs and τr = 1024 μs.

As a result of X-ray diffraction on the sample surface after processing, a WC peak appeared as shown in FIG. As a result of measuring the adhesion amount of WC (height from the base material surface) by the depth of focus method depending on the processing time,

[Table 2] As shown in (1), by increasing the processing time, the amount of WC adhering to the surface of the base material increases. WC attached to the surface of the base material
Had a weak adhesive force and peeled off when rubbed with a driver or the like.

Next, pulse electric discharge machining was performed on the material obtained by the electric discharge machining in the following manner.

First, the WC-Co sintered body was bonded to a copper round bar with a conductive adhesive to form an electrode (finishing electrode). Then, using this finishing electrode, WC and Fe attached to the surface of the base material
Pulse electric discharge machining was performed on the deposited layer. The processing conditions are
In order to prevent the base material from being over-processed, the electrode polarity was made negative, and Ip, τp, and τr were changed, and processing was performed with the circuit configuration shown in FIG. The pulse waveform (rectangular wave) is shown in FIG. After processing,
The result of X-ray diffraction of the surface is shown in Fig. 7, and the analysis result is

[Table 3] Shown in. As shown in the table, when the pulse width (τp) is short, the current value (Ip) is high, and the processing time is long, the deposit disappears, but τp is a little long and the current value (Ip) is a little low. Under the conditions, the scattering of WC-Fe deposits could be reduced, and WC was detected.

In the electric discharge deposition, the adhesion of WC-Fe is weak as shown in FIG. 8 (cross-sectional micrograph), but when pulse electric discharge machining is applied to this, FIG. 9 (cross-sectional micrograph) and FIG. 10 (cross-sectional SEM). As shown in the photograph, it was confirmed that WC was diffused in the base material.

FIG. 11 shows the relationship between the distance from the surface and the Vickers hardness (Hc) in the cross section. The hardness of a normal WC-Co alloy is about Hv 800 to 1400, and in this experiment, the hardness of the surface treatment layer (Hv 1000 to 140) which is about the same as that.
0) (the quenching hardness of S55C is more than Hv 800). Further, in this experiment, the thickness at which Hv of 1000 or more is obtained is about 60 μm, which is large.

[0034]

Example 2 A powder electrode was used in which the base material was steel (special tool steel), TiB _{2 was} used as fine ceramics, and Fe powder was used as an auxiliary agent. First, as shown in FIG. 12, they were laminated by discharge deposition using a powder electrode. After stacking, pulse electric processing was performed. At that time, the stacking and the pulse electric discharge machining were performed for each layer, and the pulse electric machining was performed after all the stacking was completed.

As a result, a graded material having a coating layer in which the TiB ₂ content gradually decreased from the surface was obtained. Further, the former was more laborious, but the adhesive force was stronger. The Vickers hardness of the surface is Hv = 2000-
2500, Vickers hardness near the base metal is Hv = 5
It was 50-600.

[0036]

Example 3 A powdery electrode was used in which a base material was steel (special tool steel) and a diamond powder and a cobalt powder were mixed as a hard material. First, as shown in FIG. 13, they were laminated by discharge deposition using a powder electrode. After stacking, pulse electric discharge machining was performed. At that time, the stacking and the pulse electric discharge machining were performed for each layer, and the pulse electric machining was performed after all the stacking was completed.

As a result, a graded material having a coating layer in which the diamond content gradually decreased from the surface was obtained. The Vickers hardness of the surface portion (where many diamonds are) was Hv = 3500-4000, and the Vickers hardness of the portion near the base material was Hv = 550-600.

[0038]

Example 4 By performing the processing shown in FIG. 1, a fine coating layer was formed on the inner surface of the mold with fine ceramics or WC-Co. First, as shown in FIG. 1, the electrode was subjected to three-dimensional shape processing by using a material such as copper or graphite which is usually used for low consumption electric discharge machining. afterwards,
The inner surface of the workpiece was sprayed by mixing TiB ₂ powder with about 20% cobalt powder. Its thickness is about 100 μm. The sprayed film is slightly irregularly deposited as shown in FIG.

Then, again, using the electrode shown in FIG. 1 (the one used previously, the one having the modified shape size, or the one having a slightly smaller size), the electric discharge machine is used to perform the pulse electric discharge machining process. went. This processing condition is Ip = 3
A, τp = 64 μs, τr = 256 μs, discharge voltage = 100
It is around V. As shown in FIG. 15, the cavity on which the surface of the workpiece was covered with high shape accuracy was obtained. According to this processing, a die casting mold for high temperature pouring can be manufactured.

