JP2007100129A - Surface coating method and surface coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coating method by which a dense surface coating film having a sufficient thickness can be formed on the surface of a base material to be coated by using a coating material different from the base material, and the surface coating material. <P>SOLUTION: The surface coating method has a process comprising allowing a powder 2 of the coating material to exist on the surface of a base material 1 to be coated, then rotating a pressure-contact body 4 while pressing the tip contact part 5 of the pressure-contact body 4 onto the powder 2 toward the surface of the base material 1 to be coated with a set load, at the same time, heating at least an area applied with the load of the surface of the base material 1 and the powder 2 of the coating material to a prescribed temperature or higher, and forming an initial coating film 3 on the surface of the base material 1 by moving the pressure-contact body 4 along the surface of the base material 1, and a heating and diffusing process for finishing a surface coating film 30 by diffusing the components of the coating material into the base material 1 from the initial coating film 3 through the coating interface by heating the base material 1 or the like in a non-oxidizing atmosphere. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface coating method and a surface coating film in which a surface coating film is formed on a surface of a base material to be coated using a coating material separate from the base material.

Conventionally, CVD (Chemical Vapor) is the surface coating method of this kind.
Deposition method and thermal spraying method. The former is a technique for forming a thin film thickness on the order of several micrometers, and is used for forming wiring materials and the like. The CVD method has the advantage of being able to form a highly dense film, but only forms a very thin film as described above, and cannot be used to form a thick film.
The latter thermal spraying method is a technique for forming a thick film having a thickness of several hundred micrometers. However, the film quality is porous, and it cannot be used to form a film that requires denseness that can completely block outside air such as gas intrusion.

  In addition, by using a friction stir technology, a rotating tool harder than the base material is pushed into and moved on the surface of the metal workpiece, and the modified layer of the base material itself by the friction stir processing is then moved to the surface. There is a surface treatment method for forming (Patent Document 1, Patent Document 2). Although this surface treatment technology can efficiently modify the surface of the metal workpiece, the surface treatment using the metal workpiece itself, that is, only the base material, is different from the base material. Conventionally, the surface coating using has not been considered at all.

JP 2001-347360 A JP 2003-164978 A

  The present invention has been made in view of the above background of the prior art, and a surface coating film having a dense and sufficient film thickness is formed on the surface of a base material to be coated using a coating material separate from the base material. It is an object to provide a surface coating method and a surface coating film that can be formed.

  In order to achieve the above object, the surface coating method according to the first aspect of the present invention is such that the powder of the coating material is present on the surface of the base material to be coated, and the tip contact portion is placed on the pressure contact body from above the powder. Rotating while pressing with a set load toward the surface of the base material to be coated, and at this time, the surface of the base material to be coated and the powder of the covering material at least in a region where the load acts are heated to a predetermined temperature or higher Forming the initial coating film on the surface of the base material to be coated by moving the pressure contact body along the surface of the base material to be coated, and heating the initial coating film in a non-oxidizing atmosphere. And a heating diffusion step of diffusing the coating material component from the coating interface toward the base material to finish the surface coating film.

  First, the initial coating film is formed by increasing the temperature of the powder of the coating material and the surface of the base material to the predetermined temperature or more and generating frictional heat by moving the pressure contact body while applying the set load. Thus, the powder of the coating material is once semi-molten in the region where the load acts, and is adhered to the base material. Therefore, the predetermined temperature and the set load are relatively determined so that at least the powder of the covering material is in the semi-molten state. That is, if the predetermined temperature is raised, the set load can be reduced accordingly, and if the predetermined temperature is lowered, the set load is increased accordingly. The film thickness of the initial coating film can be increased or decreased by selecting the predetermined temperature and set load at which the semi-molten state is easily achieved, including the particle size of the powder of the coating material.

