JPH08302404A - Composite layer metallic porous body and its manufacture - Google Patents

Abstract

PURPOSE: To provide a metallic porous body having a laminated structure consisting of a plurality of layers of different pore distribution, and its manufacturing method. CONSTITUTION: A composite layer porous body is manufactured as a hot isostatically pressed sintered body by either the process (a) where plural kinds of the metallic powder, the powder compact or the metallic powder combined with the powder compact of different material and/or different grain size are layered (lamination filling) as the layer forming materials to achieve the hot isostatic pressing treatment (HIP treatment), or the process (b) where the layer forming materials are layered (lamination filling), and the HIP treatment is achieved after the cold isostatic pressing treatment. The HIP treatment in the process (a) is preferably achieved under the condition that the temperature is 0.2-0.85mpK [mpK is the melting point (absolute temperature) of the powder] and the pressure is 0.5-150MPa, while the HIP treatment in the process (b) is preferably achieved under the condition where the temperature is 0.5-0.98mpK, and the pressure is 0.5-150MPa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous metal material useful as a filter material, a catalyst carrier, a metal casting mold, a plastic molding mold, a heat insulating material, a soundproofing material, and a method for producing the same.

[0002]

2. Description of the Related Art A porous metal body used for the above-mentioned various uses is a method in which a mixture of metal powder and a metal fiber such as stainless steel is pressure-molded into a desired shape and then heat-sintered. Alternatively, it is produced by a method in which an appropriate amount of a binder, a solvent and the like are added to metal powder to prepare a slurry, the binder and the solvent are removed by preliminary firing, and then sintering is performed by firing. Further, as a method for producing a metal porous body as a multi-layered porous body having a laminated structure composed of a plurality of layers having different pore distributions, a metal powder or a metal fiber is mixed with a heat-dissipating fiber at different mixing ratios. There has been proposed a method in which a plurality of the above-mentioned molded bodies are pressure-molded, the molded bodies are laminated and heated and sintered (Japanese Patent Application Laid-Open No. 63-171803).

[0003]

In the conventional method for producing a porous metal body, the raw material powder is pressure-molded and then the green body is sintered by pressureless sintering. However, in the manufacturing process, it is difficult to control the pore characteristics such as porosity and pore diameter of the obtained porous metal body. Further, it is difficult to secure the strength in the case of a porous body manufactured by using a raw material having poor moldability, and it is not easy to secure the bonding strength at the laminated interface in a multi-layer porous body. The present invention relates to a multi-layer metal porous body having a laminated structure composed of a plurality of layers having different pore characteristics, each layer having a required pore distribution, and a multi-layer metal porous body in which the bonding strength between layers is also secured, and The manufacturing method is provided.

[0004]

The multi-layer metal porous body of the present invention is a hot isotropic pressure sintered body having a laminated structure composed of a plurality of porous metal layers having different pore distributions. I am trying. The multi-layer metal porous body of the present invention is obtained by (a) filling a plurality of kinds of metal powders having different particle sizes and / or grades into a layer (lamination filling), or preliminarily press-molding the metal powder. A method of laminating and filling a plurality of formed powder compacts, or laminating and filling a metal powder and a powder compact, and then sintering by hot isostatic pressing (hereinafter also referred to as "HIP treatment"), ( b) A plurality of kinds of metal powders having different particle sizes and / or grades are packed in layers (lamination and packing), or a plurality of powder compacts formed by subjecting the metal powders to pressure molding in advance are stacked and packed. Alternatively, the metal powder and the powder compact are laminated and filled, and after cold pressing, H
It can be manufactured by a method of subjecting to IP treatment and sintering.

[0005]

[Function] Based on the difference in material type, particle size, etc. of each layer by layer-filling (laminating and packing) metal powders (or powder compacts, etc.) having different material types, particle sizes, etc. Thus, a porous sintered body having a laminated structure composed of a plurality of layers having different pore distributions can be obtained. HI for the sintering process
Since the P treatment method is applied, the effect that the sintering reaction is performed under the isotropic pressure action is that good homogeneity is imparted to the multilayer porous sintered body, the bonding between particles is strengthened, and Even if the laminated structure has a high strength as a material and a combination of different material types, good bonding strength is given to the layer interface.

