JP2003129111A - Porous sintered compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous sintered compact to be easily cleaned, which is a sintered compact of a porous metal or ceramic, comprising a porous body provided with many micropores, and has a ground surface from which the ground chips are easily removed. SOLUTION: The porous sintered compact comprises a finely porous layer having mutually communicating holes of small diameters, which open to the surface, and a coarsely porous layer having mutually communicating holes of large diameters, which is joined to the finely porous layer, and comprises a cobalt-based or nickel-based hard metal. The method for manufacturing the sintered compact comprises filling a forming die with a fine grain powder and a coarse grain powder, compacting them so that the fine grain powder layer and the course grain powder layer come into contact with each other, then firing the above compact to make the porous sintered compact in which the finely porous layer of the fine grain powder layer and a coarsely porous layer of the coarse grain powder layer are joined in the sintered compact, forming the surface by grinding the finly porous layer, and cleaning the sintered compact layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous sintered body having two or more porous regions having different pore sizes of the sintered body and a method for producing the same.

[0002]

2. Description of the Related Art Porous sintered bodies made of metals or alloys are used, for example, as oil-impregnated bearings impregnated with lubricating oil and filters for filtering gas or liquid. The porous sintered body may be used as it is sintered, but in many cases, it is subjected to grinding, polishing, and other finishing processes.
The surface is often ground or polished (hereinafter, simply referred to as grinding including polishing and surface finishing) to form a desired shape.

A porous sintered body is sintered from a fine powder of a sintering raw material (for example, alloy fine powder) and has a large number of communicating fine pores. When the surface of this sintered body is ground, The fine particles of the alloy that have become shavings often enter the pores or pores of the sintered body and are clogged, and depending on the application, the clogging of pores may significantly deteriorate the product characteristics.
Therefore, after grinding, the sintered body is cleaned to remove the clogging of pores. Furthermore, even during use, for example, the filter is likely to be clogged, and the clogging increases the flow resistance or pressure loss of the fluid passing through the filter, which is not preferable.

[0004]

Conventionally, as a method for removing grinding debris, ultrasonic cleaning is performed, or high-pressure water or air is made to flow from the surface opposite to the grinding surface to push away the debris particles. It has been implemented. It was not easy to remove the grinding dust particles when they entered the fine pores of the sintered body having an opening size of 50 μm or less.

In view of the above problems, the present invention is a porous calcination that can easily remove by grinding the grinding dust particles that have entered from the ground surface when the surface of a sintered body having fine pores is ground. It is an attempt to provide a union. The present invention further seeks to provide a method for producing a porous sintered body which is easy to wash for removing grinding debris from such a ground surface.

[0006]

The porous sintered body of the present invention comprises two or more porous regions having different pore sizes in communication with each other. The porous sintered body is preferably
The two or more porous regions are composed of a fine pore layer having a small communication hole size and a coarse pore layer having a large communication hole size.
Then, it has a ground surface of the pore layer, and the ground surface is utilized so as to perform a required function.

That is, the porous sintered body of the present invention is a sintered body composed of a porous sintered layer, and the sintered layer has a small-diameter communicating hole that opens and communicates with the surface of the sintered body. It is characterized in that it comprises a pore layer and a coarse pore layer having a large-diameter communicating hole that is connected to the pore layer and communicates with each other.

In the pore layer, the thickness of the pore layer can usually be made relatively thin if the function of the pores in its functional aspect can be fulfilled. Therefore, coarse pores are formed on the back surface side of the pore layer. By forming the coarse pore layer having the pores, the pore layer can be reinforced, and the required size and strength of the sintered body can be maintained depending on the intended use of the sintered body.

In such a porous sintered body having a multi-layered structure, even if grinding dust particles enter deep into the pores from the grinding surface during grinding, the grinding dust particles can easily pass through the coarse pores to the coarse pore layer side during cleaning. It can be extruded and washed, and scrap particles that have entered shallowly from the grinding surface can be easily supplied from the thin pore layer by supplying pressure medium to the pore layer from the surface opposite to the grinding surface through the coarse pore layer. Can be extruded. In this way, a porous sintered body that can be easily washed can be provided.

In the method for producing a porous sintered body of the present invention, a fine grain powder and a coarse grain powder are filled in a molding die, and the fine grain powder layer and the coarse grain powder layer are brought into contact with each other in the molding die. To form a porous body in which a fine-pore layer sintered from a fine-grain powder layer and a coarse-pore layer sintered from a coarse-grain powder layer are bonded in the sintered body. It forms a sintered body. Preferably, the molded body is sintered together with the molding die at a sintering temperature without being released from the molding die to sinter into a porous sintered body.

