JPH0514779B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a conductive composite material and a method for producing the same. [Background Art] When particles are dispersed in a conductive material such as Ag, Au, or Cu to strengthen it, the distance between the particles becomes a problem. When an external force is applied, the material deforms, and at this time, the dislocations move as the material deforms. It can be said that making it difficult for dislocations to move makes it difficult to deform and increases hardness. The external force σ required to move the dislocation is expressed as follows: σ=μb/2πλμ: rigidity b: Vargas vector λ: interparticle distance. Therefore, if the interparticle distance λ is reduced, the force σ that attempts to move the dislocations becomes larger, making it difficult for the dislocations to move, resulting in a hard conductive composite material that is difficult to deform. In order to reduce the interparticle distance, the dispersed particles may be made smaller and the content of the particles may be increased. Ultrafine particles of 0.01 to 1 μm are commercially available, which are made by evaporating metal in vacuum. A dispersion strengthened powder can be made by mixing two such ultrafine particles, compacting, sintering, and mechanically crushing. 0.07μm Ag ultrafine particles and 0.02μm Ni
When ultrafine particles are made into powder using the above method, Ag
Figure 2 shows a micrograph showing the dispersion state of the Ni particles inside. Ni particles account for 5% of the total weight of Ag and Ni particles. In the photograph in Figure 2, the small granular parts are Ni particles, and the sea-like part surrounding them is the Ag matrix. As seen in this photo, many ultrafine Ni particles are aggregated, and it is difficult to separate and disperse the ultrafine particles one by one. Moreover, the distribution of these agglomerated masses is non-uniform, and there is a fairly wide region containing only Ag and no Ni particles. This causes an overall decrease in hardness. Furthermore, such products currently have drawbacks such as being expensive and difficult to adopt as industrial products. When reinforcing As, there is also a method of mixing Ni particles and Ag particles that are difficult to dissolve in Ag, molding, sintering, and mechanically crushing to produce powder of a predetermined size. In this case, As and Ni particles generally have a size of several to 50 μm (350 mesh or less).
Therefore, as shown in FIG. 3, some of the Ni particles aggregate, and Ni particles with a size of 1 to 20 μm are dispersed, reducing the effect of dispersion strengthening. JP-A-61-147827 discloses that in Ag, 1 to
An electrical contact material in which 20 micron Ni particles and submicron Ni particles are uniformly dispersed and a method for manufacturing this material are disclosed. As previously mentioned,
In order to increase the dispersion strengthening effect, it is necessary to reduce the distance between dispersed particles. However, in the invention disclosed in the above publication, two sizes of Ni
The particles are dispersed, and large particles ranging from 1 to 20 microns are mixed in. Therefore, the effect of dispersion reinforcement was lower. The manufacturing method for this material is to melt Ag and Ni at a temperature higher than the melting point of Ni, spray this to obtain a powder, mold this powder, and then sequentially sinter, compress, hot press, and extrude. ing. Since the contact material obtained is as described above, the powder has two different sizes of dispersed particles. [Objective of the Invention] In view of the above, the present invention has been developed to increase hardness without significantly changing electrical properties compared to conventional conductive composite materials, and to reduce tackiness, abrasion resistance, and deformation at high temperatures. It is an object of the present invention to provide a conductive composite material with a small amount of conductive material, and to provide a method for producing such a conductive composite material. [Disclosure of the invention] In order to achieve the above object, the first invention
In the matrix metal (A), one or more particles with a particle size of 0.01 to 1 μm made of a metal (B) that separates into two phases from the metal (A) are dispersed, and the metal (A) and the metal (B) are dispersed in the matrix metal (A). ), the second invention includes a metal (A) and a metal (B) that separates into two phases from the metal (A), Metal (B) is 0.5 to 20% of the total weight of metal (A) and metal (B).