  Further, in the heating diffusion step, the surface coating film is finished by heating in a non-oxidizing atmosphere and diffusing the coating material component from the initial coating film toward the base material from the coating interface. The processing distortion at the time of initial coating film formation is removed, and homogeneity is ensured, and a gradient composition based on the diffusion is formed between the film and the base material. Therefore, the characteristics such as adhesion can be improved.

  That is, according to the first aspect of the present invention, the powder of the coating material separate from the base material is used, and the initial coating film using the powder as a material is coated by raising the temperature above a predetermined temperature and applying a set load. Since it adheres to the surface of the target base material and is subsequently heated in a non-oxidizing atmosphere, the coating material components are diffused from the initial coating film toward the base material through its coating interface to finish the surface coating film. A dense surface coating film having a sufficient film thickness can be formed on the surface of the base material to be coated using a coating material separate from the base material.

  The surface coating method according to a second aspect of the present invention is characterized in that, in the first aspect, the powder of the covering material is aluminum or aluminum alloy powder. In the present invention, by using aluminum or an aluminum alloy as a covering material, the above-described effects obtained are remarkable.

  The surface coating method according to a third aspect of the present invention is characterized in that, in the first aspect, the powder of the coating material is a powder of a mixture of different materials. Thus, by using a powder of a mixture of different materials as the powder of the coating material, the different materials can be appropriately combined to form a surface coating film having desired characteristics. Examples thereof include a composite system of aluminum (Al) powder and silicon (Si) powder, a composite system of aluminum (Al) powder and boron nitride (BN) powder, and the like.

  In the surface coating method according to the fourth aspect of the present invention, in any one of the first to third aspects, the tip contact portion of the pressure contact body is formed in a conical shape, and the pressure contact body is a base material to be coated. The inclination angle and the conical shape are pressed against the surface of the coating material by rotating the powder of the coating material existing on the surface of the base material to be coated with the tip contact portion of the rotating press contact body. It is comprised so that it may wind between between the surfaces of the base material to be covered.

  According to the present invention, the powder of the coating material existing on the surface of the base material to be coated is stably and reliably wound between the tip contact portion of the rotating press contact body and the surface of the base material to be coated. Therefore, the surface coating film can be formed efficiently.

The surface coating method according to the fifth aspect of the present invention is characterized in that, in the fourth aspect, the predetermined temperature related to the temperature increase is 200 ° C. or higher.
By raising the temperature of the region where the load acts to 200 ° C. or higher, the set load required to realize the semi-molten state can be small, so that the existing load is sufficient. The semi-molten state can be easily realized using an industrial device, and an increase in cost can be prevented.

  A surface coating method according to a sixth aspect of the present invention includes, in any one of the first to fifth aspects, a nitriding treatment step of forming a nitride film by nitriding treatment following the heating diffusion step. It is characterized by. According to the present invention, a dense nitride film having a sufficient film thickness can be formed on the surface of a base material to be coated using a coating material separate from the base material.

  The surface coating method according to a seventh aspect of the present invention includes, in any one of the first to fifth aspects, an oxidation treatment step of forming an oxide film by oxidation treatment following the heat diffusion step. It is characterized by. According to the present invention, a dense oxide film having a sufficient film thickness can be formed on the surface of a base material to be coated using a coating material separate from the base material.

  An eighth aspect of the present invention is a surface coating film formed by the method according to any one of the first to seventh aspects. According to the present invention, the effects of the first to seventh aspects can be similarly obtained.

  According to the present invention, a dense surface coating film having a sufficient film thickness can be formed on the surface of a base material to be coated using a coating material separate from the base material.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of an essential part for explaining one embodiment of a surface coating method according to the present invention, FIG. 2 is a side view of a pressure contact body used for carrying out the surface coating method, and FIG. It is the figure which copied the electron micrograph of the cross section with the base material to be coated about the surface coating film formed by the method, and (B) is an enlarged view of (A).

