JPH10140263A - Production of metal-ceramics composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of production of a metal-ceramics composite with low powder filling ratio, hitherto considered to be difficult because powder filling ratio can be reduced only to about 50vol.% by a penetration method. SOLUTION: The metal-ceramics composite is produced by forming a preform by the use of ceramic fibers or grains as a reinforcement and impregnating a metal as a base material into the preform. At this time, the preform is composed of an Al2 O3 powder prepared by incorporating a sintered Al2 O3 powder of 1-130μm average grain size by 10-90wt.% into an electromelted Al2 O3 powder of 1-100μm average grain size, and this perform is obtained by adding a colloidal silica solution or/and a colloidal solution of aluminum hydrate to the Al2 O3 powder, molding the resultant mixture, and then burning the resultant molded body. Further, an alloy, composed essentially of aluminum, is allowed to penetrate into the perform at 700-1000 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a composite material in which a metal is combined with a reinforcing material, and more particularly to a method of manufacturing a metal-ceramic composite material using ceramics as the reinforcing material.

[0002]

2. Description of the Related Art Metal-ceramic composite materials reinforced with ceramic fibers or particles have the properties of both metals and ceramics. For example, this composite material has rigidity, low thermal expansion, and wear resistance. It has excellent properties of ceramics such as ductility, and 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.

[0003] Methods for producing this composite material, particularly a composite material using aluminum as a matrix as a metal, include powder metallurgy, pressure casting, and vacuum casting. Among them, in powder metallurgy, powdered metal is mixed with granulated or whisker-shaped or fiber-shaped ceramics as a reinforcing material, molded, and the molded body is subjected to non-pressurization.
Alternatively, it was produced by firing under pressure. However, the powder filling rate of the reinforcing material in the composite material produced by this method is at most about 25% for whisker or fibrous fibrous material because sintering becomes difficult when the reinforcing material is increased, and The maximum was about 40%.

In the pressure casting method and vacuum casting method other than the powder metallurgy method described above, the wettability of the melted metal to the ceramic particles is poor. The filling factor was also at most about 40% at the maximum. Therefore, recently, in order to increase the powder filling rate of the reinforcing material, a preform made of ceramic fibers or particles as the reinforcing material is formed in advance, and a permeation method of permeating the base metal into the preform has been adopted. I have.

The infiltration method mainly involves forming a preform by adding water and a binder to a ceramic powder to form a slurry, forming the slurry by a sediment casting method in which the slurry is cast, and firing the formed body. According to this method, it is easy to form a preform having a high powder filling rate of 60 vol% or more, but it is difficult to form a preform having a low filling rate. The powder filling rate was reduced by mixing powder.

[0006]

However, even if carbon is mixed, the powder filling rate can be reduced to only about 50 vol%, and the preform obtained by this method is calcined in the atmosphere, so that carbon is not removed. And the strength of the preform is low. Further, there is also a problem that even if firing in the air, some carbon remains, which hinders penetration of aluminum or aluminum alloy.

The present invention has been made in view of the problems of the above-described method for producing a metal-ceramic composite material by the infiltration method, and has an object to form a high-strength preform having a low powder filling rate. Another object of the present invention is to provide a method for producing a metal-ceramic composite material from which a composite material having no problem with metal penetration can be obtained from the preform.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object. As a result, if the sintered Al ₂ O ₃ powder is mixed with the fused Al ₂ O ₃ powder, 30 to 60 vol% is obtained. That a high-strength preform having a powder filling rate of 5% can be formed, and a metal-ceramic composite having no problem with metal penetration can be obtained by infiltrating the preform with an alloy mainly composed of aluminum. And completed the present invention.

That is, the present invention relates to (1) a method for producing a metal-ceramic composite material in which a preform is formed by using ceramic fibers or particles as a reinforcing material, and a metal as a base material is penetrated into the preform. Is added to a fused Al ₂ O ₃ powder having an average particle size of 1 to 100 μm by adding a sintered Al ₂ O ₃ having an average particle size of 1 to 130 μm.
Comprises a powder from Al ₂ O ₃ powder containing 10 to 90 wt%, after formation method of the preform was molded by adding colloidal silica solution or / and colloidal solution of alumina hydrate Al ₂ O ₃ powder, the A method for producing a metal-ceramic composite material, characterized in that the method is a method of firing a molded body, and an alloy containing aluminum as a main component is infiltrated into the preform at a temperature of 700 to 1000 ° C. in addition, (2) sintered Al ₂ O ₃ powder, a metal according to claim 1, characterized in that the sintered Al ₂ O ₃ powder formed by calcining aluminum hydroxide - method of manufacturing a ceramic composite material (Claim 2). This will be described in more detail below.

