JPH1180860A - Production of metal-ceramics composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, the conventional metal-ceramics composite material is inferior in heat resistance in the case the content of Mg is increased, and though the heat-resistance can be improved in the case the Mg content is reduce, time is required for the infiltration of metal. SOLUTION: In the method for producing a metal-ceramics composite material in which a preform is formed with ceramics powder as a reinforcing material, and a metal as a base material is infiltrated into the preform, the method forming the preform is the one in which AlN powder of 1 to 150 μm average particle size having 40 to 80 vol.% powder filling ratio is added with an inorganic binder, which is molded and sintered, and the method for infiltrating the metal is the one in which the formed preform is infiltrated with an alloy essentially consisting of aluminum and contg. 1 to 10 wt.% Mg at 860 to 1000 deg.C in a nitrogen air flow.

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 metal-ceramic composite material in which a metal is combined with a reinforcing material, and more particularly to a method for producing a metal-ceramic composite material having improved creep resistance.

[0002]

2. Description of the Related Art A ceramic-metal composite material reinforced with ceramic fibers or particles has both characteristics of ceramic and metal. For example, this composite material has high rigidity, low thermal expansion property, abrasion resistance, etc. It has the excellent properties of ceramics and the excellent properties of metals such as ductility, high toughness, and high thermal conductivity. As described above, since it has both the characteristics of ceramics and metal, which have been considered difficult, it has been drawing attention as a next-generation material from industries such as mechanical device manufacturers.

As a method for producing this composite material, particularly a composite material using aluminum as a matrix as a metal, methods such as powder metallurgy, high pressure casting, and vacuum casting have been conventionally known. However, all of these methods are not capable of increasing the content of ceramics as a reinforcing material, require a large-sized pressurizing device, are difficult to form near nets, and are extremely expensive. It was not satisfactory.

Accordingly, recently, a non-pressurized metal infiltration method developed by Rankside Company of the United States has attracted particular attention as a manufacturing method for solving the above problem. This method uses SiC or A
An aluminum ingot containing Mg is brought into contact with a preform formed of a ceramic powder such as l ₂ O ₃ ,
This is a method in which the molten aluminum alloy is heated to 700 to 900 ° C. in an N ₂ atmosphere to penetrate the preform. This is because Mg in the alloy volatilizes while being heated to the infiltration temperature and reacts with N ₂ to form magnesium nitride on the surface of the ceramic powder (N ₂ + 3Mg → Mg ₃ N ₂ ).
This Mg ₃ N ₂ reacts very easily with Al (Mg ₃
(N ₂ + 2Al → 2AlN + 3Mg), the molten aluminum alloy permeates the preform without pressing. The aluminum nitride (AlN) produced by this reaction is deposited as a thin layer on the ceramic surface, and Mg dissolves into the aluminum alloy. As the Mg concentration increases, the penetration rate of the aluminum alloy into the preform increases. , Works to shorten the permeation time.

Further, according to this method, the content of ceramics can be varied as wide as 30 to 85 vol% and a high range, and the preform formed by this method has a high degree of freedom in its shape. It is also possible to make quite complex shapes with near nets. As described above, this method does not require a pressurizing device, can increase the content of ceramics, and enables near-net molding. Therefore, this method is an excellent method that solves the above-described problem. .

[0006]

However, the composite material produced by this method has a problem in that it has poor heat resistance. This is because the Al-Mg based alloy (5
000 series) is generally called hydronarium, and among aluminum alloys, ultra super duralumin (Al-Zn-
Mg, 7000 series), duralumin (Al-Cu, 20
It has the highest strength next to (00 series) and does not contain heavy metals, so it is often used in semiconductor and liquid crystal manufacturing equipment.
High temperature and high vacuum environment (for example, 500 ° C., 10 ^-5 P
There are many devices used in a), and when used under such high temperature and high vacuum, there are two problems regarding heat resistance described below.

One of the problems is that the Al-Mg alloy containing Mg has a low melting point, and has a poor creep resistance due to the low melting point. Since the matrix in the metal-ceramic composite material is an alloy containing aluminum as a main component, its creep resistance is greatly affected by the heat resistance of the matrix. For example, the melting point of Al-5Mg is about 570 ° C, and the melting point of Al-10Mg is 500 ° C.
Therefore, the temperature at which the metal-ceramic composite material using these alloys as a matrix can be used without deformation, depending on the load, is up to about 450 to 500 ° C, depending on the load. Have difficulty.

[0008] Second, the vapor pressure is extremely low.
Since it is easy to volatilize, it is difficult to achieve a high degree of vacuum at a temperature of 400 ° C. or more, and when returned to normal pressure, the volatilized Mg solidifies and is generated as dust. It was very difficult to use the above-mentioned vacuum apparatus. It is conceivable to use the generated dust after cleaning it, but this also requires considerable time and effort to remove the dust, and it is also difficult to use the dust.