By rapidly cooling and solidifying the molten metal at a ratio of
One or more types of particles are dispersed, and metal (A)
Metal (B) is 0.5 to 20% of the total weight of
The gist of this paper is a method for manufacturing a conductive composite material that obtains a conductive composite material having the following properties. These inventions will be explained in detail below. A metal (B) that separates into two phases from the matrix metal (A) is one that does not form a uniform solid phase with the metal (A), that is, one that does not form a solid solution (not limited to one that does not form at all), (including those to a lesser extent). It does not matter whether metal (A) and metal (B) form a uniform liquid phase in the molten state, but it is better to create a uniform liquid phase when metal (B) becomes a solid phase. It is preferable because it is easily dispersed uniformly in the metal (A) in a fine state. The metal (A) is not particularly limited, and examples thereof include Ag, Au, and Cu. The metal (B) can be selected from various types depending on the matrix metal (A), and is not particularly limited. For example, metal
When (A) is Ag, the metal (B) is Ni, Cr,
At least one selected from the group consisting of Fe, Co, Si, Rh, and V is preferred. When the metal (A) is Au, the metal (B) is preferably at least one selected from the group consisting of Ge, Si, Sb, and Rh. When metal (A) is Cu, metal (B) is
Fe is preferred. If these combinations are selected as metal (A) and metal (B), it is easy to make the metal (B) more finely and uniformly dispersed. The amount of metal (B) dispersed is the amount of metal (A) and metal (B)
It should be 0.5 to 20% of the total weight.
When it is less than 0.5%, the amount of dispersed particles is small, so the spacing between the particles becomes large, and the effect of dispersion strengthening is reduced. When it exceeds 20%, the amount of individual large particles that are not finely dispersed in the metal (A) increases. Metal (B) is a metal in the form of particles with a particle size of 0.01 to 1 μm.
(A) must be dispersed in 0.01μ
If it is less than m, a problem arises in that the conductivity of the metal (A) decreases. If it exceeds 1 μm, a problem arises in that the effect of dispersion strengthening is small. In reality, metal (B) particles with a particle size of more than 1 μm and less than 5 μm are
There is no problem even if it is contained in an amount of about 5 wt% or less based on the total metal (B) particles in the metal (A) matrix. The conductive composite material of this invention can be manufactured by various methods. For example, if a rapid solidification method is used, the metal (B) becomes particles within the above particle size range and is likely to be dispersed in the metal (A) matrix. Not particularly necessary. Amorphous fibers are produced by jetting molten metal into a rotating disk (rotating drum) surrounded by a film of water, and rapidly cooling and solidifying the molten metal. Powders can also be produced by changing the rotational speed of the rotary disk in the equipment used to carry out such methods. Conventionally, metals in solid solution with each other were melted and rapidly solidified. In the manufacturing method of this invention, metal particles that do not dissolve in solid solution with each other at room temperature are melted, mixed, and then rapidly solidified to produce a powder in which metal particles that do not dissolve in solid solution with each other are uniformly and finely dispersed in the matrix metal. There are characteristics. The rapid solidification method is not particularly limited, but a rotating liquid spray method and a high-pressure gas atomization method are preferred.
According to these methods, it is possible to obtain a conductive composite material in which the metal (B) is more finely and uniformly dispersed in the matrix metal (A). To explain more specifically, for example, Ag−
To make 4.6wt%Ni alloy powder, Ag and
Ni is placed in a graphite crucible at a ratio of 65.4wt%Ag and 4.6wt%Ni, and the melt temperature is brought to 1650℃ by high frequency melting. In the case of the spraying method in a rotating liquid, this molten metal may be jetted from a nozzle hole with a diameter of 0.1 to 0.2 mm into a water film formed on the inner wall of a rotating drum. In addition, in the case of high-pressure gas atomization method, the diameter is 0.1 to 5
The metal flow ejected from the mm nozzle is 50 to 100Kg/ ^cm2.