  The surface coating method according to the present embodiment includes a step of forming an initial coating film 3 (FIG. 1) on the surface of the base material 1 to be coated using powder 2 of a coating material separate from the base material 1. A heating diffusion step of heating in a non-oxidizing atmosphere to diffuse the coating material component from the initial coating film 3 toward the base material 1 from the coating interface to finish the surface coating film 30 (FIG. 3). Have.

  The initial coating film 3 is formed in such a manner that the powder 2 of the coating material is present on the surface of the base material 1 to be coated, and the tip contact portion 5 of the pressure contact body 4 is placed on the powder 2 from above the powder 2. The surface of the base material 1 to be coated and the powder 2 of the coating material at least in a region where the load is applied are heated to a predetermined temperature or more in this state. By moving the pressure contact body 4 along the surface of the base material 1 to be coated, the powder 2 of the covering material is semi-molten by the frictional heat generated by rotating the pressing material 2 while raising the temperature to the predetermined temperature or more and pressing it with the set load. It is formed by becoming a state and adhering to the surface of the base material to be coated.

  Here, examples of the base material 1 to be covered include stainless steel and steel. Of course, it is not limited to these materials. What is necessary is just to be able to apply this invention in combination with a coating | covering material.

In the present invention, the coating material (powder 2) is a separate material from the base material 1 to be coated, and the present invention is different from a surface treatment that simply modifies the surface of the base material 1 itself. . The covering material is not limited to a specific material, but the material of the covering material is determined by the combination of the purpose of the covering and the base material 1 to be coated. For example, a coating material made of aluminum or an aluminum alloy is a good combination in terms of workability and film characteristics (denseness) for a stainless steel material. Instead of aluminum, copper, lanthanum and the like can be exemplified as the covering material.
Further, since the present invention uses the powder 2 of the coating material, different materials such as a composite system of aluminum (Al) powder and silicon (Si) powder, a composite system of aluminum (Al) powder and boron nitride (BN) powder, etc. Thus, it is possible to easily form the various surface coating films 30 having desired characteristics by appropriately combining the different materials.

  The particle size of the powder 2 of the coating material depends on the kind of the material, the combination with the base material 1 to be coated, and the difference in “predetermined temperature” and “set load” described later when the initial coating film 3 is formed. Although it varies, it is usually easy to handle when the particle size is 3 to 40 micrometers, preferably 5 to 20 micrometers.

  In the present embodiment, the structure of the pressure contact body 4 is a cylindrical body as shown in FIG. 2, and the tip contact portion 5 is formed in a conical shape. The cylindrical body has a diameter a of 20 mm and a conical height b of 0.5 mm. With the conical shape (diameter a: 20 mm, height b: 0.5 mm), the coating material powder 2 existing on the surface of the coating target base material 1 is rotated with the tip contact portion 5 of the rotating press contact body 4. It winds between the surface of the base material 1 to be covered. When such a pressure contact body 4 is used, it is desirable to use a cylindrical cover 6 that prevents the powder 2 from scattering as shown in FIG. The conical shape (diameter 20 mm, height 0.5 mm) is an example, and it is needless to say that the invention is not limited to these.

The set load of the press contact body 4 is the magnitude of the force with which the press contact body 4 is pressed against the surface of the base material 1 to be coated, and friction heat is generated by rotating the press contact body 4 while pressing the press contact body 4. It is set to a size that allows the powder 2 in the region where the material acts to be in a semi-molten state. Furthermore, at that time, at least the surface of the base material 1 to be coated and the powder 2 of the covering material in the region where the frictional heat is generated due to the action of the load are heated to a predetermined temperature or higher by the heating means, The required setting load changes. That is, if the “predetermined temperature” is increased, the set load may be small, and in the opposite case, it needs to be increased.
Here, if the region where the load is applied is heated to 200 ° C. or more, the set load required to realize the semi-molten state can be small, and the existing load is sufficient. Thus, the semi-molten state can be easily realized by using the load device, and an increase in cost can be prevented.