[0010] As the preform, 1 to 100 µm
1 to 130 to the fused Al ₂ O ₃ powder having an average particle size of m
A sintered Al ₂ O ₃ powder having an average particle size of
The preform was made of Al ₂ O ₃ powder containing wt%.
Fused Al ₂ O ₃ powder had a mixing sintered Al ₂ O ₃ powder, the powder by the bulk density mixed much lower sintering Al ₂ O ₃ powder than fused Al ₂ O ₃ powder This is because the filling rate can be reduced. The reason why the average particle size of the powder is 1 to 100 μm for the electrofused Al ₂ O ₃ powder and 1 to 130 μm for the sintered Al ₂ O ₃ powder is that it is difficult to form a solid preform outside this range. The mixing ratio of the sintered Al ₂ O ₃ powder is preferably 10 to 90 wt%, preferably 10 wt%.
%, The powder filling rate does not decrease, and if it is higher than 90 wt%, the strength of the preform is remarkably reduced.

Another powder is added to the mixed Al ₂ O ₃ powder.
Up to about 0 wt%, they may be mixed. For example, SiC
When this powder exceeds 10 wt%, Si
The SiO ₂ on the C surface reacts with the metal to form S in the matrix.
A large number of brittle portions of i or Mg ₂ Si are generated, and the fracture toughness value is reduced. Further, a powder having a high Young's modulus such as WC may be mixed, but since the specific gravity is higher than that of Al ₂ O ₃ , the feature of “light weight” is lost. Other mixed powders include oxides such as mullite and silica, silicon nitride, nitrides such as aluminum nitride, titanium nitride and zirconium nitride, carbides such as titanium carbide and boron carbide, zirconium boride, titanium boride and the like. And the like, but any of them can be used.

The electrofused Al ₂ O ₃ powder may be a normal abrasive or a material used as a raw material for refractories. Is preferred because oxidation of the compound is suppressed. On the other hand, examples of the sintered Al ₂ O ₃ powder, refractory, release agent, may be sintered Al ₂ O ₃ powder used in such abrasive, the starting material was aluminum hydroxide, very particularly Porous and low bulk density sintered Al ₂ O ₃ powder (Electrofused Al ₂ O ₃ powder is less than 2.0 g / cm ³ , but sintered Al ₂ O ₃ powder obtained by firing aluminum hydroxide is 1 .0g / cm ³ before and after)
Depending on Even if such a sintered Al ₂ O ₃ powder having a low bulk density is mixed, a preform having sufficient strength can be formed by using a binder described later, and by increasing the mixing ratio, The powder filling rate can be greatly reduced, and the filling rate can be controlled by changing the mixing rate.

As a method for forming the preform, A
A method was employed in which a colloidal silica liquid or / and a colloidal liquid of alumina hydrate were added to l ₂ O ₃ powder, molded, and then the molded body was fired. The reason that the binder is a colloidal silica liquid or a colloidal liquid of alumina hydrate is that the strength of the preform can be improved. Hereinafter, each binder will be described in more detail.

The colloidal silica liquid includes a silica liquid stable in an alkaline region and a silica liquid stable in an acidic region. In a silica liquid stable in an alkaline region, the size of a colloid stabilized with Na ⁺ or the like is 5 to 5. A 100 nm silica liquid can be used. The concentration of silica in the liquid is 10-40wt
%, And the concentration of the alkali component of the stabilizer is preferably 0.4 wt% or less in terms of Na ₂ O.
If the concentration is higher than this, Al that has penetrated into the preform by Na ions easily becomes Al ₂ O _3, and the preform becomes high in strength, but the properties of the composite material, particularly, the bending strength and the fracture toughness decrease. Not preferred. Also, Al
Grain boundaries of ₂ O ₃ are vitrified to form closed pores, which hinders permeation.