Further, in another production method, a fine-grained powder layer made of fine-grained powder is pressure-molded, and a coarse-grained powder layer made of coarse-grained powder is pressure-molded to obtain the fine-grained powder layer. And a coarse particle powder layer are joined, fired, and integrally sintered to produce a porous sintered body.

According to the present invention, at the time of pressure molding, a fine-grained powder layer and a coarse-grained powder layer are stacked in a molding die so as to be pressure-molded, and then the mold is released. A manufacturing method in which the pressure-formed body is fired and sintered is also included.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the porous sintered body of the present invention, the shape and the size of the sintered body itself depend on the application, but the surface layer is composed of a pore layer required for the application, and A coarse hole layer is integrally formed on the.

The pore diameter of the fine pore layer is usually largely determined by the use of the porous sintered body, but the pore diameter of the fine pore layer of the sintered body is, for example, in the range of 10 to 40 μm on average. On the other hand, the average pore diameter of the coarse pore layer is 40 to 200 μm.
Range is used. The pore diameter range of the pore layer is usually relatively difficult to remove the clogging of grinding dust by washing, whereas the sintered body of the present invention has a coarse particle size range of the above average particle size range. By providing the pore layer, it is possible to form the pore layer thinly and facilitate removal of grinding dust in the pore layer.

Therefore, the thickness of the pore layer is necessary for achieving the function in the application of the porous sintered body and is preferably as thin as possible, but the thickness thereof is, for example, 0.5 to 5 mm.
The range of 1.0 to 2.0 mm is preferably adopted. The overall strength of the sintered body can be determined by the strength of the rough hole layer behind it.

The porous sintered body of the present invention can be formed of a metal, particularly an alloy, and the porous sintered body of the present invention can utilize ceramic or glass in view of corrosion resistance and hardness. .

In the porous sintered body of the present invention, the coarse pore layer on the back side of the fine pore layer may further include two or more porous layers. Such a multi-layer structure of three or more layers can be appropriately used to secure a required strength and a designed thickness for the pore layer that exhibits a required function.

The porous sintered body of the present invention can be used as a reduced pressure adsorption member having the adsorption surface on the surface of the pore layer.
In particular, it can be used for an elevating / conveying device for adsorbing, picking up, transferring, and lowering an electronic component, and for this purpose, a wear-resistant hard porous sintered body is used.

The porous sintered body can be used as a filter member for fluid filtration. In this case, it is composed of a material having corrosion resistance to the fluid,
Also, by backing up the coarse pore layer with low fluid resistance,
There is an advantage that the thickness of the pore layer can be reduced and the flow resistance as a filter can be lowered. In this case, the porous layer side of the sintered body is used as a filtering surface, and it is used for filtration, but even for clogging during use of the filter, the cleaning fluid is allowed to flow backward through the coarse pore layer, Cleaning of the pore layer can be facilitated.

Further, the porous sintered body can be used as a sliding member which uses the surface of the fine pore layer as a sliding surface and uses the communication hole for impregnating lubricating oil. Such sliding members are used for sliding bearings, particularly oil-impregnated bearings, and have corrosion resistance as well as wear resistance for rotating shafts, and a fluid such as lubricating oil by adjusting the pore size distribution of the pore layer. The pore layer is adjusted to control the feed rate of

Basically, the porous sintered body of the present invention is manufactured by press-molding a fine-grained powder layer and a coarse-grained powder layer from powders having different particle sizes, and firing the compact. Then, a porous sintered body is formed integrally with the fine pore layer and the coarse pore layer.

As one of the embodiments, a fine-grained powder having a small grain size and a coarse-grained powder having a large grain size of a required material powder are prepared, and the fine grained powder is placed in a die for compacting. A fine-grained powder layer made of powder and a coarse-grained powder layer made of coarse-grained powder are filled so as to be vertically stacked. The two layers are arranged in contact. The two powder layers thus stacked are compressed in a mold by using a press or the like to be pressed into a green compact, and then the pressure molded body is fired at a required temperature to form a porous body. Use a high quality sintered body. The sintered body is formed by bonding a fine pore layer sintered from a fine grain powder layer and a coarse pore layer formed from a coarse grain powder layer to each other.

