JP7037848B1 - Method for manufacturing high metal powder-containing aluminum complex, method for producing preform, and method for producing high metal powder-containing aluminum complex - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a manufacturing technique capable of increasing the filling rate of a metal powder and obtaining a uniform preform without internal defects, and when the preform is impregnated with an Al alloy or the like under high pressure or non-pressurized. Providing technology to obtain a high metal powder-containing aluminum composite with a high metal content with few cracks and defects. SOLUTION: In the process of producing a preform, two or more kinds of materials having different particle diameters are selected from metal powder materials having an average particle diameter of 1 to 200 μm, and an organic-inorganic binder is added and mixed with these metal raw materials. The molded product obtained from the material is fired at a temperature of 300 to 800 ° C. to obtain a preform having a metal raw material content of 55 v% or more, and the obtained preform is impregnated with a molten metal such as an aluminum alloy at high pressure. A method for producing an aluminum composite containing a high metal powder. [Selection diagram] None

Description

The present invention relates to a method for producing an aluminum composite containing a high metal powder, a method for producing a preform, and an aluminum composite containing a high metal powder. The present invention relates to a new technique capable of providing a high metal powder-containing aluminum composite which is well impregnated with the metal, and can bring about a dramatic improvement in the productivity and quality of the composite material.

In recent years, a material in which a metal and an Al alloy are composited has been used as a material having a light weight, high strength, high Young's modulus, high thermal conductivity, and low thermal expansion, for example, an electronic material such as a heat sink, a heat dissipation spreader, an electronic component package product, or an electronic material. , XY sliders, vacuum chucks and other semiconductor device members are attracting attention. These materials are a kind of so-called MMC (Metal Matrix Company). In the past, MMC in which ceramic powder was compounded with a metal matrix was common, but in recent years, composite materials composed of metal powder and Al alloys have been attracting attention. For example, it has been proposed to combine a composite material such as silicon and an Al alloy having a high Young's modulus and low thermal expansion, or a composite material such as an Al alloy with high-strength titanium or iron powder. Further, as described below, a composite of a metal powder and an Al alloy or the like is attracting attention because of its excellent processability.

For example, since silicon metal has a small coefficient of thermal expansion, it is used as an electronic component or a semiconductor component, but in addition to being extremely brittle, it has a weakness that it cannot manufacture complicated and large components. Therefore, a silicon aluminum composite with an Al alloy or the like is being developed. For the above reasons, firstly, a complex with aluminum containing as much silicon powder as possible is desired, and a complex having a small coefficient of thermal expansion and a large Young's modulus while maintaining processability is required. ing. Specifically, for example, if a silicon aluminum composite having a silicon component of 70 v% or more, preferably about 80 v%, can be produced, its application to heat sinks and electronic component packages for mounting electronic components having a small coefficient of thermal expansion will be dramatic. It is expected to spread to.

Titanium metal has a small coefficient of thermal expansion and is used as a wide variety of mechanical parts as a lightweight and highly rigid metal. However, it has a high hardness and is a difficult-to-process material, and in this respect, its use is limited. Therefore, if it is possible to combine an aluminum metal with a titanium metal to improve workability, the range of applications can be further expanded, and the development of a titanium aluminum composite is being requested and advanced.

Here, as a method for producing a composite of a metal powder and an Al alloy or the like, the method exemplified below is generally used.
(Casting method of high silicon aluminum alloy)
This method is a method of melting a silicon-containing aluminum alloy (also called a silicon-aluminum alloy) powder containing a silicon component, commonly called silumin, and casting it into a sand mold or a mold. However, in this method, when the silicon component becomes high, the alloy flowability deteriorates and casting becomes impossible. Therefore, the content of the silicon component is generally about 20 v% at the maximum. Therefore, it is difficult to produce a high-silicon aluminum composite having a high content of metal components as requested by the above-mentioned casting method.

(Spray forming method)
This method is a method in which silicon and aluminum are melted at a high temperature, a burette of a powder deposit obtained by spraying the melt is produced, and a silicon aluminum composite is produced by hot extrusion. It is called "the law". In the spray forming method, the metal can be melted at a high temperature to prepare a composite raw material powder in which the ratio of silicon and aluminum is freely changed. Therefore, it is theoretically possible to produce a high silicon-containing aluminum complex having a high content ratio of metal components. However, in order to produce a composite material having a silicon content of 50 v% or more, it is necessary to melt the material at 1000 ° C. or higher. In addition, since silicon is deposited first in the spray cooling process and a uniform composite cannot be obtained, only silicon components of about 50 v% are commercialized, and the silicon components are commercialized. It has not been possible to obtain a silicon aluminum complex having a higher content ratio of. In addition, since voids are generated in the solidification and deposition process of spraying the melt to produce a burette of powder deposits, in order to make a product, the obtained burette is semi-melted and extruded at high pressure, or HIP. Needs to be treated and crushed. In this respect, the "spray forming method" has a serious industrial problem that the manufacturing cost is very high and the economy is inferior.

(Non-pressurized permeation method of aluminum into silicon powder filler)
In Patent Document 1, a molten aluminum or an aluminum alloy is added to a filler or a molded body having a filling rate of silicon powder of 50 to 70% by volume under a temperature of 700 ° C. to 1000 ° C. in a nitrogen atmosphere containing magnesium vapor. A silicon-aluminum composite metal that has been infiltrated without pressure has been proposed. Patent Document 1 discloses that by including magnesium vapor in a nitrogen atmosphere, the molten Al alloy can be quickly permeated into the filler. Further, in the embodiment, a filler in which a container is filled with a mixture of 100 parts by mass of silicon powder having an average particle size of 5 μm and 2 parts by mass of magnesium powder is used, and the filling rate of silicon is 50% by volume. It is stated that. It is described that, if necessary, a silicon powder having an average particle size of 1 to 100 μm is used for the above embodiment.

As described above, what is disclosed in Patent Document 1 is that magnesium powder is added to one kind of silicon powder, which is filled in a container, and the packed material is charged with a normal pressure nitrogen atmosphere (non-pressurized). ) Is infiltrated with the molten Al alloy to produce a composite metal. However, according to the studies by the present inventors, a simple filler of silicon powder may be non-uniform or may have pores remaining inside. When such a filler is impregnated with a molten aluminum solution without pressure, there are problems that cracks and defects occur and that a filler in which the silicon powder is sufficiently filled in a uniform state cannot be obtained. be. Therefore, the non-pressurized permeation method using the filler described above cannot produce a uniform metal powder-aluminum complex having a high content ratio of metal components as required for products.

Further, in Patent Document 2, a metal such as molten aluminum is not pressurized to a molded or calcined metal powder obtained by adding PVA (polyvinyl alcohol) as a binder to a metal powder such as silicon powder. It is stated that it penetrates in. In the example, a material obtained by adding PVA as a binder to silicon powder having an average particle size of 20 μm was used, and a molten Al alloy was subjected to normal pressure in a nitrogen atmosphere furnace in which magnesium was present in a molded product obtained by press molding. It describes obtaining a composite metal by impregnation, using two types of metal powder, and mixing ceramic powder with metal powder. However, as can be seen from the fact that the ceramic powder is mixed with the metal powder, the technique described in Patent Document 2 is a molded body of the metal powder, which is a partner for non-pressurizing and infiltrating the molten metal to form a composite. Or, it is not a technique aimed at making the calcined body have a high metal content.

According to the studies by the present inventors, for example, when an aluminum alloy or the like is impregnated with high pressure or non-pressurized in a filler filled with silicon powder at a high content, the filler and the Al alloy or the like are impregnated in the impregnation process. Stress may be generated on the contact surface with the metal powder, and cracks or the like may be generated in the metal powder molded body when impregnated with the molten metal such as Al alloy, or the capillarity may be impaired by the cracks and unimpregnated defects may occur. On the other hand, in all of the above-mentioned conventional techniques, even if a study is made on how to obtain a high metal powder-aluminum complex having a high metal content with extremely few cracks and defects, such a complex is used. It is not the one that provided. For example, as in the above-mentioned conventional technique, even when aluminum metal is impregnated into a silicon powder filler or a compact that has just been press-molded without pressure, the contact surface between the silicon powder filler and an Al alloy or the like. Stress may be generated in the silicon, and cracks or the like may be generated when impregnated with the molten metal such as Al alloy, or unimpregnated defects may be generated.

Here, the merit of impregnating the packed material or the molded body with a molten metal such as an Al alloy by non-pressurizing permeation, which is performed in the above-mentioned conventional technique, is a molded body obtained by press-molding a metal powder (a molded body). A molten metal such as an Al alloy is gently impregnated into the molded body by a capillary phenomenon while maintaining the shape of the preform), and after impregnation, a metal powder-aluminum composite having a shape close to the product shape can be produced. That is, if a complex having a shape close to the product shape can be obtained after impregnating the molded body with the molten metal, the machining required after that can be reduced, which has an advantage of reducing the manufacturing cost.