On the other hand, in the case of a silica liquid which is stable in an acidic region, a silica liquid having an acidic and stable colloid having a size of 5 to 100 nm can be used. The concentration of silica in the liquid is in the range of about 10 to 40 wt% as described above, and the concentration of the alkali component is preferably 0.05 wt% or less in terms of Na ₂ O.

Next, a colloidal solution of alumina hydrate has a colloid size of 1 to 1000 nm, and is composed of Cl ^- and CH ₃ C.
OO ^- or NO ₃ ^- stabilized colloidal solution can be used. This colloidal solution of alumina hydrate and the above-mentioned colloidal silica solution can be used in combination. As a standard for mixing, the ratio of the silica component is set to 10 to 80 wt% with respect to the alumina component. A proper preform can be formed by adding an appropriate amount of these binders to Al ₂ O ₃ powder and molding and firing.

As a method for infiltrating a metal into the above preform, an alloy containing aluminum as a main component is used in an amount of 700 to
The penetration was performed at a temperature of 1000 ° C. The metal was an aluminum alloy, Al ₂ O ₃ powder wettability good, also the aluminum alloy is higher rigidity than the material, such as cast iron, due to specific gravity is low specific rigidity high preferred. If the infiltration temperature of this alloy is lower than this range, the alloy will not melt, and if it is higher, aluminum will be oxidized.

[0018]

More particularly the manufacturing method of the embodiment of the present invention, first, the fused Al ₂ O ₃ powder having an average particle size of 1~100μm as reinforcement, baked with an average particle size of 1~130μm 10% to 90% by weight of Al ₂ O ₃ powder and 10% of other ceramic powder if necessary
The mixed powder is used below. The Al ₂ O ₃ powder may have a single particle size for both electrofusion and sintering. However, mixing two types of powders can increase the strength of the preform, This is desirable because the rate can be easily controlled. The molding is performed by a sediment cast method.

The above-mentioned Al ₂ O ₃ powder is mixed with about 10 to 50 wt% of ion-exchanged water,
About 0 wt% (alumina or silica component is 0.1 wt%).
2 to 10 wt%), and if necessary, defoamer 2w
Add about t% or less and urea about 2 wt% or less. If the amount of the binder is too small, the strength of the formed preform is small, which hinders the formation of a composite. If the amount is too large, closed pores are formed and the composite cannot be formed.

The obtained composition is mixed for 1 hour or more using a pot mill or the like. When the ball is put into the pot mill, the reinforcing material is crushed by the ball, so the mixing time is at most about 100 hours or less.
There is no particular limitation. The mixed slurry is subjected to sedimentation molding, that is, sediment casting by applying vibration. If the viscosity of the slurry is high, the powder does not settle,
0 poise or less is desirable. Normally, a silicone rubber mold is used, but a mold of plastic, aluminum or the like may be used, and there is no particular limitation. During the sedimentation of the particles, vibration is applied as much as possible to improve the filling. The obtained compact is frozen and demolded. Freezing is not limited as long as the water is frozen. The demolded compact is fired at a temperature of 800 to 1600 ° C. to form a preform.

The obtained preform is unpressurized or pressurized in a nitrogen stream at a temperature of 700 to 1000 ° C.
-Infiltrate a Si-Mg-based or Al-Mg-based aluminum alloy. After infiltration, 50 to 3
Cool at a cooling rate of 00 ° C / h. During cooling, the temperature may be maintained at a temperature immediately before the matrix solidifies for about 1 to 10 hours in order to suppress the occurrence of thermal strain.

When a metal-ceramic composite material is prepared by the above-described method, a high-strength preform having a powder filling rate of 30 to 60 vol% can be formed, and a metal-ceramic having no problem in penetration of metal from the preform. A composite material is obtained.