Another embodiment is a method in which two layers of a fine-grained powder layer and a coarse-grained powder layer are formed in a molding die, and the fine-grained powder layer and the coarse-grained powder layer are fired and sintered together with the molding die. Is used. Use a heat-resistant mold of desired shape, usually a carbon mold or a graphite mold, spread fine powder on the bottom of the mold to form a fine powder layer with a thin thickness, and then add coarse powder to the desired thickness. Is laid out to form a coarse-grained powder layer, which is then placed in a firing furnace and fired and sintered. After firing, the surface of the sintered fine pore layer of the fine powder layer is ground and used as a ground surface. If the mold is a flat mold, it can be made into a relatively flat molded body, and can be baked into a plate-shaped sintered product.

In another manufacturing method, a fine powder having a small particle size is filled in a mold to form a fine powder layer, which is compressed by a press to form a green compact having a required thickness. To do. Separately from this, a coarse powder having a large particle size is filled in a mold to form a green compact of a coarse powder layer. Then
A porous sintered body in which the green compact of the fine-grain powder layer and the green compact of the coarse-grain powder layer are superposed and then fired to be integrated, and the fine-pore layer and the coarse-pore layer are joined and integrated. To get

In this manufacturing method, when the green compact powder layer and the coarse powder layer are pressed against each other, the fine powder layer and the coarse powder layer are appropriately pressed by a press or the like. It is also possible to adopt a method of pressurizing and appropriately compression-molding.

As still another embodiment, a sintered body having a sintered fine pore layer and a sintered body having a coarse pore layer are separately prepared, and the fine pore layer It is also possible to obtain a porous sintered body in which the fine pore layer and the coarse pore layer are laminated and integrated by superposing the sintered body and the sintered body having the coarse pore layer and sintering again.

The sintering raw material used for producing the porous sintered body can be formed of a metal, particularly an alloy, as described above.
In addition, the porous sintered body of the present invention may use ceramic or glass from the viewpoint of corrosion resistance and hardness. In particular, in the above manufacturing method, in the method of firing and sintering the two layers of the fine-grained powder layer and the coarse-grained powder layer molded in the molding die, in the method of firing and sintering, each powder layer, In particular, it is preferable to use a material that can be sintered in the mold without pressure molding. Copper and its alloys, iron or steel, especially stainless steel, iron-based heat-resistant Alloys or other nickel or cobalt based refractory alloys or cobalt or nickel based sintered alloys, especially cobalt matrix WC cermets are available. Further, as the ceramic material, silicon nitride or sialon (Si-Al-O-N ceramic) is preferably used. From the material of these
A fine-grained powder having a controlled grain size and a coarse-grained powder are prepared and formed into the powder layer.

In the above-mentioned sintered material, it is preferable that the fine-grained powder and the coarse-grained powder are those whose particles have been previously sintered at a high temperature. Since each particle is preliminarily fired at a high temperature to be molded into a substantially spherical sintered particle, the two fine-grain powder layers and the coarse-grain powder layers are stacked in the molding die as described above. There is little sintering shrinkage in the layer during sintering, it is possible to prevent the occurrence of cracks and cracks in the sintered body, and the pore layer and the coarse pore layer have a uniform and stable sintered porous structure. There is an advantage that can be done.

In the above-described embodiment of the manufacturing method, it is possible to employ one in which the average particle size of the fine-grained powder is in the range of 50 to 200 μm and the average particle size of the coarse-grained powder is in the range of 200 to 1000 μm. . This particle size distribution of the coarse-grained powder and the coarse-grained powder determines the following dimensional range of the fine pore layer and the coarse-pore layer.
By setting m, the average pore diameter of the communicating pores of the pore layer is 40
It can be adjusted to the following range of μm. Further, by setting the average particle diameter of the coarse particle powder to 200 to 1000 μm, the average pore diameter of the coarse pore layer can be adjusted to 40 to 200 μm. It is preferable to set the lower limit of the particle size of the fine powder to 50 μm, but if the fine powder is smaller than this, the dimensional change at the time of compacting the sintered body becomes large, and it becomes difficult to control the size of the communicating holes of the fine pore layer. On the other hand, the grain size of coarse powder is 1000μ
When it exceeds m, the average pore size of the coarse pore layer tends to exceed 200 μm and becomes large, which is not preferable. The manufacturing method of the present invention is
A powder having such a particle size distribution is used to form a compact, which is fired to form a sintered body.