This means that if a strong molded body (preform) that does not generate cracks or defects can be obtained when molten metal such as Al alloy is infiltrated without pressure, the product value and cost merit will increase dramatically. Means. Further, if the content of the metal powder material such as silicon of the obtained metal powder-aluminum composite can be increased, a metal powder-aluminum composite having a lower thermal expansion and a higher Young's modulus can be obtained. For example, if a method for producing a silicon powder-aluminum complex containing more than 50 v% of silicon can be established, its use will be significantly increased.

On the other hand, it is widely practiced to sinter a molded metal powder having a fine particle size at a temperature slightly lower than the melting temperature of the metal to produce a preform by a tentative sintering method of the powder. However, according to the studies by the present inventors, in this method, a molded body (preform) is produced by sintering, but during sintering, the molded body shrinks and the preform is deformed or the preform is formed. The voids inside become closed pores that are shielded from the outside, and in the subsequent impregnation step of Al alloy or the like, good impregnation may not be performed, and there is a possibility that a non-uniform metal powder aluminum composite is formed.

Japanese Unexamined Patent Publication No. 2005-036253 Japanese Unexamined Patent Publication No. 2004-052011

Therefore, an object of the present invention is to prepare a strong molded body (preform) of a metal powder represented by powders such as silicon, silicon-aluminum alloy, iron, titanium, copper, nickel, and ferrosilicon, and to produce a target performance. The filling rate of the metal powder can be increased according to the above, and the technology for producing a uniform preform with extremely few internal defects has been established, and aluminum or an aluminum alloy (Al alloy, etc.) is added to the obtained preform. A method for producing an aluminum composite containing a high metal powder, a high metal content, a high metal content, and a high amount obtained by the production method, both in the case of high-pressure impregnation and in the case of non-pressurized permeation. It is an object of the present invention to provide an aluminum composite containing a metal powder.

The above object is achieved by the following techniques for producing a high metal powder-containing aluminum complex having a high metal content. That is, the present invention provides the following method for producing a high metal powder-containing aluminum complex.
As the first invention, the following production method for obtaining a high metal powder-containing aluminum complex by impregnating with an Al alloy or the like under high pressure is provided.
[1] A preform manufacturing step for obtaining a metal powder molded body (preform) having a high metal content, and an impregnation step of aluminum or the like impregnating or impregnating the obtained preform with molten aluminum or an aluminum alloy. It is a method for producing an aluminum composite containing a high metal powder having a high metal powder.
In the process of producing the preform, two or more kinds of metal powder materials having different average particle diameters are selected from the metal powder materials having an average particle diameter of 1 μm or more and 200 μm or less and used as the metal raw material for the preform, and the metal raw material is used. The metal raw material content (volume ratio) is formed by using a mixture obtained by adding and mixing an organic-inorganic binder to the metal, and firing the obtained molded product at a temperature of 300 ° C. or higher and 800 ° C. or lower. Obtained a metal powder molded body having a value of 55 v% or more.
In the step of impregnating aluminum or the like, the metal powder molded body obtained in the step of producing the preform is impregnated with a molten metal of aluminum or an aluminum alloy at a high pressure of 10 MPa to 200 MPa. How to make a body.

As a second invention, the following production method for obtaining a high metal powder-containing aluminum complex by infiltrating an Al alloy or the like without pressure is provided.
[2] A preform manufacturing step for obtaining a metal powder molded body (preform) having a high metal content, and an impregnation step of aluminum or the like impregnating or impregnating the obtained preform with molten aluminum or an aluminum alloy. It is a method for producing an aluminum composite containing a high metal powder having a high metal powder.
Average particles from metal powder materials having an average particle diameter of 1 μm or more and ₂₀₀ μm or less (excluding Mg powder, AlMg powder, ZnMg powder, ZnAl powder, and Mg2Si powder) in the preform manufacturing process. Two or more kinds of metal powder materials having different diameters are selected as a metal raw material for preform, and 100 parts by mass of the metal raw material is composed of Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg _2Si powder. One or more powders selected from the group were added in an amount in the range of 0.2 to 5 parts by mass, and an organic-inorganic binder was added and mixed, and the mixture was molded and obtained. The molded product was fired at a temperature of 500 ° C. or lower to obtain a metal powder molded product having a metal raw material content (volume ratio) of 55 v% or more.
A method for producing a high metal powder-containing aluminum composite, which comprises infiltrating an aluminum or an aluminum alloy into a metal powder molded body obtained in the preform manufacturing step in the step of impregnating aluminum or the like without pressure. ..

Preferred forms of the above-mentioned method for producing a high metal powder-containing aluminum complex of the present invention include the following.
[3] The metal powder is selected from silicon powder or silicon alloy powder containing silicon, titanium powder, iron powder or iron alloy powder containing iron, and nickel powder or nickel alloy powder containing nickel [1]. Alternatively, the method for producing an aluminum composite containing a high metal powder according to [2].
[4] The high metal powder-containing aluminum composite according to any one of the above [1] to [3], wherein the volume content of the metal powder of the high metal powder-containing aluminum composite is 55 v% or more and 85 v% or less. Production method.
[5] The two or more kinds of metal powders having different average particle diameters include at least a metal powder A having an average particle diameter of 10 μm or less and a metal powder B having an average particle diameter of 40 μm or more. The production of the high metal powder-containing aluminum composite according to any one of the above [1] to [4], wherein the total amount of the metal powder contains at least 3% and the metal powder B contains 50% or more on a mass basis. Method.
[6] The high metal powder-containing aluminum composite according to any one of the above [1] to [5], wherein the organic-inorganic binder is at least one selected from the group consisting of silicone resin, Si alkoxide and Al alkoxide. Production method.

Further, as another embodiment, the present invention provides the following method for producing a preform, which is suitably used for the method for producing a high metal powder-containing aluminum complex of the first invention.
[7] Preform for obtaining a metal powder molded body (preform) having a high metal powder content, which is used when impregnating molten aluminum or an aluminum alloy at high pressure to obtain a high metal powder-containing aluminum composite metal. It is a manufacturing method of
A metal powder material having an average particle diameter of 1 μm or more and 200 μm or less contains at least a metal powder A having an average particle diameter of 10 μm or less and a metal powder B having an average particle diameter of 40 μm or more. Two or more kinds of metal powder materials having at least 3% in the total amount of the metal powder and containing 50% or more of the metal powder B and having different average particle diameters are selected as metal raw materials for preform. A mixture obtained by adding and mixing an organic-inorganic binder to a metal raw material is used for molding, and the obtained molded product is fired at a temperature of 300 ° C. or higher and 800 ° C. or lower to increase the content (volume) of the metal raw material. A method for producing a preform, which comprises obtaining a metal powder molded body having a rate) of 55 v% or more.

Further, as another embodiment, the present invention provides the following method for producing a preform, which is suitably used for the method for producing a high metal powder-containing aluminum complex of the second invention.
[8] To obtain a metal powder molded body (preform) having a high metal powder content, which is used when permeating molten aluminum or an aluminum alloy without pressure to obtain a high metal powder-containing aluminum composite metal. It ’s a method of making preforms.
From metal powder materials with an average particle size of 1 μm or more and 200 μm or less (excluding _each powder material of Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg2Si powder), at least a metal having an average particle size of 10 μm or less. A powder A and a metal powder B having an average particle diameter of 40 μm or more are contained, and the metal powder A is contained at least 3% in the total amount of the metal powder on a mass basis, and the metal powder B is contained in an amount of 50% or more. Two or more kinds of metal powder materials having different average particle diameters are selected as metal raw materials for preform, and Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg _2Si powder are used for 100 parts by mass of the metal raw material. One or more powders selected from the group consisting of two or more powders are added in an amount in the range of 0.2 to 5 parts by mass, and further, an organic-inorganic binder is added and mixed, and the mixture is molded and obtained. A method for producing a preform, which comprises firing the obtained molded product at a temperature of 500 ° C. or lower to obtain a metal powder molded product having a metal raw material content (volume ratio) of 55 v% or more.

Further, as another embodiment, the present invention provides the following high metal powder-containing aluminum complex.
[9] A high metal powder-containing aluminum composite having extremely few internal defects such as cavities, and the high metal powder using high-pressure impregnation according to any one of the above [1] and [3] to [6]. A high metal powder-containing aluminum composite obtained by a method for producing a containing aluminum composite.
[10] A near-net high metal powder-containing aluminum composite having a shape similar to that of a product, and the high metal powder-containing aluminum composite according to any one of [2] to [6] above, which utilizes non-pressurized permeation. A high metal powder-containing aluminum composite obtained by the production method of.