In order to improve the heat resistance, that is, the creep resistance, the present inventors have developed a metal-ceramic composite material capable of infiltrating an aluminum alloy having a Mg content of 1% by weight or less into a preform and a metal-ceramic composite material. A manufacturing method was proposed (Japanese Patent Application No. 9-213847). This is because the content of Mg can be suppressed to 1% or less, so that the creep resistance is greatly improved. However, this composite material has a problem that, since the content of Mg is small, the amount of reaction with N ₂ is reduced, the function of accelerating permeation is reduced, and the permeation speed is reduced. For example, in the case of a conventional product, while the aluminum alloy can penetrate a thickness of 20 mm in a N ₂ stream at 850 ° C. for about 20 hours, it takes about three times as long under the same conditions. It was difficult to make thick products.

The present invention has been made in view of the above-mentioned problems of the composite material of ceramic and metal, and has as its object to improve the creep resistance without increasing the penetration time. An object of the present invention is to provide a method for manufacturing a ceramic composite material.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object. As a result, even if an aluminum alloy containing 1% or more of Mg is used, if the infiltration temperature is limited,
The inventors have found that the creep resistance is improved, and have completed the present invention.

That is, the present invention provides (1) a method for producing a metal-ceramic composite material in which a preform is formed by using ceramic powder as a reinforcing material, and a metal as a base material is penetrated into the preform. The method is a method in which an inorganic binder is added to AlN powder having an average particle diameter of 1 to 150 μm having a powder filling rate of 40 to 80 vol%, and the mixture is calcined. 1-10% by weight of Mg for reform
Alloy containing aluminum as the main component
The gist is to provide a method for producing a metal-ceramic composite material, which is a method of infiltrating at a temperature of 60 to 1000C. This will be described in more detail below.

As a method of manufacturing the above-mentioned composite material, first, a method of forming a preform is performed on an AlN powder having a powder filling rate of 40 to 80 vol% and an average particle diameter of 1 to 150 μm.
A method was employed in which an inorganic binder was added to mold and fired.
The powder filling rate of the ceramic powder is preferably from 40 to 80 vol%, and if it is lower than 40 vol%, it is not preferable because it is difficult to form a preform. If it exceeds 80 vol%, the voids in the preform are narrow and metal penetration becomes difficult. Not preferred. The average particle size of the powder is 1 to 150.
If it is smaller than 1 μm, penetration of aluminum becomes difficult, and if it is coarser than 150 μm, it becomes difficult to form a preform.

As a method of infiltrating a metal into the formed preform, an alloy containing aluminum as a main component containing 1 to 10% by weight of Mg is mixed in a nitrogen stream at 860 to 100%.
A method of infiltrating at a temperature of 0 ° C. was adopted. By limiting the metal penetration temperature to 860 to 1000 ° C., the creep resistance of the composite material is improved. Metal penetration of 700-10
It is carried out at a temperature of 00 ° C., and most of the time, it is conducted in a temperature range of 800 to 850 ° C. It has been found that the creep resistance is improved even if it is contained more. If the temperature is lower than 860 ° C., the creep resistance is not improved, and if it exceeds 1000 ° C., Al-M
The g-based metal is oxidized.

[0015] In order to find out the reason for improving the creep resistance, observation with an optical microscope revealed that AlN particles had become smaller. Although the detailed mechanism is unknown, it is assumed that the refinement of the AlN particles observed in the present invention contributes to improving the creep resistance. Thus, it is suggested that the only way to improve the creep resistance of the composite material is to reduce the amount of Mg and improve the heat resistance.

The amount of Mg contained in the metal is as follows:
The content is preferably 1 to 10% by weight, and if it is less than 1% by weight, the effect of promoting metal penetration is small. On the other hand, if the content is more than 10% by weight, the evaporation of Mg increases at the time of permeation of the metal, causing a difference in the permeation rate, and a portion of the permeation remaining is undesirably generated. Thus, the creep resistance is improved, but the Mg
Is not improved because of the high content of Mg, and when used under high-temperature and high-vacuum conditions, the Mg content is 1% by weight as disclosed in Japanese Patent Application No. 9-13847. The following aluminum alloys must be used.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention will be described in more detail. First, an AlN powder having an average particle size of 1 to 150 .mu.m is prepared as a reinforcing material, and an inorganic binder and an organic binder if necessary. And mix.
Any mixing method may be used as long as it can be uniformly mixed. However, care must be taken when mixing with water.
That is, AlN reacts with water and decomposes. In order to avoid this problem, AlN powder whose surface is coated with silica is commercially available and may be used.

The resulting mixture is shaped. The molding method is
There are sedimentation molding, injection molding, CIP molding and the like, but any method may be used. In short, any method can be used as long as it can maintain the form of the preform to penetrate the metal under no pressure and does not hinder the penetration. As an example, the sedimentation molding is described. For example, a binder such as ammonium silicate is added to the above-mentioned ceramic powder and metal powder in an amount of 3 to 10% by weight, ion exchange water is 20 to 40% by weight, and an antifoaming agent if necessary. , And wet-mix with a pot mill. A small amount of medium may be added to increase the mixing efficiency.However, in this case, the particle size distribution of the ceramic powder may be changed and the powder filling rate may not be as intended. The mixing is preferably performed within 10 hours, at which the crushing of the powder does not proceed. The mixed slurry is cast and formed while vibrating. The mold is usually a silicone rubber mold, but may be a mold of plastic, aluminum, or the like, and is not particularly limited. During the settling of the particles after casting, vibration is applied as much as possible to improve the filling. It is frozen and demolded to obtain a molded body.