In the sintered body, the average pore diameter of the communication holes of the fine pore layer is preferably in the range of 10 to 40 μm, and the average pore diameter of the communication holes of the coarse pore layer is preferably in the range of 40 to 200 μm. The average pore diameter of the communicating pores of the fine pore layer may be minute depending on the intended use of the sintered body, but is preferably appropriately selected from the above range of 10 to 40 μm. If the average pore diameter of the pore layer is less than 10 μm, the passage resistance of the fluid becomes large depending on the application, which is not preferable, but from the viewpoint of washing the sintered body with the fluid,
Not preferable. The lower limit of the average pore diameter of the other coarse pore layer is 40μ
The reason for setting m is that if the average pore size is smaller than this, the effect of washing and removing foreign matter powder in the fine pore layer through the coarse pore layer is insufficient when the sintered body is washed. Preferably, the lower limit of the average pore diameter of the coarse pore layer is 50 μm or more, and particularly 6
Setting it to 0 μm or more facilitates the passage and removal of fine powder. If the upper limit exceeds 200 μm, in a sintered body with high porosity,
There is a fear that the strength for supporting the porous layer will be insufficient.
In this way, the preferable range of the average pore diameter of the coarse pore layer is
It is 50 to 200 μm.

Such a porous sintered body is ground to a desired surface shape and surface roughness including the surface of the pore layer. Then, cleaning is performed to remove clogging of pores in the fine pore layer due to grinding powder or the like. For cleaning, compressed air or pressurized water is supplied from the surface of the coarse pore layer toward the fine pore layer side, and fine powder of grinding dust in the pores of the fine pore layer is pushed out. Alternatively, ultrasonic cleaning may be performed by immersing in water, a cleaning liquid, or another liquid.

One form of cleaning is to use compressed air, for example, to supply compressed air from the side of the coarse pore layer,
The tip of the air nozzle is appropriately pressed against the surface of the coarse pore layer to supply compressed air, which is discharged from the surface of the fine pore layer to wash the inside of the fine pores of the fine pore layer. Since the fine pore layer can be thinly formed, fine particles of grinding dust can be easily removed from the fine pore layer. Pressurized water may be used instead of the pressurized air.

The porous sintered body in which the ground surface of the fine pore layer is prepared by laminating the fine pore layer and the coarse pore layer in this way can be used, for example, in an oil-impregnated bearing or a filter of a liquid or gas filter device. Used. Further, such a porous sintered body can be used as an adsorption plate of an adsorption device in which electronic components and other components are adsorbed under reduced pressure by an adsorption plate and transferred.

[0034]

[Example 1] In this example, a WC-15% Co-based sintered alloy powder was used as a Co-based sintered alloy for the sintering material. Sintered alloy powder is obtained by firing in a temperature range in which sintering is possible in advance and alloyed. Fine powder having a particle size of 100 to 180 μm and coarse powder having a particle size of 300 to 350 μm. A powder that falls within the range was prepared.

In-mold shape as shown in FIG. 1 80 mm × 80 m
On the bottom surface 50 of the carbonaceous mold 5 having a depth of 10 mm, the fine-grained powder having a thickness of about 2 mm is spread to form the fine-grained powder layer 20 (FIG. 1 (A)), and the coarse-grained powder is placed thereon. After filling, the upper surface 52 of the mold was filled up to the scraping to form the coarse-grained powder layer 30 (FIG. 1 (B)). Then, each mold 5 is charged into a sintering furnace, heated to a sintering temperature of 1350 ° C., held and fired (see FIG.
(C)), a sintered body 1 having a depth of 80 mm × 80 mm and a depth of 10 mm
Got The sintered body 1 was removed from the mold 5, and a diamond grindstone was used to grind the surface 21 of the pore layer 2 and the surface 31 of the coarse pore layer 3 on the opposite side by 0.5 mm (FIG. 1).
(D)).

The comparative example is the same as the example 1 except that the WC-1
A fine-grained powder layer 2 was prepared by using only fine-grained powder of a 5% Co-based sintered alloy powder to fill up to the upper surface scraping in a similar mold.
Only 0 is formed, and the mold is fired and sintered in the same manner.
Next, the front and back surfaces were similarly ground by 0.5 mm to give a comparative example.

The sample sintered bodies of Example 1 and Comparative Example were ultrasonically cleaned in the cleaning liquid twice, with the front surface and the back surface facing downward, respectively.