According to the present invention, for example, in the production of a molded body (preform) of a metal powder represented by powders such as silicon, silicon-aluminum alloy, iron, titanium, copper, nickel and ferrosilicon, a metal is produced according to a target performance. The volume filling rate of the powder can be increased to 55v% or more, and the obtained preform can be made uniform with extremely few internal defects. As a result, Al can be added to the preform. High-quality, high-metal powder-containing aluminum composite with high metal volume content, reduced occurrence of cracks and defects, both when alloys and the like are impregnated under high pressure and when infiltrated without pressure. Provided is an excellent method for producing an aluminum composite containing a high metal powder. Further, according to the present invention, there is provided a high-quality, high-metal powder-containing aluminum composite having extremely few internal defects such as cavities. These composites can be used as vacuum components in, for example, semiconductors, liquid crystal manufacturing equipment, electron microscopes, optical communication packages, and the like. Further, according to the present invention, since it is possible to produce a near-net high metal powder-containing aluminum composite having a shape similar to that of a product, the machining step required thereafter and the cost required for the step are reduced, and the composite is further formed. Since it is possible to increase the size of the robot arm, it is expected to be used as a large structural component such as a robot arm, a shape measuring device mount, and an XY table.

It is a schematic diagram for demonstrating the pressure permeation method which presses and permeates a molten metal such as an Al alloy into a preform, which is used in the manufacturing method of the high metal powder-containing aluminum composite of this invention. It is a schematic diagram for demonstrating how the molten metal such as Al alloy permeates into a preform by a capillary phenomenon and impregnates by the non-pressurizing permeation method performed by the method for producing a high metal powder-containing aluminum composite of this invention.

Hereinafter, the present invention will be described with reference to preferred embodiments, but the present invention is not limited to these embodiments.

[Making a metal powder molded body (preform)]
In view of the above-mentioned prior art, the present inventors have earnestly devised a method for producing a high metal powder-containing aluminum composite that has a high metal volume content, has few internal defects, and is expected to be used in various applications. As a result of the examination, it was concluded that it is important to establish a method that can easily produce a metal powder molded body (preform) having a high metal volume content and few voids inside. .. First, in order to obtain a metal preform having few voids that causes defects in the finally obtained composite material, the present inventors use metal powders having the same particle size as the material. Instead, it has been found that it is effective to prepare metal powders having different average particle sizes by using a material obtained by mixing two or more kinds of metal powders. That is, it was found that with such a configuration, fine particles having a small average particle diameter are inserted between the particles having a large average particle diameter, and as a result, the effect of the present invention can be obtained. In the present invention, two or more kinds of metal powders having different average particle diameters are selected, and a mixture obtained by mixing these is used as a metal raw material for preform.

(Metal powder material)
In the present invention, as the metal powder material for producing the preform, a material having an average particle diameter in the range of 1 μm or more and 200 μm or less is used. A metal powder in the range of 3 μm or more and 180 μm or less, more preferably 3 μm or more and 100 μm or less is used. The preform constituting the present invention is produced as a mixture obtained by selecting and mixing two or more kinds of metal powders having different average particle diameters from among the metal powders having an average particle diameter within such a range. It takes that. If only a material having an average particle diameter of less than 1 μm is used, the particles are too fine and the surface oxidation phase of the metal powder increases, which may deteriorate the performance of the metal powder. On the other hand, if the metal powder used is only 200 μm or more, the particle size is too large, and the particle filling property for performing press molding, CIP molding, sedimentation molding, etc. is deteriorated, which is not preferable.

In the present invention, when two or more kinds of metal powder materials having different average particle diameters for producing a preform are selected, a mixture composed of a combination of a metal powder having a large particle diameter and a metal powder having a small particle diameter is prepared. It is preferable to use it. For example, at least a metal powder A having an average particle diameter of 10 μm or less and a metal powder B having an average particle diameter of 40 μm or more are contained, and the metal powder A is contained at least 3% in the total amount of the metal powder on a mass basis. Moreover, it is preferable that the metal powder B is contained in an amount of 50% or more.

For example, when silicon powders of 45 μm and 5 μm having different average particle diameters are individually press-molded, their volume filling factors (v%: Vf) are 47% and 52%, respectively. According to the study by the present inventors, each silicon powder of 45 μm and 5 μm is mixed at a ratio of 70:30 on a mass basis, and press molding or the like using the mixture is finally performed to obtain Vf. = 73v% of molded product can be obtained. Similarly, 70 μm, 25 μm, and 5 μm silicon powders are mixed at a ratio of 70:25: 5 on a mass basis and press-molded using the mixture to obtain Vf = 78v% (volume%). Silicon molded body can be obtained.

Since the filling rate of metal powder such as silicon powder changes depending on the average particle size, particle shape, particle size distribution, etc., as a method of obtaining a desired high volume filling rate (v%), for example, it is placed in a carbon vessel or the like as much as possible. There is also a method of carefully applying vibration to obtain a high filling rate so that the filling is packed so as to have as few voids as possible. However, according to the study by the present inventors, it is not easy to obtain a filler having a metal powder raw material content of 55 v% or more by the method utilizing this vibration, and even if it is obtained, it is subsequently obtained. It was found that when the filler was impregnated with a molten metal such as Al alloy under high pressure, cracks and streaky defects occurred, and it was not possible to obtain a high-quality aluminum powder-containing aluminum composite. rice field.

As a result of diligent studies based on the above findings, the present inventors have used two or more kinds of metal powder materials having different average particle diameters, and used two or more kinds of mixed powders to form a mixed powder, such as press molding, CIP molding, and sedimentation method. By adopting and molding so that the metal powder is packed as tightly as possible, the content of the metal raw material is 55v% or more, and the filling rate is higher, and it can withstand high pressure impregnation with molten metal such as Al alloy. We have found that it is possible to produce a strong preform. Further, in order to further increase the strength of the preform, an organic-inorganic binder is added and mixed with the mixture of metal powders configured as described above, and a molded product composed of the obtained mixture is calcined at a temperature of 300 ° C. or higher and 800 ° C. or lower. I found it effective to do. These points will be described later.

In addition, the present inventors have diligently studied the preparation of a preform having a metal powder raw material content of 55 v% or more, which can be infiltrated with a molten metal such as an Al alloy without pressure. As a result, on a mass basis, for 100 parts by mass of the metal powder material, magnesium alloys such as metal Mg powder, Al—Mg alloy powder, Zn—Mg alloy powder and Zn—Al alloy powder, and magnesium. One or more powders selected from compounds such as Mg ₂ Si powder having a high content of Mg 2 (these are also referred to as metal powders containing Mg component, and may be described as Mg component) are 0.2 to 5 By using a mixture to which parts by mass are added, an organic-inorganic binder peculiar to the mixture is added, and a preform obtained by firing a molded product composed of these mixtures at a temperature of 500 ° C. or lower is used, an Al alloy or the like can be used. It was found that the molten metal of No. 1 can be infiltrated into a good state without pressurization, and a high-quality high-metal powder-containing aluminum composite can be obtained. That is, for example, the Mg component present in the preform produces Mg ₃ N ₂ in the nitrogen atmosphere during non-pressurized permeation, which will be described later, and the metal oxide on the surface of the metal powder is made of Mg. It is reduced and metallized by the thermite reaction to improve the wettability between the metal powder and the molten metal such as Al alloy. According to the present invention, it is considered that the action of these Mg components makes it possible to infiltrate the molten metal such as Al alloy into the produced preform in a good state without pressure.

As the Mg component-containing metal powder and the like mentioned above, it is preferable to use a powder having an average particle diameter of 0.5 μm or more and 150 μm or less. A powder having a size of more than 150 μm is not preferable because it may be too coarse to be uniformly mixed with the metal powder material described above. Further, when the particle size is coarse, the surface area of the Mg component becomes small, and the amount of Mg ₃ N ₂ produced after the Mg contained in the preform reacts with nitrogen in the atmosphere and is nitrided becomes small. Here, if the amount of Mg ₃ N ₂ produced is small, the permeation rate of the Al alloy or the like into the preform becomes slow, which is not preferable. On the other hand, the finer the Mg component, the larger the surface area, and it becomes easier to be oxidized by oxygen in the air to become MgO, which is not preferable because the amount of Mg decreases. Therefore, it is desirable to use a metal powder containing a Mg component having an average particle diameter of 0.5 μm or more. Further, when the average particle diameter exceeds 150 μm, the total surface area becomes small, and as described above, the amount of Mg ₃ N ₂ produced is small, which is not preferable.

