JP2764669B2 - Manufacturing method of sintered aluminum porous material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered aluminum porous material, and more particularly to an oxidizing component contained in a carbon container when a raw material aluminum powder or the like is filled in a carbon container and sintered. The present invention relates to a method for producing a sintered aluminum porous material that can prevent surface oxidation of a sintered body and obtain a sintered body having a small variation in quality by using a container in which sintering is previously released.

[0002]

2. Description of the Related Art Sintered porous aluminum materials are said to be useful for applications such as sound absorbing materials. This is because it is presumed that even when wave energy such as sound waves passes through the passage because the aluminum sintered porous material has a passage formed of a communication hole, the wave energy is absorbed during the passage, and the porous material has a sound absorbing material. There are excellent characteristics as.

[0003] However, the surface of aluminum powder is easily oxidized and sintering is very difficult, and sintering is not possible or the quality varies even if sintering is possible depending on the atmospheric conditions. It is known. As a method for producing a sintered porous material using such aluminum powder, for example, Japanese Patent Publication No. 60-47322 discloses C
u, Mg, Si, or an alloy containing one or more of these metals, or a powder of aluminum or an alloy thereof mixed with two or more powders, and then molded into a required shape without pressure. Then, there is a method of sintering in a non-oxidizing atmosphere near the melting point of aluminum or its alloy.

[0004] Further, when producing this sintered aluminum porous material, there is a method in which a ceramic material is overcoated on the surface of a carbon material such as graphite as a container for filling the aluminum powder.

[0005] In any of these methods, carbon does not form a carbon compound in the sintering process with aluminum or steel.
It is the most suitable vessel for producing sintered porous material. Also,
Carbon materials such as graphite have been considered to be the most suitable materials because of their excellent thermal conductivity, good workability, low specific gravity, and low brittleness. However, when producing a sintered porous material from aluminum powder, a carbon material such as graphite, which is a container filled with the powder, frequently occludes oxygen and moisture in the atmosphere.
There has been a problem that the surface of the porous material is oxidized to cause discoloration of black-brown containing aluminum oxide as a main component, and that the porous material is not formed, so that a porous material of good quality cannot be produced.

[0006]

That is, an object of the present invention is to solve the above-mentioned problems. More specifically, the present invention prevents the oxidation of a carbon container when producing a sintered porous material of aluminum. An object of the present invention is to provide a method for efficiently producing a sintered aluminum porous material by improving the bonding state during sintering.

[0007]

Means for Solving the Problems The present invention fills a carbon container with powder of aluminum or a mixture of aluminum and an alloy and sinters it in a non-oxidizing atmosphere to produce a porous material. It is characterized in that an oxidized component such as oxygen or moisture to be occluded is released in advance by a heat treatment and / or a vacuum treatment.

Hereinafter, the configuration and operation as the means of the present invention will be described as follows.

The present inventors have studied a container in which aluminum powder or the like is filled and sintered when producing a sintered aluminum porous material. When the material of the container is metallic, aluminum and an alloy are used. It is easy to make, so it is not possible to take out the sintered porous material from the container after sintering. Also, there is a method of coating nonmetallic ceramics such as hollow on a metal base, Or
At a high temperature, the ceramic is peeled off, which is not practically suitable for producing a sintered aluminum porous material.

[0010] In addition, carbon such as graphite is an excellent material having good thermal conductivity and not forming an alloy of aluminum and carbon. However, when this is used as a container, it is easy to occlude air or moisture, and it takes several hours. Simply leaving it in the air makes it unsuitable for producing a sintered aluminum powder porous material.

For example, although the oxidized state of the atmosphere can be grasped by the presence of moisture, it is possible to measure the dew point and obtain a good sintered aluminum powder porous material even if the reducing atmosphere is maintained at about −20 ° C. Cannot be manufactured.

Thus, it has been found that a good aluminum sintered body cannot be obtained unless the state of the atmosphere is maintained at a dew point used for measuring the degree of oxidation in the atmosphere at around -40 to -60 ° C. Although the decrease in the dew point largely depends on the structure of the furnace, the present invention has been achieved by focusing on the fact that the dew point is reduced by a carbon container such as graphite.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view showing an example of an apparatus used in carrying out the present invention, and FIG. 2 is a perspective view of a graphite container used in the apparatus shown in FIG. 1 is a graphite container, 2
Is a stacked graphite container, 3 is a sintering furnace, 4 is a door, 5 is a low
La and 6 show concave dents.