The porosity, open porosity, average pore size, and other pore distributions (pore characteristics) of each layer of the multilayer sintered body are determined by the type and grain size of the constituent material of each layer, and the cold addition of the layer material to the laminated packing. Presence or absence of pressure treatment and its treatment condition, and HIP treatment condition (temperature,
It can be controlled over a wide range by the applied pressure, processing time, etc. For example, when a porous body used as a filter or the like is required to have a particularly large wall thickness, only the surface layer portion is a porous layer having a relatively small pore diameter, and the inside is a porous body having a large pore diameter. By providing a gradient of pore distribution as a porous layer, unlike a porous body that has the pore size required for the entire wall thickness, it is possible to reduce pressure loss as much as possible and to secure a higher filter function. become.

Further, in the present invention in which a multilayer porous body is manufactured as a sintered body by HIP treatment, there is a high degree of freedom in selecting the layer material constituting each layer, and layer materials of various material types and particle sizes can be used.
The multi-layer porous body can be widely selected depending on the use and usage of the multi-layer porous body. This makes it easy to meet the requirements of material properties (for example, heat resistance, corrosion resistance, wear resistance, etc.) necessary for various usage environments, and the required properties can be economically advantageously satisfied. This means that the applications of porous materials can be expanded and diversified. For example, when high temperature strength is required for the surface layer portion of the porous body and other portions do not require such high temperature strength, the layer material with high temperature strength is applied only to the surface layer, and the remaining layer is By applying a relatively inexpensive layer material, it is possible to economically manufacture a multi-layer porous body suitable for the purpose.

The layer material of each layer forming the multi-layer porous body of the present invention may be, for example, stainless steel (SUS304, 630, etc.), tool steel (SKD11, SKD11,
61 etc.), maraging steel (18Ni series, 20Ni
System), high speed steel (SKH51, 55, etc.), non-ferrous metal (Al alloy, Ti alloy, Ni alloy, Co alloy, etc.), and various materials can be selected and used over a wide range. The particle size of the powder ranges from a fine particle size to a coarse particle size (for example, from submicron order to several hundreds of microns), including various particle sizes that are commercially available. Can be appropriately selected and used in combination depending on the pore characteristics of

As the layer-constituting material, materials having different material types / grain sizes are powdered as they are, or the powder is preliminarily pressure-molded into a powder compact to be laminated and filled, or a combination of the powder and the powder compact is laminated. After the filling, the laminated packing is subjected to the HIP treatment as it is [the step a], or the laminated filling is subjected to the cold pressure treatment and then the HIP treatment is carried out [the step b] to obtain the multilayer porosity. Baked into a quality sintered body. In each of the above steps, the powder compact when the powder compact is used as the layer material is preferably formed by the cold isostatic pressing method (CIP molding method) from the viewpoint of good homogeneity. used. The CIP molding is about 20
It can be performed by applying a pressure of 490 MPa (300 to 5000 atm). In addition, in the case of performing cold pressure treatment prior to HIP treatment after filling powders or powder compacts in a layered manner (step b above), the cold pressure compaction treatment also requires CIP from the viewpoint of ensuring homogeneity. A treatment method is preferably adopted. The pressure molding process is performed at about 20 to 490 MPa (300 to 5,000 MPa).
(Atmospheric pressure) is applied.

The sintering reaction conditions such as temperature and pressure in the HIP treatment of the laminated packing are determined by the type of layer material and its combination,
And controlled according to desired pore characteristics and the like. In the case where the laminated filling body of the capsules is subjected to the HIP treatment as it is without being subjected to the cold pressure treatment, the treatment temperature is:
0.2 to 0.85 mpK [mpK is the melting point (absolute temperature) of the metal powder, in the case of a combination of different materials, the melting point of the low melting point powder], the pressing force: adjusted to a range of about 0.5 to 150 MPa. Is preferred. At lower temperature and lower pressure,
Insufficient sintering reaction (insufficient interparticle bonding) is likely to occur, while treatment at a higher temperature and higher pressure may damage the porosity due to excessive progress of the sintering reaction. The processing time is
It may be about 0.5 to 5 hours. The multilayer sintered body obtained by the HIP treatment is optionally subjected to a heat treatment (strengthening heat treatment) for strengthening the interparticle bond. Its heat treatment takes out a sintered body from the capsule, or may be carried out as it is without removing the capsule, temperature: 0.
It is successfully achieved by holding at 5 to 0.98 mpK for a suitable time (about 2 to 12 hours).