The amount of the metal powder containing the Mg component added and mixed is within the range of 0.2 to 5 parts by mass in terms of Mg with respect to 100 parts by mass of the metal powder on a mass basis. More preferably, it is used within the range of 0.5 to 5 parts by mass. If the amount of the metal powder containing the Mg component is as small as less than 0.2 parts by mass, the amount of Mg ₃ N ₂ produced is small and the permeation rate of the molten metal such as Al alloy is not sufficiently promoted, which is not preferable. On the other hand, when the amount of the Mg component-containing metal powder or the like is more than 5 parts by mass, the distribution state of the Mg component in the preforms produced from these raw materials is locally increased, and Al permeated due to this. It is not preferable because the amount of alloy or the like may be non-uniform. When the above-mentioned Mg-based alloys or Mg-containing compounds are used, the mixing amount may be determined by converting them into Mg contained therein.

The metal powder used in the present invention is not particularly limited, and is, for example, a metal typified by silicon powder, silicon aluminum alloy powder, ferrosilicon alloy powder, iron or iron-based powder, titanium powder, nickel or nickel-based powder, and the like. Examples include powder. As described above, in order to impregnate the preform with a molten metal such as an Al alloy in a good state without pressurization, it is preferable to allow the Mg component to be present in the preform. .. Therefore, in addition to the metal powders listed above, the mixture for producing the preform used for non-pressurized permeation contains one or more kinds of Mg component-containing metal powders and the like in the range of 0.2 to 5 parts by mass. It is necessary to add in the amount of the above, and further, the molded product is fired at a temperature of 500 ° C. or lower. Therefore, when producing a preform to be used for non-pressurized permeation, it is necessary not to use any of two or more kinds of metal powder materials having different average particle diameters, such as a metal powder containing Mg component. ..

On the other hand, when the preform is used for high-pressure impregnation, a metal powder containing Mg component or the like is used as two or more kinds of metal powder materials having different average particle diameters in producing the preform. There is no problem even if it is used. In this case, the molded product obtained by molding the mixture is fired at a temperature of 300 ° C. or higher and 800 ° C. or lower to prepare a preform. Among them, for example, Mg is oxidized to MgO, and the Mg component which is important for non-pressurized permeation does not exist in the preform. Further, at a temperature exceeding 800 ° C., the metal powder may be oxidized and the original properties of the metal may be impaired.

(Organic inorganic binder)
Since the molten metal of Al alloy or the like is impregnated into the preform at high pressure or permeated without pressure, the preform to be used must have strength to withstand the stress generated by the impregnation and permeation of the molten metal such as Al alloy. Is. In the first aspect of the present invention, it is necessary to impregnate a molten metal such as an Al alloy with high pressure, and specifically, the molten Al alloy or the like is impregnated at several tens of MPa. Needs higher strength to withstand high pressure. Further, even when the molten Al alloy or the like is permeated into the preform of the second invention of the present invention by non-pressurization permeation, stress is generated on the surface where the molten metal of the Al alloy or the like comes into contact with the preform. According to the study by the present inventors, when a molten metal such as an Al alloy is infiltrated into the packed phase of a metal powder simply filled by a method such as vibration at high pressure or without pressure, cracks and defects occur. Sometimes. Therefore, regardless of the method of impregnating / infiltrating the molten metal such as Al alloy, it is desired to prepare a stronger preform and to impregnate the preform with Al alloy or the like.

Usually, in order to prepare a high-strength preform from ceramic powder or the like and obtain a composite such as a cellamics-Al alloy, an inorganic binder such as colloidal silica is added and mixed with the cellamics and molded, and the obtained molding is performed. It is necessary to bake the body at a temperature of about 1000 ° C. or higher to prepare a preform. However, the complex of the present invention is a complex of a metal powder and an Al alloy or the like, and the above-mentioned conventional technique cannot be used. That is, when a molded product obtained by adding and mixing an inorganic binder to a metal powder and mixing it for the purpose of obtaining a high-strength preform is fired at a temperature of 1000 ° C., the metal powder is oxidized and the performance as a metal is impaired. The conventional method could not be adopted. On the other hand, in the present invention, as specified in the present invention, by adding and mixing an organic-inorganic binder to a metal powder to obtain a molded product, it is possible to obtain a compact by firing in a low temperature range of 300 ° C to 800 ° C. , It has become possible to prepare a preform containing a metal powder with a high content, and as a result, a remarkable effect of the present invention has been obtained.

As a result of diligent development in response to the above request, it is more possible to use a mixture obtained by adding and mixing an organic-inorganic binder to two or more kinds of metal powder materials having different average particle sizes as described above. It has been found to be effective as a means to obtain a strong preform. The background will be explained.

In order to strengthen the preform, the metal powder should be packed as closely as possible and formed by applying pressure by the press, CIP, sedimentation method, etc. described above, and a binder should be added to the metal mixed powder as the raw material. desired. Generally, as a binder used for molding ceramics and the like, organic substances typified by polyvinyl alcohol (PVA) and polyvinyl butyral (PVB) are used. However, if the preform produced by using these organic binders is impregnated with a molten Al alloy or the like at high pressure or permeated without pressure, gas may be generated and the impregnation of the Al alloy or the like may be hindered. In order to prevent this problem, the preform must be fired in advance to remove organic substances that are gas generation sources. This means that organic binders such as PVA and PVB cannot be used because they cannot function as a binder for strengthening the preform after firing. On the other hand, it is conceivable to add an inorganic binder such as colloidal silica or colloidal alumina to the metal powder material, mold it with a press, CIP or the like, and then calcin it to strengthen the preform. Then, in order to obtain a preform exhibiting strength with these inorganic binders, it is necessary to bake the preform at 1000 ° C. or higher. However, when fired at this temperature, the metal powder, which is the main raw material, is oxidized and its function as a metal is impaired. Therefore, general inorganic binders such as colloidal silica and colloidal alumina cannot be used.

In contrast to the above, as a result of diligent studies, the present inventors formed a mixture of two or more kinds of metal powder materials with an organic-inorganic binder added and mixed, and the obtained molded product was a molten Al alloy or the like. By firing at a specific temperature according to the impregnation method to prepare a preform, impregnation of molten metal such as Al alloy with or without pressurization can be realized in good condition. I found that I could get a good preform.

The organic-inorganic binder used in the present invention includes a silicone resin, a silicon organic derivative such as Si alkidine having a chemical structure of Si—OR (R: organic substance), or Al—OR (R: organic substance). Aluminum organic derivatives such as aluminum alkoxide having the above chemical structure can be used. According to the studies by the present inventors, first, by using a mixture of metal powders to which an organic-inorganic compound as described above is added as a binder, a strong molded product at room temperature can be produced. Then, according to the study by the present inventors, the obtained molded product is then fired at a temperature of 800 ° C. or lower, 300 ° C. or higher and 800 ° C. or lower, in which the metal powder is not oxidized, to prepare a preform. It was found that a strong metal powder molded product (preform) can be obtained after firing even though the organic matter in the molded product is removed by firing. The present inventors consider the reason why such an effect is obtained as follows. First, when an organic-inorganic compound as described above is added to a metal powder and molded, it exhibits strength as a so-called adhesive at room temperature, similar to a general organic binder. Further, when heated at 300 ° C. or higher, the organic matter of the organic-inorganic compound is burnt off, but the inorganic matter in the structure of the organic-inorganic compound acts as an inorganic binder and strengthens the preform obtained after firing. The effects obtained by using the organic / inorganic binder will be described in more detail below.

As described above, general inorganic binders such as colloidal silica and colloidal alumina cannot contribute to the development of preform strength unless they are calcined at a temperature of 1000 ° C. or higher. On the other hand, in the organic-inorganic binder used in the present invention, when fired, the organic matter is fired and removed at a firing temperature of 300 ° C. or higher, and the SiO ₂ component and Al ₂ O ₃ component remaining after firing are amorphous (amorphous). ), Combined with the metal powder. Therefore, for example, the preform after firing even at a low temperature of about 300 ° C. exhibits strength. Further, according to the study by the present inventors, the metal powder is not oxidized even when fired at a high temperature of 800 ° C. or lower, so that a sufficiently strong preform can be produced. Further, since the organic / inorganic binder as described above decomposes and removes organic substances at a temperature of 300 ° C., it has an advantage that no organic gas is generated by the organic substances when impregnated with a molten metal such as an Al alloy. .. The reason why the above-mentioned effect is obtained is that the organic-inorganic binder used in the present invention, for example, Si-alkide, has a molecular structure of Si—OR (R: organic substance), and therefore is a general organic binder. Compared to the above, the organic matter is less likely to remain _carbonized even at a temperature of 300 to 800 ° C., and the organic matter is easily burned off. It seems that it has demonstrated its strength. Further, since the inorganic organic binder required to be used in the present invention can be used in an organic solvent such as ethanol, IPA, and toluene, there is an advantage that deterioration due to the reaction between the metal powder and water can be suppressed.