It can be sprayed with high-pressure inert gas. FIGS. 4 and 5 show an example of an apparatus used in the rotating liquid spray method. In these figures, 1
is a cylindrical rotating drum with one end closed, 2 is a cooling liquid, 3 is a blowing furnace, 4 is a blowing nozzle, 5 is a molten metal (molten metal), 6 is a quenched powder, 7 is a heating device, and 8 is a driving device. be. Rotating drum 1 by drive device 8
rotates. A film of cooling liquid 2 is formed on the inner wall of the rotating drum 1 by centrifugal force so as to cover the inner wall. Metal (A) and metal (B) are melted in the ejection furnace 3 by the heating device 7. This molten metal 5 is
Due to the pressure of the gas from the hole in the upper part of the gas, it is ejected from the ejection nozzle 4 into the cooling liquid 2 and is quenched to form a quenched powder 6. When producing the conductive composite material of the present invention by a rapid solidification method, the cooling rate is preferably about 10 ⁴ to ^{10 5} °C/sec. or more. Cooling rate is 10 ⁴ ~ 10 ⁵
°C/sec. If it is below this level, the dispersibility of the metal (B) particles may deteriorate. The temperature of the molten metal (molten metal) is preferably 100°C or more higher than the melting point of the metal (B), more preferably 200°C or more higher. If the temperature is not 100°C or more higher than the melting point of metal (B), large single-phase particles of metal (B) may appear. In order to achieve the above cooling rate in the rotating liquid spray method,
It is preferred that the molten metal is instantaneously jetted into the cooling water, and the distance between the molten metal spout such as a nozzle and the surface of the cooling water is preferably 10 mm or less, more preferably 5 mm or less. If the distance is greater than 10 mm, the dispersibility of metal (B) particles in the resulting conductive composite material may deteriorate. Further, the velocity V of the cooling water needs to be sufficiently faster than the velocity v of the jet flow, and it is preferable that 1.5≦v/v≦2.0. When the velocity of the cooling water and the velocity of the jet stream are similar, when the velocity of the cooling water is slower, or when the velocity of the cooling water is extremely faster, metal (B ) Particle dispersibility may deteriorate. Furthermore, to prevent this further fear, the temperature of the cooling water should be 10
The temperature is preferably below 4°C, more preferably below 4°C. In addition, from the point of view of the cooling effect, it is preferable that the cooling water is flowing rather than being stationary. Next, an embodiment of the present invention will be explained in more detail with reference to a photomicrograph showing one embodiment of the present invention. In addition, in each of the micrographs in Figures 1 to 3, the actual measured length of 6.5 mm in the photograph is the length
Compatible with 10μm. FIG. 1 is a microscopic photograph showing the structure of an example in which the conductive composite material of the present invention is a powder. This conductive composite material is made of Ag−4.6Ni
(Ni: 4.6wt%, balance Ag) molten metal was rapidly solidified as described above. Figure 2 shows the microscopic structure of conductive powder prepared by mixing 0.07 μm ultrafine Ag powder and 0.02 μm ultrafine Ni powder in a ratio of 5wt% Ni and the balance being Ag, molding, and sintering. It's a photo. Figure 3 shows the normal
It is a micrograph showing the structure of Ag-5Ni conductive powder. This powder is made by mixing electrolytic Ag powder of several to 50 μm and carbonyl Ni powder of the same size.
It is made by molding and sintering. As seen in the photograph in Figure 1, Ni is dispersed in the rapidly solidified powder with a size of approximately 0.5 μm. There are very few particles with extremely different sizes. As seen in the photograph of FIG. 2, in the powder made from ultrafine powder, Ni aggregates with a size of about 1 to 10 μm. As seen in the photograph in FIG. 3, in the conventional powder, Ni is dispersed in a size of 1 to 20 μm. Thus, it can be seen that in the conductive powder of the present invention, the dispersed metal is very finely dispersed compared to other powders. In the above embodiments, the conductive composite material of the present invention was explained as being obtained in the form of powder, but the conductive composite material of the present invention can be used in other forms other than powder, for example, in the form of a strip,
It can also be obtained in the form of fibers, etc., and the shape is not particularly limited. The conductive composite material according to the present invention has dispersed metal
Since (B) is very finely dispersed in the matrix of metal (A), it has greater hardness than conventional products. Therefore, the conductive composite material according to the present invention is difficult to deform, and the adhesiveness between the materials is reduced. Since it has high hardness at room temperature, it has low abrasion and deformation at high temperatures.
Furthermore, the electrical characteristics have not changed much compared to conventional ones. The electrical properties of the conductive composite material of this invention vary depending on the conductivity and content of the dispersed metal (B), but the inventors have confirmed that the metal (B) with a particle size of about 0.01 to 1 μm B) The particles are metal (A)
When dispersed in a proportion of 0.5 to 20% based on the total weight of the metal (B) and the metal (B), there was almost no change in conductivity. Therefore, the conductive composite material according to the present invention is a material that can be used in a wide range of applications such as electrical parts and conductive pastes. Examples will be shown below, but the present invention is not limited to the examples. Example 1 Ag and Ni were placed in a graphite crucible at a ratio of 95 wt% Ag and 5 wt% Ni, and the melt temperature was brought to 1650°C by high frequency melting. A temperature of 4°C was formed on the inner wall of a 600mm diameter drum rotating at 500rpm with an argon back pressure of 4.5Kg/ ^cm2 through a 120μm diameter ruby nozzle hole.