Further, in order to inspect the degree of cleaning, the front surface and the back surface are further turned downward, and once each, 20 times.
After ultrasonic cleaning for 1 minute, the presence or absence of residue was confirmed. The test results showed that no residue was found in the porous sintered body having a two-layer structure even after inspection and cleaning, but in the comparative example in which the pore layer was a single layer, the residue from inside the pore layer was still observed. confirmed.

[Example 2] WC-1 used in Example 1
Fine-grained powder of 5% Co-based sintered alloy powder (particle size 100 to 18
0 μm range), each separately from the mold 5a, the coarse particle powder layer 20 having an outer diameter of 80 mm × 80 mm and a thickness of 10 mm.
The porous green compact of was molded by pressing. Similarly,
Coarse-grained powder (grain size 300-350 μm range) to mold 5
From b, a porous green compact of the coarse-grained powder layer 30 having an outer shape of 80 mm × 80 mm and a thickness of 10 mm was formed by pressing. The compact of the fine grain powder layer 20 is 80 mm by wire processing.
It was cut out to a thickness of 2.5 mm with x80 mm (Fig. 2
(B)). The green compact of the fine-grained powder layer 20 that has been thinned is brought into contact with the compact of the coarse-grained powder layer 30 and sintered (see FIG. 2).
(D)), a two-layer sintered body (FIG. 2 (E)) in which the fine pore layer and the coarse pore layer are laminated and integrated.

The two-layer sintered body 1 has a surface 21 on the pore layer 2 side.
And the surface 31 on the side of the rough hole layer 3 were each ground by 0.5 mm with a diamond grindstone (FIG. 2 (F)), and ultrasonically cleaned in the same manner as in Example 1 above. Further, a cleaning test was conducted by an ultrasonic cleaning method in the same manner as in Example 1, but no residue of the pore layer was confirmed.

[0041]

The porous sintered body of the present invention is a sintered body composed of a porous sintered layer, and the sintered layer has a small-diameter communicating hole that opens and communicates with the surface of the sintered body. Since it is composed of a pore layer and a coarse pore layer having a large-diameter communicating hole which is connected to the communicating hole of the pore layer and communicates with each other, the pores required for the application of the porous sintered body are It is possible to select a combination of a thin pore layer having a pore size and a coarse pore layer that strengthens the back, and even if clogging due to grinding of the pore layer surface or clogging during use occurs, it can be easily removed by washing, There is an advantage that the porous layer can be regenerated.

If a cobalt- or nickel-based sintered alloy is used for the porous sintered body, the sintered body can be endowed with heat resistance, corrosion resistance, high temperature strength, and especially wear resistance. Further, when the average pore diameter of the communication holes of the fine pore layer is in the range of 10 to 40 μm and the average pore diameter of the communication holes of the coarse pore layer is in the range of 40 to 20 μm, fine particles that tend to be blocked during grinding or during use. By appropriately washing the pore layer, the pore layer can be suitably used within the above pore size range.

When the porous sintered body of the present invention is used as a reduced pressure adsorption member having the surface of the fine pore layer of the porous sintered body as the adsorption surface, the pore diameter of the fine pore layer becomes small, so that the adsorption surface Can be made smooth, and a smooth surface can be held without giving protrusions or other surface damage to the mating member to be attracted.
Further, there is an advantage that the adsorption surface can be easily regenerated because the pore layer is clogged due to suction during use and can be easily washed through the coarse pore layer.

When the porous sintered body of the present invention is used as a filter member for fluid filtration, it is used for filtration with the pore layer side of the sintered body as the filtration surface, but clogging occurs during use of the filter. However, the cleaning of the fine pore layer can be facilitated by backflowing the cleaning fluid through the coarse pore layer.

If the porous sintered body is used as a sliding member in which the surface of the fine pore layer is used as the sliding surface and the communication hole is used for impregnating the lubricating oil, the inside of the coarse pore layer is used. Lubricating oil can be supplied to the sliding surface, the pore layer can be made thin, and the distance between the communicating holes that are adjacent to each other in the pore layer can be narrowed. There is an advantage that it can be stably supplied to the sliding surface without causing

In the method for producing a porous sintered body of the present invention, a fine grain powder layer made of fine grain powder and a coarse grain powder layer made of coarse grain powder are filled in a mold so as to be in contact with each other. A porous sintered body obtained by molding, and then firing the molded body to bond a fine pore layer sintered from a fine grain powder layer and a coarse pore layer sintered from a coarse grain powder layer in the sintered body. To form a surface by grinding the pore layer, in particular, the molded body, without releasing from the mold, is fired at the sintering temperature for each mold.
Since it is sintered into a porous sintered body, the sintering procedure is simple, and the fine pore layer and the coarse pore layer have a sufficiently strong sintered body even if the porosity of the sintered body is increased, If fine-grained powder and coarse-grained powder are sintered powder of a cobalt-based or nickel-based sintered alloy,
A porous sintered body having a high sintering rate between particles, a relatively small sintering shrinkage, and a high porosity can be obtained.