As described above, in both the first invention and the second invention of the present invention, organic substances are decomposed and removed at a relatively low temperature to obtain a strong preform. As described below, this is an important factor for the obtained preform to be impregnated with a molten metal such as an Al alloy in a good state under high pressure or non-pressurization. That is, in the case of high-pressure impregnation performed in the first aspect of the present invention, specifically, after preheating the preform at a temperature of 800 ° C. or lower, the preform is subjected to an Al alloy having a temperature of 700 ° C. to 800 ° C. or the like. The molten metal is impregnated with high pressure, and at that time, the preform can exhibit sufficient strength even against such a high temperature molten metal. Further, since there is no gas generated from the inside of the preform which is difficult to remove, the molten metal such as Al alloy can be impregnated to the inside.

On the other hand, in the case of the non-pressurized permeation performed in the second invention of the present invention, as described above, the Mg component-containing metal powder or the like is configured to be mixed in the preform in a predetermined amount. For example, if the component-containing metal powder or the like is a metal Mg powder or an Mg-containing alloy powder, it is oxidized to MgO at a temperature of more than 500 ° C., so it is necessary to bake the preform at a temperature of 500 ° C. or lower. According to the studies by the present inventors, in addition to firing the preform at a low temperature of 500 ° C. or lower, the organic-inorganic binder described above is desired when mixing the metal powder material to obtain a molded product. By adding an amount, the Mg component-containing metal powder or the like is not oxidized when the molded product is fired, and a strong preform that does not collapse when the molten metal such as Al alloy is permeated without pressure is produced. be able to.

When the organic-inorganic binder used in the present invention is in a solid state, it may be added by dissolving it in an organic solvent such as ethanol or IPA. In the case of a liquid, it can be added as it is or diluted with an organic solvent such as ethanol or IPA. An appropriate amount of an organic solvent such as ethanol or IPA may be added and mixed so that the metal powder raw material and the organic-inorganic binder can be easily mixed. The amount of the organic-inorganic binder used in the present invention is, for example, about 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the metal powder raw material in terms of SiO ₂ or Al ₂ O ₃ . It is preferable to add and mix in a range. If the addition amount is smaller than the above range, the desired preform strength may not be sufficiently obtained because the addition amount is too small. If the addition amount is larger than the above range, the finally obtained aluminum composite will have a large amount of inorganic substances such as SiO ₂ and Al ₂ O ₃ , and the metal content which is the object of the present invention is contained. It is not preferable because there is a concern that an aluminum composite containing a high metal powder having a high rate cannot be obtained, and the performance of the product is deteriorated.

(Preparation method of molded product)
In the present invention, two or more kinds of metal powder materials having different average particle sizes are selected as a metal raw material for preform, and a mixture obtained by adding and mixing an organic-inorganic binder as described above to the metal raw material. A molded product is obtained by molding using the above, and the obtained molded product is fired at a specific temperature to produce a high-strength preform. Specifically, a metal powder mixture obtained by mixing an organic-inorganic binder as described above with two or more kinds of metal powder materials having different average particle diameters is molded to obtain a molded product.

The molding method of the molded product is not particularly limited, and examples thereof include the following methods. A method of drying a metal powder mixture and performing dry molding such as press molding or CIP to obtain a molded body, or a method of making a metal powder mixture into a slurry using an organic solvent and vibrating sedimentation molding, or casting molding with a plaster mold. A method of obtaining a molded product and the like can be mentioned. When the metal powder mixture is made into a slurry, it is preferable to reduce the amount of water used to prepare the slurry with an organic solvent. This is because if there is a large amount of water, the metal powder reacts with water, and the metal powder may change to hydroxide or the like and deteriorate. For example, when the metal powder is silicon powder, the following reaction may proceed and the silicon may deteriorate.
Si + 4H ₂ O ⇒ Si (OH) ₄ + 2H ₂

Further, when the metal powder is titanium powder, the following reaction proceeds and titanium may be deteriorated. That is, titanium becomes an oxide in the reaction of Ti + 2H ₂ O → TIO ₂ + 2H ₂ . In the case of other metal powders, it also reacts with water to form an oxide, so it is basically not preferable to use water. To suppress this problem, an organic solvent such as alcohol is used, or a mixed solvent of water and a hydrophilic organic solvent such as alcohol is used. Also in this case, in order to suppress the above reaction, it is preferable to reduce the amount of water in the mixed solvent. According to the studies by the present inventors, if the water content is 30 parts by weight or less with respect to 100 parts by weight of the organic solvent, the above reaction does not occur.

When the metal powder mixture is dried and a molded product is obtained by press molding or dry molding such as CIP, the above-mentioned problems do not occur. By using press molding, which is widely used as a method for obtaining a molded product of a powder material, the desired molded product according to the present invention can be easily obtained. Further, since the density of the obtained molded product can be homogenized by using CIP molding, it is also preferable to obtain a molded product by using CIP molding. For example, it is also a preferable method to perform temporary molding by press molding and then CIP molding.

(Baking of molded product)
In the present invention, the molded product obtained as described above is fired (temporarily fired) to obtain a metal powder molded body (preform) having a high metal content. In that case, when the preform is impregnated with a molten metal such as Al alloy at a high pressure of 10 MPa to 200 MPa, it is fired at a temperature of 300 ° C. or higher and 800 ° C. or lower. When the molten metal such as Al alloy is infiltrated into the preform without pressurization, it is fired at a temperature of 500 ° C. or lower, for example, a temperature of 300 ° C. or higher and 500 ° C. or lower. First, by firing the molded product at the above-mentioned temperature, the organic matter derived from the organic-inorganic binder or the like contained in the molded product is removed. If the organic matter remains in the molded product, when the Al alloy or the like is infiltrated into the molded product, the hot water of the Al alloy or the like and the organic matter come into contact with each other to generate gas, and the permeation of the Al alloy or the like is hindered. Since it may occur, it is necessary to remove organic substances by firing.

Further, by firing the molded product at the above-mentioned temperature to prepare a preform, the preform, which is the original object of the present invention, is impregnated with a melted Al alloy or the like under either high pressure or non-pressurized conditions. Even in such a case, it becomes possible to give sufficient strength. Further, as described above, if the present invention can produce a near-net high metal powder-containing aluminum complex having a shape similar to that of a product, the processing cost can be significantly reduced, which is very useful. In order to achieve this purpose, it is necessary to make the preform strong enough to be machined before impregnating it with a melted Al alloy or the like. It is important to bake to make a preform.

The temperature conditions for obtaining a metal powder molded body (preform) having a high metal content are high-pressure impregnation or non-high-pressure impregnation as a method for impregnating the preform with a molten Al alloy or the like in the subsequent step. It depends on whether pressure penetration is performed. When a preform to be subjected to high-pressure impregnation is obtained, a molten metal such as an Al alloy is impregnated with a relatively large pressure of about 10 MPa to 100 MPa, so that the preform to be used needs to have a strength to withstand this. However, according to the study by the present inventors, if the firing temperature is too high, the metal powder that is the raw material of the preform is oxidized, so that it is necessary to fire at a temperature of 800 ° C. or lower in order to suppress the oxidation. Further, in order to sufficiently remove the organic matter derived from the organic-inorganic binder added to the metal powder, it is necessary to bake at a temperature of 300 ° C. or higher. According to the studies by the present inventors, when obtaining a preform to be subjected to high-pressure impregnation, it is preferable to bake at a temperature of more than 500 ° C. and 800 ° C. or lower. More preferably, it is preferable to bake at a temperature of 700 ° C. or higher and 800 ° C. or lower.

According to the study by the present inventors, when a preform to be subjected to non-pressurized permeation is obtained, stress is generated in a portion of the preform that is in contact with the molten metal such as an Al alloy due to the non-pressurized permeation. You need something with a preform strength that can withstand. Therefore, similar to the preform to be subjected to high-pressure impregnation, firing is performed to remove organic substances in the molded product and improve the obtained preform strength. However, in the case of non-pressurized permeation, as described above, in order to permeate the molten metal such as Al alloy in a good state without pressure, the preform to be permeated is the Mg metal described above. It is necessary that the Mg component-containing metal powder such as powder is added. On the other hand, for example, when the temperature of Mg metal powder exceeds 500 ° C., it reacts with oxygen in the air to become MgO, and the Mg component required for non-pressurized permeation becomes insufficient. Therefore, the firing temperature needs to be 500 ° C. or lower. According to the study by the present inventors, when subjected to non-pressurized permeation, a preform having a high metal content and which can sufficiently calcinate and remove organic substances by calcination at a temperature of 300 ° C. or higher and 450 ° C. or lower can be obtained. It will be possible to make it strong enough to withstand non-pressurized infiltration.