[0023]

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

(Examples 1 to 6) (1) Formation of preform Electrolytic Al ₂ O ₃ having an average particle size shown in Table 1 as a reinforcing material
Sintered Al ₂ O ₃ powder having the average particle size shown in Table 1 obtained by calcining aluminum hydroxide was mixed with the powder at the ratio shown in Table 1, and 25 to 45 wt.
%, Na ⁺ colloidal silica solution stabilized with (Na 0.05 wt% in ₂ O equivalent) or NO ₃ ^- adding a colloidal solution of alumina hydrate was stabilized by an amount shown in Table 1, to power the ball Mix in a fresh pot mill for 5-16 hours. The obtained slurry was poured into a silicone rubber mold having a size of 180 × 25 × 25 mm, and vibration was applied for 2 hours to set a reinforcing material and settle. After molding, the entire rubber mold was cooled to -25 ° C, frozen, and demolded. After demolding, firing was performed at a heating rate of 50 ° C./h in the air atmosphere under the firing conditions shown in Table 2,
The preform was formed by cooling to room temperature at a temperature lowering rate of ~ 300 ° C / h.

(2) Preparation of Metal-Ceramic Composite Material A
An alloy of 1-5Mg was placed, and the alloy was infiltrated into the preform in a nitrogen gas stream at 830 ° C. (2 liters / min: furnace volume 0.03 m ³ ). C., and kept at that temperature for 5 hours, and then cooled again to room temperature at 100.degree. C./h to produce a metal-ceramic composite material.

(3) Evaluation The bulk density of the obtained preform was measured by Archimedes' method, and the powder filling rate of the preform was determined. Also, JIS
The bending strength was determined by R1601. Furthermore, the obtained composite material was cut, and its surface was observed with a microscope.
The presence of pores of m or more and the state of metal penetration were investigated. Table 2 shows the results.

Comparative Example 1 As a comparison, a preform was prepared in the same manner as in Example 3 except that only sintered Al ₂ O ₃ powder was blended in the proportions shown in Table 1 without using electrofused Al ₂ O ₃ powder. After forming, a metal-ceramic composite material was prepared and evaluated.
The results are also shown in Table 2.

[0028]

[Table 1]

[0029]

[Table 2]

As is apparent from Table 2, in the examples, the powder filling rate of the preform was 60 vol%.
Lower versions, on the order of 30 vol%, were also made. And although the strength is reduced by increasing the sintered Al ₂ O ₃ powder,
The flexural strength was 2.7 MPa or more, which was much higher than 1 MPa, which is the strength that can penetrate metal without any problem. Also, in the composite material, the permeation state of the metal was good, and pores of 1 mm or more were not observed. This indicates that the strength of the preform can be maintained at 1 MPa or more even if the powder filling rate of the preform is reduced, so that the metal can penetrate without any problem.

On the other hand, in Comparative Example 1, although the powder filling rate of the preform could be reduced to 42 vol%, the strength of the preform was 0.1 MPa since no fused Al ₂ O ₃ powder was contained. And below 1MPa,
As a result, cracks were formed due to metal penetration, and the metal could not be permeated.

[0032]

As described above, if a metal-ceramic composite material is produced by the method of the present invention, a high-strength preform having a powder filling rate of 30 to 60 vol% can be formed, and there is no problem in metal penetration. A composite material of metal-ceramics was obtained. Thereby, a metal-ceramic composite material having a low powder filling rate can be easily produced, and the filling rate can be easily controlled.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Heishiro Takahashi 314-1 Matsudo Nitta, Matsudo City, Chiba Prefecture (72) Mutsui Hayashi 560 Omaki, Urawa City, Saitama Prefecture

Claims (2)

[Claims] 1. A method for producing a metal-ceramic composite material in which a preform is formed by using ceramic fibers or particles as a reinforcing material and a metal as a base material is penetrated into the preform, wherein the preform has a size of 1 to 100 μm. 1-130 μm to the fused Al ₂ O ₃ powder having an average particle size
Al ₂ O ₃ powder having an average particle size of 10 to 90 wt.
% Of Al ₂ O ₃ powder. The preform is formed by adding a colloidal silica liquid or / and a colloidal liquid of alumina hydrate to the Al ₂ O ₃ powder and molding, and then firing the molded body. In the preform, an alloy containing aluminum as a main component is used in the preform.
A method for producing a metal-ceramic composite material, characterized by infiltrating at a temperature of ° C. 2. A sintered Al ₂ O ₃ powder, a metal according to claim 1, characterized in that the sintered Al ₂ O ₃ powder formed by calcining aluminum hydroxide - method of manufacturing a ceramic composite material.