It erupted into a film of water. At this time, the angle between the water film and the spouted molten metal was 60°, and the distance between the lower end of the nozzle and the water surface was 4 mm. In this way, a powdery conductive composite material of 100 to 200 μm was produced and annealed at 850° C. for 3 hours in an Ar atmosphere. Measure the hardness of the sample obtained in this way,
It was evaluated as dispersion reinforcement. Example 2 Ag and Ni were placed in a graphite crucible at a ratio of 80 wt% Ag and 20 wt% Ni, and the melt temperature was brought to 1750°C by high frequency melting. This molten metal was spouted from a ruby nozzle hole with a diameter of 3 mm at an argon back pressure of 1 Kg/cm ² , and the spouted flow was atomized with high-pressure argon gas at 70 Kg/cm ² to produce a rapidly solidified powder. The powder thus produced was annealed in the same manner as in Example 1. Examples 3 to 15 In Example 1, the types of metal A and metal B,
Example 1 except that the blending amount was as shown in Table 1.
In the same manner as above, a powdered conductive composite material was obtained,
Annealing was performed in the same manner as in Example 1. Comparative Example 1 After mixing Ag powder and Ni powder of 350 mesh or less in the ratio shown in Table 1, this powder was mixed with 400 mesh
℃ mold, molded at 10 tons/cm ² , and sintered at 850℃ for 3 hours in an argon atmosphere. Comparative Examples 2 to 5 In Example 1, the types of metal (A) and metal (B),
Example 1 except that the blending amount was as shown in Table 1.
In the same manner as above, a powdered conductive composite material was obtained,
Annealing was performed in the same manner as in Example 1. The hardness of the annealed powders and sintered materials obtained in the above examples and comparative examples was measured using a micro-Vickers hardness meter. A load of 100 g was applied for 15 seconds. The results are shown in Table 1.

〔Effect of the invention〕

As described above, the conductive composite material according to the present invention is composed of a matrix metal (A) containing a metal (B) that separates into two phases from the metal (A), and has a particle size of 0.01 to 1 μm.
One or more types of particles m are dispersed, and metal
Metal (B) is 0.5 to 20% of the total weight of (A) and metal (B)
%, so the hardness is high and the stickiness is low.
It is less abrasive and less deformed at high temperatures. As seen above, the method for producing a conductive composite material according to the present invention includes a metal (A) and a metal (B) that separates into two phases from this, and the total weight of the metal (A) and metal (B) is On the other hand, by rapidly cooling and solidifying a molten metal containing 0.5 to 20% metal (B), one or more particles of metal (B) with a particle size of 0.01 to 1 μm are dispersed in metal (A). In addition, the conductive composite material as described above can be easily produced because the metal (B) is 0.5 to 20% of the total weight of the metal (A) and the metal (B). be able to.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are micrographs of the metal structure, with Figure 1 being of one example, and Figure 2 being of the second example.
The figures are of a comparative example, FIG. 3 is a conventional example, FIG. 4 is a sectional view of an example of an apparatus used in the rotating liquid spray method, and FIG. 5 is a perspective view thereof.

Claims (1)

[Scope of Claims] 1. In the matrix metal (A), one or more particles having a particle size of 0.01 to 1 μm made of a metal (B) that separates into two phases from the metal (A) are dispersed, and (A) and metal (B)
A conductive composite material in which metal (B) is 0.5 to 20% based on the total weight of 2 Metal (A) is Ag, metal (B) is Ni, Cr, Fe,
The conductive composite material according to claim 1, which is at least one member selected from the group consisting of Co, Si, Rh, and V. 3. The conductive composite material according to claim 1, wherein the metal (A) is Au, and the metal (B) is at least one selected from the group consisting of Ge, Si, Sb, and Rh. 4. The conductive composite material according to claim 1, wherein the metal (A) is Cu and the metal (B) is Fe. 5 Contains metal (A) and metal (B) that separates into two phases from it, and the metal is
By rapidly solidifying a molten metal containing (B) at a ratio of 0.5 to 20%, one or more particles of metal (B) with a particle size of 0.01 to 1 μm are dispersed in metal (A), and , A method for producing a conductive composite material in which the content of metal (B) is 0.5 to 20% based on the total weight of metal (A) and metal (B). 6 Metal (A) is Ag, metal (B) is Ni, Cr, Fe,
The method for producing a conductive composite material according to claim 5, which is at least one member selected from the group consisting of Co, Si, Rh, and V. 7. The conductive composite material according to claim 5, wherein the metal (A) is Au and the metal (B) is at least one selected from the group consisting of Ge, Si, Sb and Rh. Manufacturing method. 8. The method for producing a conductive composite material according to claim 5, wherein the metal (A) is Cu and the metal (B) is Fe.