  Then, the press contact body 4 is rotated while being pressed with the set load as described above, and is moved along the surface of the base material 1 to be covered, whereby the initial coating film 3 is formed on the surface of the base material 1 to be covered. . The initial coating film 3 is formed on the surface of the base material as shown in FIGS. 3A and 3B because the powder 2 of the coating material adheres to the base material surface under the set load through a semi-molten state. These irregular irregular shapes can be followed or absorbed to adhere without voids. Furthermore, although the film thickness also depends on the particle diameter of the powder 2 to be used, it can be formed as thick as several tens of micrometers to several hundreds of micrometers.

  The heat diffusion step is to diffuse the coating material component from the initial coating film 3 toward the base material 1 from the coating interface to finish the surface coating film 30, such as an inert gas atmosphere or a reduced pressure atmosphere. Known methods including a non-oxidizing atmosphere can be applied. By this heat diffusion, the surface coating film 30 is free of processing distortions and the like during the formation of the initial coating film 3 to ensure a uniform and denseness, and is based on the diffusion between the surface coating film 30 and the base material 1. A gradient composition is formed, and this gradient composition improves the continuity between the film 30 and the base material 1, thereby improving the coating properties such as adhesion.

[Example 1]
<Formation of surface coating film>
As the powder 2 of the coating material, an aluminum powder having a particle diameter of 5 to 20 micrometers produced by a gas atomization method was used. Note that the method for producing the powder is not limited to this. As the base material 1 to be coated, a plate-shaped stainless steel material (SUS430) was used, and the same stainless steel material (SUS430) as the base material 1 to be coated was also used as the pressure contact body 4. As shown in FIG. 2, the pressure contact body 4 includes a cylindrical body having a diameter of 20 mm and a tip contact portion 5, and the tip contact portion 5 is formed in a conical shape (diameter 20 mm, height 0.5 mm). ing.

First, the base material 1 made of stainless steel (hereinafter sometimes referred to as “stainless steel base material 1”), the powder 2 of the aluminum coating material, and the tip contact portion 5 of the stainless steel pressure contact body 4 are heated by a gas burner. Their temperature was raised to 200 ° C. The temperature is sufficiently increased, and the pressure contact body 4 is vertically pressed toward the surface of the base material 1 to be coated with a set load of 10 kg / cm ² , and the linear velocity of the outer periphery of the tip contact portion 5 is 6 m / second. Rotate at rotation speed. In this state, the pressure contact body 4 is moved along the surface of the base material while being pressed against the stainless base material 1 at a speed of 1 mm / second. Thereby, the initial coating film 3 made of an aluminum coating material is formed on the surface of the stainless steel base material 1.

  In the center portion of the tip contact portion 5 of the press contact body 4, the linear speed of the rotational speed is smaller than 6 m / second, and the powder 2 is less likely to be a semi-molten body and a film is not easily formed. There is a little. Therefore, it is preferable to move so that the portion of the tip contact portion 5 of the press contact body 4 that has a high linear velocity near the periphery passes through the entire surface of the base material 1 to be coated, and thus the entire surface is uniform. An initial coating film 3 can be formed.

When the predetermined temperature heated by the gas burner is 200 ° C., when the linear velocity is changed with the others set as described above, almost no film is formed at 0.5 m / second, and 1 m / second. The film thickness was about 1 to 5 micrometers, the film thickness was about 5 to 20 micrometers at 3 m / second, and a film thickness of 40 micrometers or more was obtained at 6 m / second or more. Similarly, when the predetermined temperature heated by the gas burner is 200 ° C. and the other is set as described above and the set load is changed, no film is formed at 0.1 kg / cm ² , and 1 kg / little film even cm ^2, thickness of 40 micrometers or greater in the 5 kg / cm ² or more was obtained. That is, it can be said that it is possible to efficiently form a film by appropriately setting the film forming conditions according to the purpose.
It is also possible to form the initial coating film 3 by keeping the predetermined temperature at room temperature, that is, without heating with a gas burner or the like, and only increasing the installation load of the pressure contact body 4.