The obtained molded body is fired at a temperature of 900 to 1100 ° C. to form a preform. An aluminum alloy containing 1 to 10% by weight of Mg is placed on the upper surface of the formed preform, and 860 to 1000 in a nitrogen stream without pressure.
After melting at a temperature of ° C and infiltrating the molten metal into the preform, the preform is cooled at 50 to 300 ° C / hr to produce a composite material.

If a metal-ceramic composite material is produced by the above method, a metal-ceramic composite material having excellent creep resistance can be obtained even if it contains 1% or more of Mg.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention and Comparative Examples.

(Example) (1) Formation of preform Silica-coated AlN powder (manufactured by Dow Chemical Company) having an average particle size of 16 μm was used as a reinforcing material, and a colloidal silica liquid was used as a binder and the silica solid content was changed. An amount of 2 parts by weight was added to 100 parts by weight of the ceramic powder, 30 parts by weight of ion-exchanged water was further added, and the mixture was mixed in a pot mill without a medium for 16 hours.
The obtained slurry was poured into a silicon-rubber mold from which a molded body of 200 × 200 × 20 mm was obtained, sediment cast (sedimentation molding) was performed, and cooled to −30 ° C. to obtain a frozen product. The obtained frozen product was fired at 700 ° C. for 5 hours to form a preform.

(2) Preparation of Composite Material 200 g of powder obtained by mixing Al ₂ O ₃ powder and Mg powder 150 μm under at a weight ratio of 9: 1 on the upper surface of the preform.
Was spread thinly using a sieve, and an aluminum alloy twice the amount of the preform was further placed thereon.
After non-pressurized infiltration at a temperature of 5 ° C. for 24 hours, the mixture was gradually cooled to produce a metal-ceramic composite material. The aluminum alloy used was Al-5Mg, Al-2Mg, Al-1M
g and pure Al.

(3) Evaluation The bulk density of the obtained preform was measured by the Archimedes method, and the powder filling rate was determined. As a result, it was 70 vol%. Further, the obtained composite material was cut, and the cut surface was visually observed to check the state of penetration of the metal. As a result, Al-
In the composite material using 1Mg and pure Al, a part of the unpermeated portion was observed, but the composite material using Al-5Mg and Al-2Mg was completely permeated. Further, a test piece having a length of 40 × width 4 × thickness of 3 mm was cut out from the obtained composite material, and a 4-point bending stress of 16 MPa was applied to the test piece.
The temperature was increased to 700 ° C. at a rate of 5 ° C./min, and the creep characteristics were measured. As a result, it hardly creeped.

(Comparative Example) As a comparison, a preform was formed in the same manner as in the above example except that the infiltration temperature of the aluminum alloy was 850 ° C., a metal was infiltrated, and a composite material was prepared and evaluated. As a result, as for the permeation state of the metal, in the composite material using Al-1Mg and pure Al as in the above-described example, a part of the composite material using non-permeation was observed.
The composite material using Mg was completely infiltrated. Further, from the obtained composite material, length 40 × width 4
× Cut out a test piece having a thickness of 3 mm.
A 4-point bending stress of Pa was applied, and the temperature was increased to 700 ° C. at a rate of 5 ° C./min to measure creep characteristics. As a result, a composite material using Al-5Mg and Al-2Mg is:
At 540 ° C., the composite material using Al-1Mg is 560
Fracture at ℃. The composite material using pure Al is 70%.
Little creep up to 0 ° C. This indicates that when the permeation temperature of the metal is lower than 860 ° C., the heat resistance is greatly reduced.

[0026]

As described above, according to the method for producing a metal-ceramic composite material of the present invention, a metal-ceramic composite material having good heat resistance even when the Mg content is 1% or more. Is now available.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mutsumi Hayashi 560 Omaki, Urawa-shi, Saitama (72) Inventor Heishiro Takahashi 314-1 Matsudo-Shinda, Matsudo-shi, Chiba (72) Inventor Takeshi Higuchi Tokyo Higashi-Kurume, Tokyo 1-3-9 Hikawadai, City (72) Inventor Tomiwa Koyama 1-3-1-805, Ukima, Kita-ku, Tokyo

Claims (1)

[Claims] 1. A method for producing a metal-ceramic composite material in which a preform is formed by using ceramic powder as a reinforcing material and a metal as a base material is penetrated into the preform, the method for forming the preform comprises 40 to 80 vol.
A having an average particle size of 1 to 150 μm
This is a method in which an inorganic binder is added to 1N powder, and the mixture is molded and fired. The method of infiltrating the metal is to form an alloy mainly containing aluminum containing 1 to 10% by weight of Mg in a preform formed in a nitrogen stream. A method of infiltrating at a temperature of 860 to 1000 ° C.