[Preparation of aluminum complex containing high metal powder]
Next, the step of impregnating aluminum or the like performed when obtaining the high metal powder-containing aluminum complex of the present invention will be described. In this step, the preform having a high metal content and excellent strength obtained by the configuration described above is impregnated or infiltrated with molten aluminum or an aluminum alloy (Al alloy or the like). Hereinafter, the method using high-pressure impregnation and the method using non-pressurized permeation will be described.

(High-pressure impregnation method of Al alloy etc. into preform)
FIG. 1 schematically shows a conceptual diagram of high-pressure impregnation. As shown in FIG. 1 (A), the preform having a high metal content is loaded into the frame of the press machine heated to 300 ° C. to 800 ° C. and preheated. The reason for loading the preform in a preheated state is that when the preform is impregnated with molten metal such as Al alloy under high pressure, if the temperature of the preform is low, the Al alloy etc. cools and solidifies during the high pressure impregnation and the preform is preformed. This is to prevent this because it may happen that the inside is not impregnated. Similarly, the frame type should be heated (preheated) to 200 to 400 ° C. with a burner or the like so that the Al alloy or the like does not cool and solidify during impregnation.

Al alloy or the like melted at 600 ° C to 800 ° C is poured into a container loaded with the preform as described above, and as shown in FIG. 1 (B), a load is applied with an upper punch and pressed, etc. The preform is impregnated with a molten metal such as an Al alloy. The press pressure is 10 Mpa to 200 Mpa. If it is less than 10 MPa, the pressure is too low and the preform may not be impregnated with the molten metal such as Al alloy, which is not preferable. Impregnation may be performed at a higher pressure of more than 200 Mpa, but the ability of the apparatus for obtaining the complex of the present invention is sufficient if a press pressure in the above range can be obtained. The press-impregnated body thus obtained is cooled to remove aluminum around the preform to obtain a high metal powder-containing aluminum composite intended by the present invention.

(Non-pressurized permeation method for Al alloy, etc. into preform)
FIG. 2 schematically shows a stepwise conceptual diagram of non-pressurized infiltration. First, a preform having a high metal content, which contains a metal powder containing an Mg component, such as a Mg metal powder, is loaded into an electric furnace capable of ensuring a nitrogen atmosphere as described below. At the bottom of the preform, preferably, a small piece of the same material as the preform is placed as an infiltration path. A solid Al alloy or the like to be infiltrated is installed in the vicinity so as not to come into contact with the preform. As shown in FIG. 2, the preform and the Al alloy or the like are installed in a carbon vessel or the like so as not to react with the members inside the electric furnace.

After arranging the preform and the solid Al alloy or the like as described above, the temperature is gradually raised while maintaining the nitrogen atmosphere inside the electric furnace, and the temperature is maintained at 700 to 900 ° C. for 2 hours to 5 hours. During this period, as shown stepwise in FIG. 2, the melted Al alloy or the like permeates the preform through the permeation path without pressure, and a high metal powder-containing aluminum complex is obtained.

Hereinafter, a case where the Mg component-containing metal powder or the like is Mg powder will be described as an example. The above-mentioned principle of non-pressurized permeation is that Mg reacts with nitrogen to generate Mg ₃ N ₂ and precipitates in the preform to improve wettability with Al alloys, etc., or Mg is thermite. It is considered that the reaction was caused and the surface oxide of the metal powder constituting the preform was reduced to improve the wettability between the metal powder and the Al alloy or the like. As described above, in the prior art, the molded product obtained by press molding or the like is used for non-pressurized permeation without firing, and when Al alloy or the like is non-pressurized permeated, Mg powder is used. A method is performed in which a molded product containing no metal is used and placed in a nitrogen atmosphere containing magnesium vapor to allow Al metal to permeate. However, according to the study by the present inventors, in this method, Mg ₃ N ₂ is generated on the surface of the preform by reacting with Mg vapor in the atmosphere with nitrogen, and Al alloy or the like is formed in this state. It takes a long time to impregnate the entire preform with aluminum because it will penetrate. Further, since Mg ₃ N ₂ is not uniformly generated on the surface of the preform, the Al alloy or the like may permeate unevenly, and the entire preform may not be uniformly impregnated.

According to the technique of the present invention, unlike the case of the above-mentioned conventional technique, Mg powder can be uniformly mixed in the preform, so that Mg ₃ N ₂ is generated in the entire preform, and thus impregnation with an Al alloy or the like. The speed is dramatically increased, and the entire preform can be uniformly impregnated. In addition, when non-pressurized permeation is used, Al alloy or the like can be permeated in the shape of the preform, so that a high metal powder-containing aluminum composite can be manufactured with a near net close to the product shape. There is a big merit that processing can be reduced.

Hereinafter, further specific examples of the above-mentioned embodiment will be described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the text, w% is based on mass, and v% is based on volume. The average particle size in the present specification is a value measured by a laser diffraction type particle size distribution measuring instrument.

[Example 1] (using the high pressure impregnation method)
First, a metal powder molded body (preform) having a high metal content was produced by the following procedure. In this example, in order to prepare a preform, three kinds of silicon powders having different average particle diameters were combined in the following composition and used by stirring and mixing. Specifically, 1820 g of silicon powder having an average particle diameter of 45 μm, 780 g of silicon powder having an average particle diameter of 25 μm, and 100 g of silicon powder having an average particle diameter of 5 μm are blended in a total of 2700 g, and the average particle diameters are mutual. A mixture of three different silicon powders was used. To this mixture, 130 g of ethyl silicate, which is an organic-inorganic binder containing 40 w% of silicon in terms of SiO ₂ , is added, and the mixture is further stirred and mixed with a stirrer for 15 minutes to obtain the mixed powder used in this example. I got a body.

The whole amount of the mixed powder obtained above was put into a press die having an inner size of 200 mm × 200 mm × 150 mm (depth), and press molding was performed at 300 kg / cm ² total pressure 120 t. Then, the obtained press-molded product was placed in an electric furnace, heated to 700 ° C. at a heating rate of 50 ° C./hr, held at this temperature for 3 hours, and then cooled to room temperature to be made of silicon metal. A preform was made. When the weight and external dimensions of this preform were measured and the bulk density was calculated, there was a silicon preform having a volume filling factor (Vf) of 77%.

The preform obtained above is preheated to 500 ° C. in an electric furnace, and the preheated preform is heated to 250 ° C. with a burner of a high-pressure impregnation press machine for high-pressure impregnation. Was loaded. An aluminum alloy (AC4C) melted at 750 ° C. is put into this die up to about 20 mm above the die, a press punch is pushed into the die from above, and held at a pressure of 100 Mpa for 10 minutes to obtain the first. The silicon preform was impregnated with molten aluminum under high pressure (see FIG. 1).

After cooling, the aluminum around the preform was processed and removed, and the product part of the silicon-aluminum complex was taken out. The product part was a silicon-aluminum complex (hereinafter, also referred to as a silicon-aluminum complex) uniformly impregnated with aluminum without small pores (castings) or cracks. When the bulk specific density was calculated from the weight measurement and the external dimension measurement, it was found that the silicon-aluminum composite was 78v% silicon and 22v% aluminum alloy.

[Example 2] (using the non-pressurized infiltration method)
A metal powder molded body (preform) having a high metal content used in this example was produced by the following procedure. 50 g of Mg powder having an average particle diameter of 80 μm was added to a total of 2700 g of three types of silicon powder having different average particle diameters, which were weighed so as to have the same composition as that used in Example 1. Further, 130 g of ethyl silicate was added to this mixture as in Example 1, and the mixture was mixed with a stirrer for 10 minutes.

The whole amount of the mixed powder obtained above was put into a press die having an inner size of 200 mm × 200 mm × 150 mm (depth), and press molding was performed at 150 kg / cm ² total pressure 60 t. This was removed from the mold, and the obtained pressed product was placed in a normal air atmosphere electric furnace, heated to 450 ° C. at a heating rate of 50 ° C./hr, held at this temperature for 3 hours, and then cooled. To make a preform. When the bulk density was calculated in the same manner as in Example 1, the volume filling factor (Vf) was 73%.

The preform obtained above was placed in a carbon vessel so as to have a "non-pressurized permeation principle diagram" schematically shown in FIG. Specifically, four permeation paths having a size of 30 mm × 30 mm × 30 mm prepared from the same material as the preform obtained above are placed under the preform in a grounded state, and further. Next to the preform, 2500 g of solid aluminum alloy (AC4A) was placed. Then, the entire carbon vessel on which the preform and the like were arranged as described above was placed in a nitrogen atmosphere furnace, heated at 50 ° C./hr, held at 800 ° C. for 5 hours, and then cooled.