  After the initial coating film 3 is formed, a heat diffusion treatment is performed in a vacuum atmosphere at 700 ° C. for 2 hours to diffuse the aluminum component from the initial coating film 3 to the stainless steel base material 1 side, thereby the surface coating film 30. Finished.

<Analysis of surface coating film>
The sample on which the surface coating film 30 was formed was subjected to analysis of the sample cross section using an electron beam probe microanalyzer 8800/8900 (manufactured by JEOL Ltd.). As a result, it was confirmed from electron microscope observation that a dense surface coating film 30 of aluminum was formed on the surface of the stainless steel base material 1 as shown in FIGS. FIG. 3B is an enlarged view of the region indicated by reference numeral 7 in FIG. 3A, and the surface coating film 30 of aluminum is in a dense state following the surface irregularities of the stainless steel base material 1. It can be confirmed that the material adheres to the stainless steel base material 1. In FIG. 3A, reference numeral 9 indicates a resin layer, and the resin layer 9 is attached to the sample surface for the above analysis.

  The result of composition analysis by mapping is shown in FIG. 4 and FIG. 5 which is an enlarged view thereof. A region dotted with dots indicates a region where the analysis target component is included, and the degree of the dots (light and shade) corresponds to the amount of component existence. (A) shows that the surface coating film 30 is aluminum, and aluminum does not exist in other regions. (B) shows that chromium (Cr) is present in the stainless steel base material 1 and in other regions. Indicates that it does not exist (which is natural), and (C) indicates that iron (Fe) is present in the stainless steel base material 1 and is not present in other regions (which is natural). . In this example, as shown in FIG. 4A, it was confirmed that the film thickness of the surface coating film 3 was about 70 to 80 micrometers.

  Further, as shown in an enlarged view in FIG. 5, it was confirmed that the aluminum component was diffused from the initial coating film 3 to the stainless steel base material 1 side by the heat diffusion treatment. That is, by this heat diffusion, the surface coating film 30 is free of processing distortion and the like during the formation of the initial coating film 3 to ensure uniform and denseness, and at the interface with the stainless steel base material 1. A graded composition based on diffusion is formed, and this graded composition improves the continuity between the film 30 and the base material 1, and thus seems to improve the coating properties such as adhesion.

[Example 2 and Example 3]
<Formation of composite surface coating film>
Surface coating film 30 was formed using a mixture of aluminum and silicon (Example 2) and a mixture of aluminum and boron nitride (Example 3) as powders of the coating material. The mixing ratio of the two was Al: Si = 2: 8 and Al: BN = 8: 2 by weight.

  The structure of the pressure contact body 4 used in Examples 2 and 3 is a cylindrical body having a diameter of 20 mm and a conical height of 0.5 mm as shown in FIGS. 6 and 7. The body 4 is pressed toward the surface of the base material 1 to be coated with an inclination θ of 1.5 degrees with respect to the normal 10 of the surface. Due to this inclination angle (1.5 degrees) and the conical shape (diameter 20 mm, height 0.5 mm), the powder 2 of the coating material existing on the surface of the base material 1 to be coated It is wound between the tip contact portion 5 and the surface of the base material 1 to be covered.

  The tilt angle (1.5 degrees) and the conical shape (diameter 20 mm, height 0.5 mm) are examples, and of course are not limited to these. The set load was 550 kg to 1500 kg as the total pressure of the press contact body 4. In addition, it heated at room temperature, without heating by a gas burner etc. Other conditions are the same as in the first embodiment.