On the other hand, after the laminated packing is subjected to cold pressure treatment,
In the case of HIP treatment (step b), it is preferable that the multi-layered powder compact formed by the cold pressure treatment is not encapsulated in the capsule but is left naked (capsule-free) for the HIP treatment. . This way, HI using capsules
Unlike the P treatment, the hydrostatic pressure medium penetrates into the internal ventilation holes of the multi-layer powder compact (there are a large number of multi-vent holes in the compact), so that the pressurizing action of the hydrostatic pressure medium is It is added not only from the outside of the molded body but also from the inside. As an effect thereof, it is possible to carry out sintering without pressurizing the continuous air holes, and it is also possible to set the HIP treatment temperature at a high temperature and strengthen the interparticle bond without impairing the pore characteristics. The HIP treatment is performed at a treatment temperature of 0.5 to 0.98 m.
pK [mpK has the same meaning as above], applied pressure: about 0.5 to 1
It is preferable to adjust the pressure in the range of 50 MPa. Treatments at lower temperatures and lower pressures tend to cause insufficient sintering reactions (lack of interparticle bonding), while treatments at higher temperatures and higher pressures lead to excessive sintering reactions and lower porosity. May cause The processing time may be about 0.5 to 5 hours. As described above, since a high temperature can be applied to the HIP treatment to promote interparticle bonding due to the sintering reaction, unlike the sintered body of the step a, strengthening of the sintered body after the HIP treatment is performed. No heat treatment is specifically required. However,
The strengthening heat treatment is not excluded, and the strength of the sintered body can be further increased by adding the treatment if necessary. The processing may be performed under the same conditions as above.

[0012]

[Example 1]

-Layered filling of powder → HIP treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (grain size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
Underflow) (2) as shown in stacked filling and sintering and heat treatment Figure 1, the capsule 1 _1, the powder, L
11 layers (powder M1) and L12 layer (powder M2) are stacked and filled in two layers, degassed and sealed (1 x 10 ^-2 Torr), and HIP.
By subjecting it to a treatment, a thick plate block-shaped multilayer porous sintered body is obtained. Sintered body size: 100 × 100 × 100 (mm) [L11 layer thickness 50, L12 layer thickness 50, mm].

[Example 2] -Layered filling of powder-> HIP treatment-> Reinforcement heat treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
Underflow) (2) as shown in stacked filling and sintering and heat treatment Figure 1, the capsule 1 _1, the powder, L
11 layers (powder M1) and L12 layer (powder M2) are stacked and filled in two layers, degassed and sealed (1 x 10 ^-2 Torr), and HIP.
By subjecting it to a treatment, a thick plate block-shaped multilayer porous sintered body is obtained. After removing the capsules, the sintered body is subjected to a strengthening heat treatment. Sintered body size: 100 × 100 × 100 (mm) [L11 layer thickness 50, L12 layer thickness 50, mm].

[Example 3] -Powder layer-filling-> HIP treatment-> Reinforcement heat treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M3: Inconel 625 alloy powder (grain size 100 mesh, under) (2) Layer-filling, sintering process and heat treatment As shown in FIG. 2, the space inside the capsule 1 ₁ is divided into two parts by the partition plate 3 ₁ and the above. The powder is laminated and packed into two layers, an L21 layer (powder M1) and an L22 layer (powder M3), and a partition plate 3 ₁
Pull out. After degassing and sealing (1 × 10 ^-2 Torr), HIP treatment is performed to obtain a thick plate block-shaped multilayer porous sintered body. The capsule is removed, and the sintered body is subjected to a strengthening heat treatment. Sintered body size: 100 × 100 × 100 (mm) [L21 layer thickness 50, L22 layer thickness 50, mm].

[Example 4] -Powder layer stack filling-> HIP treatment-> Reinforcement heat treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
(2) Layer-filling, sintering process and heat treatment As shown in FIG. 3, the cylindrical capsule 1 ₂ (inner cylindrical wall W1)
And an outer cylindrical wall having a toroidal annular space formed by W2) annular space, divided into two spaces concentrically with the partition plate 3 _2, the powder L31 layer and (powder M1) L32 layer (powder M2 2) is stacked and filled, and then the partition plate 3 ₂ is removed. After degassing and sealing (1 × 10 ^-2 Torr), the sample is subjected to HIP treatment to obtain a hollow cylindrical multilayer porous sintered body, the capsule is removed, and a strengthening heat treatment is performed. Sintered body size: outer diameter 150 x inner diameter 50 x length 150 (m
m) [Inner L31 layer thickness 25, Outer L32 layer thickness 25, mm]