Here, in the case of performing pulse electric discharge finishing using a slightly smaller electrode, oscillating machining which is well known in electrical discharge machining (the electrode is eccentrically moved in the horizontal direction and the eccentric dimension is larger than the electrode dimension). However, the finished surface roughness of the side surface and the bottom surface is factory-set).

In this method of this embodiment, the shape of the cavity, which is difficult to process by a normal processing method, is subjected to electric discharge machining, a material such as fine ceramics is deposited on the inner surface by thermal spraying, and pulse electric discharge machining is performed thereon. It is re-melted by. It is impossible or difficult to melt by other laser or high frequency heating, which is an extremely great advantage of the present invention.

In the above embodiment, the discharge deposition or the thermal spraying method was used as the coating means for the coating material, but other means such as the electrodeposition method and the low temperature vapor deposition method can also be used, and various coating means can be used in combination. It goes without saying that you can do it.

[0043]

As described in detail above, according to the present invention,
It is possible to easily form a dense and strong coating layer that does not have defects such as dimensional change of the base material, decrease in hardness (strength), peeling of the film, etc., and has desired surface characteristics such as corrosion resistance and heat resistance with a sufficient thickness. it can. For example, high temperature gas or steam projection of high temperature turbine blades, die cavity part for casting high temperature molten metal, shot blast nozzle part of molten metal forging die and other parts (for example injection molding machine pipe part) ,
It can also be used for coating fine ceramics only on the cutting edge of a steel mold.

Further, a functionally graded material having a so-called functionally graded film whose composition gradually changes up to the surface of the base material can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a procedure of discharge deposition by a powder compact electrode.

FIG. 2 Al obtained by discharge deposition in Example 1
It is a figure which shows the analysis result by EPMA of a coating layer.

FIG. 3 Al obtained by discharge deposition in Example 1
It is a figure which shows the analysis result by the X-ray diffraction of a coating layer.

FIG. 4 WC obtained by discharge deposition in Example 1.
It is a figure which shows the X-ray-diffraction result of a -Fe coating layer.

FIG. 5 is a diagram illustrating a circuit configuration of pulse electric discharge machining.

FIG. 6 is a diagram showing a pulse waveform of pulse electric discharge machining.

FIG. 7 is a diagram showing an X-ray diffraction result of a WC-Fe coating layer obtained by performing pulse electric discharge machining (finishing) on the WC-Fe coating layer in Example 1.

8 is a sample obtained by discharge deposition in Example 1. FIG.
It is a cross-sectional micrograph of (metal structure).

FIG. 9: WC obtained by discharge deposition in Example 1
4 is a micrograph of a cross section (metal structure) of a sample obtained by performing pulse electric discharge machining (finishing) on the Fe coating layer.

FIG. 10: W obtained by discharge deposition in Example 1
It is an SEM photograph of the cross section (metal structure) of the sample obtained by performing pulse electric discharge machining (finishing) on the C-Fe coating layer.

FIG. 11: W obtained by discharge deposition in Example 1
It is a figure which shows the distribution of the Vickers hardness (Hv) from the surface of the sample cross section obtained by performing pulse electric discharge machining (finishing) on the C-Fe coating layer.

FIG. 12 is a diagram illustrating a procedure for laminating a coating material in Example 2.

FIG. 13 is a diagram illustrating a stacking procedure of coating materials in Example 3.

FIG. 14 is a diagram showing a cavity shape obtained by electrical discharge machining and thermal spraying in Example 4.

FIG. 15 is a diagram showing a cavity shape after pulse electric discharge machining in Example 4.

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[Procedure amendment]

[Submission date] February 15, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

In the above-mentioned embodiment, the discharge deposition or the thermal spraying method was used as the covering means for the covering material, but other means such as an electrodeposition method, a low temperature vapor deposition method, etc. can also be used, and various covering means can be used in combination. It goes without saying that you can do it. Well
In addition, electrical discharge precipitation machining (primary machining) and electrical discharge remelting machining (secondary machining)
Process) under the same or different conditions multiple times.
Needless to say, it is possible to
Show.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

[0043]

[Embodiment 5] In this embodiment, electrical discharge precipitation machining (primary machining) and electrical discharge re-machining are performed.
Once to perform each melt processing (secondary processing) once
It is an example of repeating the above process a plurality of times. Release
After the base material coating by electrodeposition processing (primary processing), pulse discharge
Only once melt processing (secondary processing) is performed
The surface layer was blown away and the base metal surface was exposed.
Or when a thick surface treatment layer cannot be formed.
It is effective when applied in combination.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