<Analysis of surface coating film>
In both Example 2 and Example 3, the sample on which the surface coating film 30 was formed was analyzed for the sample cross section using an electron beam probe microanalyzer 8800/8900. As a result, it was confirmed by electron microscope observation that a dense surface coating film 30 having a film thickness of about 60 to 70 micrometers was formed on the surface of the stainless steel base material 1 as in Example 1. The presence of boron (B) and nitrogen (N) was confirmed by quantitative analysis of the surface coating film 30 portion. Other components were confirmed in the same manner as in Example 1. Tables 1 and 2 show the results of the quantitative analysis.

[Example 4]
<Nitride film formation>
The sample having the aluminum surface coating film 30 produced in Example 1 was subjected to nitriding treatment at 570 ° C. for 2 hours using a plasma nitriding apparatus (manufactured by JEOL Ltd.), and the aluminum surface coating film was converted into an aluminum nitride film. Changed to. When the hardness was measured with a micro Bickus hardness tester (manufactured by Akashi Seisakusho Co., Ltd.), it was confirmed that an altitude of about 1100-1300 was exhibited.

[Example 5]
<Oxide film formation>
The sample having the aluminum surface coating film 30 produced in Example 1 was subjected to an oxidation treatment at 700 ° C. for 5 hours using a known oxygen atmosphere path, and the aluminum surface coating film was changed to an aluminum oxide film. When the hardness was measured with a micro Biccus hardness meter (manufactured by Akashi Seisakusho Co., Ltd.), it was confirmed that an altitude of about 600 to 800 was exhibited.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a surface coating method and a surface coating film that form a surface coating film on the surface of a base material to be coated using a coating material that is separate from the base material.

It is a principal part perspective view for demonstrating one Embodiment of the surface coating method which concerns on this invention. It is a side view of the press-contacting body used for implementation of the surface coating method. It is the figure which copied the electron micrograph of the cross section with the base material to be coated about the surface coating film formed by the same method, and (B) is an enlarged view of (A). (A) (B) (C) is a figure which shows the result of the composition analysis by mapping. (A) (B) (C) is a figure which shows the result of the composition analysis by mapping, and is a partially expanded view of FIG. It is a principal part side view for demonstrating other embodiment of the surface coating method which concerns on this invention. It is a side view of the press-contacting body used for implementation of the surface coating method.

Explanation of symbols

1 Base material to be covered (stainless steel base material)
2 Coating material powder 3 Initial coating film 4 Pressure contact body 5 Tip contact portion 30 Surface coating film

Claims (8)

The coating material powder is present on the surface of the base material to be coated, and the pressure contact body is rotated from above the powder while pressing the tip contact portion against the surface of the base material to be coated with a set load, and at least The surface of the base material to be coated in the region where the load acts and the powder of the covering material are heated to a predetermined temperature or more, and the pressure contact body is moved along the surface of the base material to be coated. Forming an initial coating film on the surface of the target base material;
A surface coating method comprising: a heating diffusion step of heating in a non-oxidizing atmosphere and diffusing a coating material component from the initial coating film into a base material from the coating interface to finish the surface coating film.   2. The surface coating method according to claim 1, wherein the coating material powder is aluminum or aluminum alloy powder.   2. The surface coating method according to claim 1, wherein the powder of the covering material is a powder of a mixture of different materials.   In any one of Claim 1 to 3, the front-end | tip contact part of a press-contact body is formed in cone shape, this press-contact body is pressed with the predetermined | prescribed inclination with respect to the surface of a base material to be coated, The conical relationship is configured such that the powder of the covering material existing on the surface of the base material to be covered is wound between the tip contact portion of the rotating press contact body and the surface of the base material to be covered. A surface coating method characterized by comprising:   The surface coating method according to claim 4, wherein the predetermined temperature for the temperature rise is 200 ° C. or higher.   6. The surface coating method according to claim 1, further comprising a nitriding treatment step of forming a nitride film by nitriding treatment following the heating diffusion step.   6. The surface coating method according to claim 1, further comprising an oxidation treatment step of forming an oxide film by an oxidation treatment subsequent to the heat diffusion step.   A surface coating film formed by the method according to claim 1.

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