[Example 5] -Layer filling of powder compact and powder → HIP treatment (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M3: Inconnel 625 Ni-based alloy powder (80Ni-14Cr-6F)
e) (Particle size 60 mesh / under) (2) Pressure molding of powder compacts Powder M1 is filled in a rubber mold and CIP molded (pressing force: 1200)
Atmospheric pressure) forms a powder compact (rectangular block). (3) the powder compact and powder layering filling and sintering process the powder compact with (M1), and a powder M3, as shown in FIG. 4, the capsule 1 in _1, L41 layer (powder compact M1)
And L42 layer (powder M3) surrounding the same were filled in a two-layer laminated state, degassed and sealed (1 × 10 ^-2 Torr), and then HI
Subjected to P treatment to obtain a thick plate block-shaped multi-layer porous sintered body, and after removing the capsules, strengthening heat treatment is performed. Sintered body size: 100 × 100 × 100 (mm) [L41 layer thickness 50 × 50, L42 layer thickness 25, mm].

[Example 6] -Powder layer-filling-> Cold pressure molding-> HIP treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
(Under) (2) Laminate filling of powder and pressure molding As shown in FIG. 5, a rubber mold 2 combined with a cylindrical core metal 4
_In the annular space of ₁ , the above-mentioned two kinds of powder, L51 layer (powder M
1) and L52 layer (powder M2) are stacked and filled in two layers above and below, and CI
A multi-layered powder compact is obtained by P compacting (pressing force: 1200 atm). (3) Sintering treatment The above multi-layered powder compact is HIP-treated (capsule-free)
Then, a hollow cylindrical multi-layer porous sintered body is obtained. Sintered body size: outer diameter 60 x inner diameter 30 x length 150 (mm)
[L51 layer thickness 75, L52 layer thickness 75, mm]

[Example 7] -Layer loading of powder compacts-> Cold pressure compaction-> HIP treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
(2) Formation of Powder Forming Body Each of the powders M1 and M2 is filled in a rubber mold and CI.
P treatment (pressurizing force: 1200 atm) is performed to form two powder compacts (M1) (M2). (3) cold pressure treatment the two powder compacts of the powder compacts (M1) (M2), as shown in FIG. 6, stacked filled in a rubber mold 2 _1, CIP treatment (pressure:
1500 atm) is applied to integrate the two into a multilayer powder compact. (4) Sintering treatment The above composite powder compact is HIP treated (capsule free)
Then, a multilayer porous sintered body having a thick plate block is obtained. Sintered body size: 100 × 100 × 100 (mm) [L61 layer thickness 50, L62 layer thickness 50, mm].

[Embodiment 8] -Layer filling of powder compact and powder-> cold pressure compaction-> HIP
Treatment- (1) Layer material powder M1: SUS 316L stainless steel powder (grain size 100 mesh /
Under) M3: Inconnel 625Ni-based alloy powder (80Ni-14Cr-6F)
e) (Particle size 60 mesh / under) (2) Pressure molding of powder compacts Hollow cylindrical shape consisting of powder M1 by CIP treatment (pressing force: 1200 atm) using a rubber mold combined with a cylindrical core metal To form a powder compact. (3) Layer-filling and cold press molding of powder compact and powder The above cylindrical powder compact (M1) and powder (M2) are shown in FIG.
As shown in Fig. 2, a rubber mold 2 ₂ having a donut-shaped annular space
L71 layer (powder compact M1) and L72 layer (powder M2)
Are stacked and filled in two layers forming concentric circles, and CIP treatment (pressing pressure: 1500 atm) is performed to form a multilayer powder compact. (4) Sintering treatment The above multi-layered powder compact is HIP treated (capsule free)
Then, a multilayer porous sintered body having a concentric two-layer laminated structure is obtained. Sintered body size: outer diameter 150 x inner diameter 50 x length 100,
(Mm) [L71 layer thickness 25, L72 layer thickness 25, mm].

[Comparative Example] -Layer filling of powder->Pressure-molding-> Normal pressure sintering- (1) Layer material powder M1: SUS 316L stainless steel powder (particle size 100 mesh
Under) M2: SUS 316L stainless steel powder (grain size 40 mesh,
(2) Molding and Sintering Treatment of Powder Molded Body The above-mentioned two kinds of powders are laminated in a rubber mold to form two upper and lower layers (L01 layer and L02 layer) (a lamination mode similar to FIG. 1). ) And CIP treatment (pressurizing force: 100 MPa) to form a two-layered multilayer powder compact. Then, it is subjected to atmospheric pressure sintering treatment (atmosphere: air) to obtain a multilayer porous sintered body. Sintered body size: 100 × 100 × 100 (mm) [L01 layer thickness 50, L02 layer thickness 50, mm].