First, the first pulse discharge deposition machining (1
The processing conditions for the following processing are: electrode material: powder electrode (in Example 1
The same as the used WC-Fe electrode), electrode polarity: minus, I
p: 25 A, τp: 8 μsec, τr: 512 μsec, during processing
Time: 5 minutes condition, second pulse discharge remelting processing
The processing conditions for (secondary processing) are: electrode material: copper plate, electrode electrode
Gender: Minus, Ip: 15A, τp: 1024μs, τr:
The conditions were 1024 μs and processing time: 7 minutes. Other conditions
Is the same as in the first embodiment. Then, the same requirements as in the first embodiment
Deposited layer of WC-Fe on the surface of the base material by discharge precipitation
After forming the, repeat the process of performing secondary processing 5 times
did. Figure 16 shows a cross-sectional photograph of the sample taken with an optical microscope.
17 shows the analysis result by X-ray diffraction. Thickness from Figure 16
A uniformly spread deposition layer of about 50 μm was confirmed. Also
From FIG. 17, the existence of WC was confirmed. Hardness of sample cross section
It was about Hv1650 on average,
It was confirmed that the hardness was high. Note that FIG. 18 shows the base metal
Coating and pulse melting remelting processing under the secondary processing conditions
Of the sample when performing each step once
It is a cross-sectional photograph showing the surface treatment layer is discontinuous and uneven.
The state is shown. FIG. 19 shows X-ray diffraction after primary processing
It is an analysis result.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Added

[Correction content]

[0045]

As described in detail above, according to the present invention, there is no defect such as dimensional change of the base material, decrease in hardness (strength), film peeling, etc., and it is desired to have corrosion resistance, heat resistance, etc. with sufficient thickness. It is possible to easily form a dense and hard coating layer having the above surface characteristics. For example, high temperature gas or steam projection of high temperature turbine blades, die cavity part for casting high temperature molten metal, shot blast nozzle part of molten metal forging die and other parts (such as injection molding machine pipe part), It can also be used for coating fine ceramics only on the cutting edge of a steel mold.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Added

[Correction content]

Further, a functionally gradient material having a so-called functionally gradient film whose composition gradually changes up to the surface on the base material can be manufactured at low cost.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] Fig. 16

[Correction method] Added

[Correction content]

FIG. 16 is a micrograph (× 160) of a cross section of a sample (metal structure) obtained by repeating discharge deposition (primary processing) and pulse discharge remelting processing (secondary processing) five times in Example 5. ..

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 17

[Correction method] Added

[Correction content]

FIG. 17 is a diagram showing an X-ray diffraction result of a WC-Fe coating layer of a sample obtained by repeating the steps of primary processing and secondary processing in Example 5.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 18

[Correction method] Added

[Correction content]

FIG. 18 is a micrograph (× 160) of a cross section of a sample (metal structure) obtained by performing each of the steps of primary processing and secondary processing once in Example 5.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 19

[Correction method] Added

[Correction content]

FIG. 19 is a diagram showing the X-ray diffraction result of the sample after the primary processing in Example 5.

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 16

[Correction method] Added

[Correction content]

FIG. 16

[Procedure Amendment 11]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 17

[Correction method] Added

[Correction content]

FIG. 17

[Procedure Amendment 12]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 18

[Correction method] Added

[Correction content]

FIG. 18

[Procedure Amendment 13]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 19

[Correction method] Added

[Correction content]

FIG. 19

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Claims (5)

[Claims] 1. A surface of a base material made of a metal material is coated with a metal or a non-metal material, and then the deposit is remelted in every minute region by pulse electric discharge machining in a liquid, a gas or a vacuum, A surface treatment method for a metal material, which comprises diffusing and mixing a base material and the coating material to form a dense coating layer on the surface of the base material. 2. The method according to claim 1, wherein the coating material comprises one kind or two or more kinds of metal or alloy, non-metal element, ceramics, carbide, nitride and boride. 3. The method according to claim 1, wherein the coating means for coating the coating material is any one of a thermal spraying method, an electrodeposition method, a low temperature vapor deposition method, and a discharge deposition method using an electrode that easily wears. 4. The method according to claim 1, wherein the pulsed electric discharge machining is performed by using an electrode that is hard to wear as a negative electrode. 5. Coating of coating material and pulse electric discharge machining
The method according to claim 1, wherein the method is performed layer by layer so that the coating layer has a gradient.