First, the graphite container 1 shown in FIG. 2 has a concave dent 6 in the container, and the concave dent 6 is filled with aluminum powder or the like without pressure. Next, the stacked graphite containers 2 shown in FIG. 1 are inserted into the entrance 4 of the sintering furnace 3 and into the door 4, and the sintering is performed while moving from the door 4 of the sintering furnace 3 onto the rollers 5 in the furnace. Then, it is discharged out of the system from the door 4 of the sintering furnace 3. Each door 4 of the sintering furnace 3 is configured to be slidable upward by inserting the stacked graphite containers 2 to prevent oxidation of the atmosphere. Graphite container 2 once long (period)
If the graphite container 2 is used as it is when exposed to the atmosphere, the continuously stacked graphite containers 2 move into the furnace, so that the oxygen and moisture occluded in the graphite containers are reduced to the reducing atmosphere. The state becomes an oxidizing atmosphere, which hinders the sintering reaction of the aluminum powder.

Therefore, such a problem can be prevented by performing heating and / or vacuum treatment before using the graphite container 1 to remove oxygen and moisture occluded in the graphite container. .

A preferred example of the present invention is to heat at 600 ° C. for 2 hours in a non-oxidizing atmosphere or at 100 ° C. for about 30 hours, or place in a vacuum furnace at about 10 ⁻² Torr at 600 ° C. for 2 hours and at 100 ° C. for 10 hours. Oxidation components such as oxygen and moisture can be extracted from the graphite container 2 by holding the same in a vacuum furnace for a time, and the aluminum powder is continuously processed by the sintering furnace 3 using the pretreated graphite container. After sintering, an aluminum sintered porous material having a color tone of aluminum itself without discoloration such as brown can be obtained. According to the present invention, since the dew point in the sintering furnace can be maintained at -40 to -60 ° C, an aluminum sintered porous material having high sinterability can be obtained.

Embodiment 1 Prior to the sintering step, the carbon container shown in FIG.
Heating was performed for an hour to release oxidized components such as oxygen and moisture stored in the carbon container. Next, this container is filled with aluminum powder, stacked as shown in FIG. 1, and moved in a sintering furnace in which the dew point is maintained at −40 to −60 ° C., and a sintered aluminum porous material having high sinterability is obtained. I got

Embodiment 2 FIG. Preheat the carbon container to a temperature of 100
The same operation as in Example 1 was carried out except that the treatment was carried out at 30 ° C. for 30 hours, and the same results as in Example 1 were obtained.

Embodiment 3 FIG. The same results as in Example 1 were obtained, except that the carbon container was previously treated in a vacuum furnace at 600 ° C. for 2 hours at 600 ° C. in a vacuum furnace at a degree of vacuum of about 10 ⁻² Torr. I got

Embodiment 4 FIG. Operating conditions of the vacuum furnace were 10 ^-2 To
The same operation as in Example 3 was carried out except that the treatment was carried out at rr and 100 ° C. for about 10 hours, and the same results as in Example 3 were obtained.

[0022]

As described above in detail, the present invention provides a method of filling a powder of aluminum or a mixture of aluminum and an alloy in a carbon container and sintering the same in a non-oxidizing atmosphere to produce a porous material. It is characterized in that an oxidizing component such as oxygen and moisture stored in a carbon container is released in advance by heat treatment and / or vacuum treatment.

According to the present invention, when producing a sintered aluminum powder porous material, a graphite container from which oxidizing components such as oxygen and hydrogen have been removed is filled with aluminum powder and the like and sintered in a non-oxidizing atmosphere. As a result, a porous material having the color tone of aluminum itself without discoloration such as brown can be obtained.

The dew point in the sintering furnace is set at -40 to -60 ° C.
, So that an aluminum porous material having high sinterability can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of an apparatus used when carrying out the present invention.

FIG. 2 is a perspective view of a graphite container used in the apparatus of FIG.

[Explanation of symbols]

 Reference Signs List 1 graphite container 2 stacked graphite containers 3 sintering furnace 4 door 5 roller 6 concave dent

Claims (2)

(57) [Claims] 1. A method in which a powder of aluminum or a mixture of aluminum and an alloy is filled in a carbon container and sintered in a non-oxidizing atmosphere to produce a porous material. A method for producing a sintered aluminum porous material, characterized in that an oxidized component of (i) is released in advance by heat treatment and / or vacuum treatment. 2. The heat treatment and / or the vacuum treatment are performed at a temperature of 100 to 600 ° C. for 2 to 30 hours and / or at a reduced pressure of 10 ° C.
^The method for producing an aluminum sintered porous material according to claim 1, wherein the Torr temperature is 100 to 600 ° C for 2 to 10 hours.