Table 1 shows the manufacturing conditions of the multi-layered porous sintered bodies of the respective examples and comparative examples, and Table 2 shows the results of measurement of various characteristics of the obtained product sintered bodies. "Degassing" in the table
Is the permeation pressure of air in the direction of penetrating the two laminated layers, and “tensile strength” and “elongation” are the test pieces so that the interface between the two layers is located at the center from the sintered body. The measurement results of a tensile test that was taken and conformed to JIS Z2241 are shown. The multi-layer porous body of the present invention has a porosity / open porosity of each porous layer, and a different pore distribution of the average pore diameter, and is equal to or more than the multi-layer porous body produced by the conventional method. It has porosity characteristics such as degassing and has improved mechanical properties such as strength and elongation.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

The multi-layer porous body obtained as the hot isostatically pressed sintered body of the present invention has a laminated structure composed of a plurality of porous layers having different pore characteristics, and the particles in each layer are The bonding strength between layers is also high. The type of layer material that forms each layer can be widely selected, and the pore characteristics and material characteristics required depending on the application and use mode, etc., depending on the layer material, particle size, and sintering conditions of hot isostatic pressing. Can be economically satisfied. Further, regardless of the shape and size, good homogeneity can be guaranteed, and rational multilayer structure design and various variations can be adopted according to the application and usage. Form, function,
These features related to economy and the like enable expansion and diversification of uses of the porous metal body, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an example of a stack filling method of raw material powders.

FIG. 2 is an explanatory cross-sectional view showing an example of a stacking and filling manner of raw material powders.

FIG. 3 is a perspective explanatory view showing an example of stacking and filling of raw material powders.

FIG. 4 is a cross-sectional explanatory view showing an example of a layered filling state of a raw material powder and a powder compact.

FIG. 5 is a perspective explanatory view showing an example of a stack filling mode of a powder compact.

FIG. 6 is an explanatory cross-sectional view showing an example of stacking and filling of raw material powder.

FIG. 7 is a perspective explanatory view showing an example of stacking and filling of raw material powder and powder compact.

[Explanation of symbols]

1 _1, 1 ₂ : Capsule for hot isostatic pressing 2 _1, 2 ₂ : Rubber mold for cold pressing 3 _1, 3 ₂ : Partition plate 4: Core metal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Tanaka 1-1-1, Nakanomiya Oike, Hirakata-shi, Osaka Prefecture Kubota Hirakata Factory

Claims (7)

[Claims] 1. A multi-layer metal porous body, which is a hot isotropically pressurized sintered body having a laminated structure composed of a plurality of porous metal layers having different pore distributions. 2. A plurality of types of metal powders having different grain sizes and / or grades, a metal powder and a metal powder compact, or a plurality of metal powder compacts are stacked and filled, and hot isostatic pressing is performed. Sintering, The manufacturing method of the multilayer porous body of Claim 1 characterized by the above-mentioned. 3. The hot isotropic pressure treatment is performed at a temperature of 0.2 to.
0.85 mp K (where mp K is the melting point (absolute temperature) of the powder, the melting point of the low melting point powder when the powders of different materials are stacked and filled), and the pressure: 0.5 to 150 MPa It carries out, The manufacturing method of the multilayer metal porous body of Claim 2 characterized by the above-mentioned. 4. The multilayer porous body according to claim 2 or 3, wherein after the hot isostatic pressing treatment, a heat treatment for strengthening the interparticle bond of the sintered body is performed. Manufacturing method. 5. The heat treatment is performed at a temperature of 0.5 to 0.98 mp.
The method for producing a multilayer metal porous body according to claim 4, wherein K is performed. 6. A plurality of types of metal powders having different particle sizes and / or grades, metal powders and metal powder compacts, or a plurality of metal powder compacts are laminated and filled, and after cold press treatment, The method for producing a multilayer metal porous body according to claim 1, wherein the sintering is performed by hot isostatic pressing. 7. The hot isostatic pressing treatment is performed at a temperature of 0.5 to 0.5.
0.98 mp K (where mp K is the melting point of powder (absolute temperature), the melting point of low melting point powder (absolute temperature) when different types of powder are stacked and filled), and pressure: 0.5 to 150
The method for producing a multilayer metal porous body according to claim 6, wherein the method is performed under a condition of MPa.