After cooling, the permeation path was removed, and the surface and inside of the preform were processed and observed. As a result, it was confirmed that the preform was a silicon-aluminum complex completely impregnated with aluminum. From the weight of the obtained silicon-aluminum composite and the bulk specific gravity calculated from the measured values of the outer shape, the composite is a silicon-aluminum composite having 73v% silicon and 26v% aluminum alloy and having no pores or cracks. rice field.

[Example 3] (using the high pressure impregnation method)
A metal powder molded body (preform) having a high metal content used in this example was produced by the following procedure. 1820 g of silicon powder with an average particle size of 80 μm, 780 g of silicon powder with an average particle size of 25 μm, and 100 g of silicon powder with an average particle size of 3 μm, for a total of 2700 g, three types with different average particle sizes. A mixture of silicon powder was used. To this mixture, 180 g of an isopropyl alcohol solution in which a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KR-220L) is dissolved so as to be 30 w% is added, and the mixture is stirred with a stirrer for 15 minutes, and then the same as in Example 1. The whole amount was loaded into the press mold and press-molded under the same conditions as in Example 1. Then, the obtained press-molded product was placed in an electric furnace, heated to 750 ° C. at a heating rate of 70 ° C./hr, and fired at this temperature to obtain a preform having a volume filling rate of 78v%. The volume filling factor was obtained in the same manner as in Example 1.

The preform obtained above was impregnated with the melted aluminum alloy by a high-pressure impregnation press machine under the same conditions and procedures as in Example 1. After cooling, the surrounding aluminum was processed and removed, the product part was taken out, and its weight and external shape were measured to calculate the bulk specific density. As a result, it was confirmed that the obtained composite was a silicon-aluminum composite containing 78v% silicon and 22v% aluminum alloy and having no pores (cavities) or cracks.

[Example 4] (using the non-pressurized infiltration method)
A metal powder molded body (preform) having a high metal content used in this example was produced by the following procedure. A preform having a shape of 200 mm × 200 mm × 40 mm, which was produced by the same procedure as in Example 2 and containing Mg powder, was machined by a milling cutter, and the molded product was 75 mm × 75 mm. A ribbed preform was obtained in which four cavities of × 25 mm (depth) were evenly arranged. The obtained preform was a strong preform having machinable strength.

Using the preform obtained above, non-pressurized permeation of the aluminum alloy (AC4A) was performed from the permeation path under the preform arranged in the carbon vessel in the same manner as in Example 2. Then, as in Example 2, the permeation path was removed and the bulk specific density was measured. As a result, silicon was 73v%, aluminum alloy was 27v%, and there were no pores or cracks, and a silicon-aluminum composite was found. I confirmed that it was obtained. In addition, there was no exudation of aluminum alloy inside the cavity, and a silicon-aluminum composite could be manufactured with a near net in the shape of the preform.

[Example 5] (using the high pressure impregnation method)
A metal powder molded body (preform) having a high metal content used in this example was produced by the following procedure. To 1400 g of iron powder having an average particle size of 80 μm and 600 g of iron powder having an _average particle size of 10 μm, 80 g of ethyl silicate containing 40 w% of silicon (silicon) was added and stirred and mixed for 15 minutes. This mixed powder was placed in a press die having an inner size of 200 mm × 200 mm × 150 mm (depth), and press molding was performed at 150 kg / cm ² total pressure 60 t. Then, the press-molded product is placed in an electric furnace, heated to 700 ° C. at a heating rate of 50 ° C./hr, maintained at this temperature for 3 hours, and then cooled to room temperature to obtain an iron metal preform. Made. When the weight and external dimensions of the obtained preform were measured and the bulk density was calculated, there was an iron powder preform having a volume filling factor (Vf) of 73%.

The preform obtained above was preheated to 500 ° C. in an electric furnace and loaded into a die having a depth of 300 mmΦ × 250 mm heated to 250 ° C. with a burner of a high-pressure impregnation press machine in order to perform high-pressure impregnation. An aluminum alloy (AC4C) melted at 750 ° C. was placed in this die up to about 20 mm above the die, a press punch was pushed into the die from above, and the die was held at a pressure of 100 MPa for 10 minutes for high-pressure impregnation.

After cooling, the surrounding aluminum was processed and removed, and the product part of the iron-aluminum alloy composite (hereinafter, also referred to as iron-aluminum composite) was taken out. The product part was an iron-aluminum complex in which aluminum was uniformly impregnated into a preform made of iron powder without small pores (cavities) or cracks. When the bulk specific density was calculated from the weight measurement and the external dimension measurement, it was an iron-aluminum composite containing 73v% of iron and 27v% of aluminum alloy.

[Comparative Example 1] (No binder used, high pressure impregnation method used)
A silicon mixed powder having the same composition and weight as in Example 1 was placed in a 200 mm × 200 mm × 100 mm iron box as a powder without adding a binder such as a silicone resin or ethyl silicate, and the entire box was placed on a vibrator. Filling was performed by applying partial vibration. Then, the entire box was impregnated with aluminum under high pressure in the same manner as in Example 1, and after cooling, the complex was cut out.

When the processed surface of the cut-out complex was observed, many streaky aluminum defects were found. It is considered that this is because a crack was generated in the metal powder filler during the high pressure impregnation and the aluminum alloy invaded the crack. As a result of cutting out the crack-free portion and calculating the bulk specific gravity, the filling rate of silicon was 62v%, and the filling rate of silicon was lower than that of the preform of Example 1. The above result shows that the filling rate of silicon is low and the strength of the silicon packed phase is not sufficient just by filling the particles of silicon powder as they are, and the packed phase cracks during the high-pressure impregnation of the molten aluminum. , Indicates that a defect has occurred in which aluminum has invaded.

[Comparative Example 2] (Binder not used, preform produced by press molding)
A silicon mixed powder having the same composition and weight as in Example 1 was press-molded by the same procedure using the mixed powder without adding ethyl silicate. However, the obtained molded product had insufficient strength and collapsed when it was removed from the mold, and it was not possible to produce a preform that could be used for producing a complex. From the above results, it was found that the addition of a binder to the powder material is indispensable when press molding using the silicon mixed powder material.

[Comparative Example 3] (Binder-free, preform production by sedimentation molding)
Using a silicon mixed powder having the same composition and weight as in Example 3, a slurry was prepared without adding a binder such as a silicone resin or ethyl silicate, and sedimentation molding was performed using the slurry. When this was dried, the obtained molded body was insufficient in strength and was a fragile molded body that collapsed immediately when touched by hand. Further, when a part of the molded body was heated to 700 ° C. as in Example 1, it had almost no strength and was fragile enough to collapse immediately. Naturally, it was subjected to high-pressure impregnation and non-pressurized permeation. It wasn't something that could be used.

[Comparative Example 4] (Preform production by using organic binder, press molding and calcining)
An ethanol solution of polyvinyl butyral (hereinafter abbreviated as PVB) having a solid content of 20 w% was used in the silicon mixed powder having the formulation and weight of Example 1 so that the PVB ratio was 2 w% with respect to the silicon mixed powder. After the addition, a molded product was produced by press molding in the same operation as in Example 1. When the obtained molded product was calcined at 750 ° C., it became fragile enough to collapse when touched. The reason for this is thought to be that PVB functions as a binder for the silicon mixed powder at room temperature, but is burned down by calcining. From the above results, it was confirmed that the organic binder can be used to maintain the shape of the press-molded product, but the strength of the preform cannot be maintained by firing in the subsequent steps.

[Comparative Example 5] (Uses an organic-inorganic binder, prepares a preform by pre-baking at 850 ° C., and uses a non-pressurized permeation method)
The same amount of silicon mixed powder prepared by adding the same amount of ethyl silicate of an organic-inorganic binder to the mixture of three kinds of silicon powders having different average particle diameters used in Example 1 and stirring and mixing was used. Press molding was performed by the same method as in Example 1. The obtained press-molded product is placed in an electric furnace, heated to 850 ° C. at a heating rate of 50 ° C./hr, held at this temperature for 3 hours for firing, and then cooled to room temperature to form a silicon preform. Made.

When the surface of the fired body obtained above was observed, silicon was oxidized to SiO ₂ , which was discolored whitish. Further, since silicon became SiO ₂ and the volume increased, stress was generated on the surface to generate minute cracks, and it was not possible to obtain a defect-free preform.