Particularly, the average particle diameter of the fine powder is 50 to 200.
The average particle size of the coarse powder is 200
By setting it in the range of up to 1000 μm, it becomes easy to control the average pore diameter of the fine pore layer and the coarse pore layer through the sintering process,
There is an advantage that the fine pore layer can be properly supported by the coarse pore layer, and the fine pore layer can be easily set.

Further, the average pore diameter of the communicating pores in the fine pore layer is 10
If the average pore diameter of the communication holes of the coarse pore layer is in the range of 40 to 200 μm, the pore layer that tends to be clogged during grinding or use can be appropriately and easily washed, A porous sintered body that can be suitably used in the above pore size range can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a manufacturing process of a porous sintered body according to an example of the present invention (A to D).

FIG. 2 is a schematic cross-sectional view showing a manufacturing process of a porous sintered body according to another embodiment of the present invention (A to F).

[Explanation of symbols]

1 Porous sintered body 2 Pore layer 20 Fine-grained powder layer 3 Coarse pore layer 30 coarse-grained powder layer 5 Mold

Claims (14)

[Claims] 1. A sintered body comprising a porous sintered layer, wherein the sintered layer has a pore layer having a small-diameter communicating hole that is open and communicates with the surface of the sintered body, and the pore layer communicates with the pore layer. A porous sintered body comprising: a coarse pore layer having a large diameter communicating hole that is connected to the hole and communicates with each other. 2. The porous sintered body according to claim 1, wherein the sintered body is a cobalt-based or nickel-based sintered alloy. 3. The average pore diameter of the communicating pores of the fine pore layer is 10 to 40.
It is in the range of μm, and the average pore diameter of the communication pores of the coarse pore layer is 40 to
The porous sintered body according to claim 1 or 2, which has a range of 200 μm. 4. The porous sintered body according to claim 1, wherein the surface of the pore layer is a ground surface. 5. A reduced pressure adsorption member having an adsorption surface on the surface of a pore layer of the porous sintered body of the porous sintered body according to claim 1. 6. A filter member for fluid filtration, comprising the porous sintered body according to claim 1. 7. A sliding member comprising the porous sintered body according to claim 1, wherein the surface of the pore layer is a sliding surface, and the communicating hole is used for lubricating oil impregnation. 8. A method for producing a sintered body comprising a porous sintered layer, wherein a fine-grained powder layer made of fine-grained powder and a coarse-grained powder layer made of coarse-grained powder are contacted with each other in a mold. To form a porous body in which a fine pore layer sintered from a fine-grain powder layer and a coarse pore layer sintered from a coarse-grain powder layer are bonded in the sintered body. A method for producing a porous sintered body, which comprises forming a porous sintered body and grinding a fine pore layer to form a surface. 9. The manufacturing method according to claim 8, wherein the molded body is sintered together with the molding die at a sintering temperature without being released from the molding die to sinter into a porous sintered body. 10. A fine-grained powder layer made of fine-grained powder is pressure-formed, a coarse-grained powder layer made of coarse-grained powder is pressure-formed, and the fine-grained powder layer and the coarse-grained powder layer are joined together. A method for manufacturing a porous sintered body, which is fired and integrally sintered. 11. The manufacturing method according to claim 8, wherein the fine-grained powder and the coarse-grained powder are sintered powders of a cobalt-based or nickel-based sintered alloy. 12. The average particle size of fine powder is 50 to 200 μm.
m, and the average particle diameter of the coarse powder is 200 to
The manufacturing method according to any one of claims 8 to 10, which is in a range of 1000 µm. 13. The average pore diameter of the communicating pores of the pore layer is 10 to 4
It is in the range of 0 μm, and the average pore diameter of the communicating pores of the coarse pore layer is 40
It is the range of -200 micrometers, The manufacturing method in any one of Claim 8 thru | or 12. 14. The manufacturing method according to claim 8, wherein the communicating holes of the pore layer of the porous sintered body are washed.