[Comparative Example 6] (Using Mg powder and an organic-inorganic binder, preform is produced by calcining at 570 ° C.)
Mg powder having an average particle diameter of 80 μm was added to three types of silicon powder having different average particle diameters as used in Example 2, ethyl silicate was added to this mixture, and the mixture was mixed with a stirrer. In the same manner as in Example 2, press molding was performed to obtain a pressed product. Then, the press-molded product obtained above was fired and degreased at 570 ° C. for 3 hours to prepare a preform (baked body).

An attempt was made to infiltrate the preform (fired body) obtained above with a molten aluminum alloy in the same manner as in Example 2 without pressure. However, the aluminum alloy did not penetrate the preform (fired body) without pressure. It is considered that the reason is that by firing at 570 ° C., Mg added in the pressed product is oxidized to MgO, which cannot contribute to non-pressurized permeation.

[Comparative Examples 7 to 9] (Preform preparation using silicon powder of each average particle size alone)
The silicon powders having average particle diameters of 45 μm, 25 μm, and 5 μm used in the mixture of silicon powders in Example 1 were press-molded and pressed in the same procedure as in Example 1 except that 2700 g of each silicon powder was used as a single substance. The molded product was fired to prepare a preform. Then, the volume filling factor (Vf) was calculated for the preform obtained by using the obtained silicon powder having an average particle diameter of 45 μm, 25 μm, and 5 μm as a single substance in the same manner as in Example 1. .. As a result, the preform using 45 μm silicon powder has a filling factor of 50 v%, the preform using 25 μm silicon powder has a filling factor of 52 v%, and the preform using 5 μm silicon powder has a filling rate of 50 v%. The filling rate was 53v%. As described above, it was confirmed that the filling rate of any of the preforms obtained by using the silicon powder having each average particle size as a single substance was lower than that of the preforms of the examples, and the content was high. It was found that in order to prepare the preform of the above, it is necessary to mix and use metal powders such as silicon having different average particle diameters.

Table 1 summarizes the preform production conditions performed in Examples and Comparative Examples, the impregnation method of Al alloy and the like, and the properties of the obtained high metal powder-containing aluminum complex.

Claims (10)

A high metal having a process of producing a preform for obtaining a metal powder molded body (preform) having a high metal content and an impregnation step of aluminum or the like impregnating or impregnating the obtained preform with molten aluminum or an aluminum alloy. A method for producing a powder-containing aluminum composite.
In the process of producing the preform, two or more kinds of metal powder materials having different average particle diameters are selected from the metal powder materials having an average particle diameter of 1 μm or more and 200 μm or less and used as the metal raw material for the preform, and the metal raw material is used. Is molded and obtained by using a mixture obtained by adding and mixing at least one organic-inorganic binder selected from the group consisting of silicone resin, Si alkoxide and Al alkoxide in a liquid state or in a liquid state. By firing the molded product at a temperature of 300 ° C. or higher and 800 ° C. or lower, the organic matter in the molded product is removed, and the inorganic matter acts as an inorganic binder, so that the content (volume ratio) of the metal raw material is used. Obtained a metal powder molded body having a value of 55 v% or more.
In the step of impregnating aluminum or the like, the metal powder molded body obtained in the step of producing the preform is impregnated with a molten metal of aluminum or an aluminum alloy at a high pressure of 10 MPa to 200 MPa. How to make a body. A high metal having a process of producing a preform for obtaining a metal powder molded body (preform) having a high metal content and an impregnation step of aluminum or the like impregnating or impregnating the obtained preform with molten aluminum or an aluminum alloy. A method for producing a powder-containing aluminum composite.
Average particles from metal powder materials having an average particle diameter of 1 μm or more and ₂₀₀ μm or less (excluding Mg powder, AlMg powder, ZnMg powder, ZnAl powder, and Mg2Si powder) in the preform manufacturing process. Two or more kinds of metal powder materials having different diameters are selected as a metal raw material for preform, and 100 parts by mass of the metal raw material is composed of Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg _2Si powder. One or more powders selected from the group are added in an amount in the range of 0.2 to 5 parts by mass, and further, a group consisting of a silicone resin, Si alkoxide and Al alkoxide in a liquid state or a liquid state. By molding using a mixture obtained by adding and mixing at least one of an organic-inorganic binder selected from the above, and firing the obtained molded product at a temperature of 300 ° C. or higher and 500 ° C. or lower , the molded product is contained. A metal powder molded product having the above-mentioned organic matter removed and the inorganic matter acting as an inorganic binder and having a content (volume ratio) of the metal raw material of 55 v% or more was obtained.
A high metal powder-containing aluminum composite characterized by infiltrating an aluminum or an aluminum alloy into a metal powder molded body obtained in the preform manufacturing step in the impregnation step of aluminum or the like without pressure in a nitrogen atmosphere. Manufacturing method. The metal powder is one or more selected from silicon powder or silicon alloy powder containing silicon, titanium powder, iron powder or iron alloy powder containing iron, and nickel powder or nickel alloy powder containing nickel. The method for producing a high metal powder-containing aluminum composite according to claim 1 or 2. The method for producing a high metal powder-containing aluminum complex according to any one of claims 1 to 3, wherein the content (volume fraction) is 55 v% or more and 85 v% or less. The two or more kinds of metal powders having different average particle diameters include at least a metal powder A having an average particle diameter of 10 μm or less and a metal powder B having an average particle diameter of 40 μm or more. The method for producing a high metal powder-containing aluminum composite according to any one of claims 1 to 4, wherein the total amount of the metal powder contains at least 3% and the metal powder B contains 50% or more. The method for producing a high metal powder-containing aluminum composite according to any one of claims 1 to 5, wherein the organic-inorganic binder is at least one selected from the group consisting of Si alkoxide and Al alkoxide. A method for producing a preform for obtaining a metal powder molded body (preform) having a high metal powder content, which is used when impregnating molten aluminum or an aluminum alloy at high pressure to obtain a high metal powder-containing aluminum composite metal. And
A metal powder material having an average particle diameter of 1 μm or more and 200 μm or less contains at least a metal powder A having an average particle diameter of 10 μm or less and a metal powder B having an average particle diameter of 40 μm or more. Two or more kinds of metal powder materials having at least 3% in the total amount of the metal powder and containing 50% or more of the metal powder B and having different average particle diameters are selected as metal raw materials for preform. It is molded by using a mixture obtained by adding and mixing at least one organic-inorganic binder selected from the group consisting of silicone resin, Si alkoxide and Al alkoxide to a metal raw material in a liquid state or in a liquid state . By firing the obtained molded product at a temperature of 300 ° C. or higher and 800 ° C. or lower, the organic matter in the structure of the organic-inorganic compound is burnt and removed, and the inorganic matter acts as an inorganic binder to form the metal raw material. A method for producing a preform, which comprises obtaining a metal powder molded body having a content rate (volume ratio) of 55 v% or more. For obtaining a metal powder molded body (preform) having a high metal powder content, which is used when a molten aluminum or an aluminum alloy is infiltrated in a nitrogen atmosphere without pressure to obtain a high metal powder-containing aluminum composite metal. It ’s a method of making preforms.
From metal powder materials with an average particle size of 1 μm or more and 200 μm or less (excluding _each powder material of Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg2Si powder), at least a metal having an average particle size of 10 μm or less. A powder A and a metal powder B having an average particle diameter of 40 μm or more are contained, and the metal powder A is contained at least 3% in the total amount of the metal powder on a mass basis, and the metal powder B is contained in an amount of 50% or more. Two or more kinds of metal powder materials having different average particle diameters are selected as metal raw materials for preform, and Mg powder, AlMg powder, ZnMg powder, ZnAl powder and Mg _2Si powder are used for 100 parts by mass of the metal raw material. One or more powders selected from the group consisting of are added in an amount in the range of 0.2 to 5 parts by mass, and further, from silicone resins, Si alkoxides and Al alkoxides in a liquid state or in a liquid state. The molded product is formed by using a mixture added and mixed as at least one of the organic-inorganic binders selected from the above group , and the obtained molded product is fired at a temperature of 300 ° C. or higher and 500 ° C. or lower . A method for producing a preform, which comprises obtaining a metal powder molded body in which the organic matter in the metal is removed, the inorganic matter acts as an inorganic binder, and the content (volume ratio) of the metal raw material is 55v% or more. .. A high metal powder-containing aluminum composite having extremely few internal defects such as cavities, and the high metal powder-containing aluminum composite according to any one of claims 1 and 3 to 6, which utilizes high-pressure impregnation. A high metal powder-containing aluminum composite obtained by the production method of. A near-net high metal powder-containing aluminum composite having a shape similar to that of a product, and the high metal powder-containing aluminum composite according to any one of claims 2 to 6, which utilizes non-pressurized permeation in a nitrogen atmosphere. A high metal powder-containing aluminum composite obtained by the production method of.

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