JPH04147933A - Contact material and its production - Google Patents

Abstract

PURPOSE:To obtain an Ag-Ni electrical contact material excellent in deposition resistance by sintering the composite grain of Ag and Ni, prepared by containing with Ni the surface of Ag grain containing Ni inside in the form of particle, fiber, etc. CONSTITUTION:Ag grains and Ni grains are charged to a rotary drum of a high shearing type mill as a mechanical compounding treatment apparatus, and this drum is rotated at high speed. as the Ag grain, a pure Ag grain 1 or an Ag grain, which contains Ni particles of <=0.5mum average particle diameter by 1-6% or in which fibrous Ni of 1mum average diameter or strip-like Ni of <=1mum average width is orientationally dispersed and Ni particles of <0.5mum average particle diameter are incorporated, if necessary, into the spaces among the above Ni fibers or strip-like bodies, is used. By mechanical compounding treatment, Ni layer 3 is formed around respective Ag grains 1, 1' mentioned above and Ag-Ni composite grains containing 6-20%, in total, of Ni are formed. These composite grains are compacted, sintered, and wiredrawn, by which the Ag-Ni electrical contact material excellent in deposition resistance can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact material used for electrical contacts of switching devices such as relays, magneto switches, breakers, etc., and a method for manufacturing the same.

[Conventional technology and problems]

Ag-Ni based contact materials, which are Ag-based contact materials, have excellent wear resistance and workability. However, Ag-
The Ni-based contact material is the same Ag-based contact material.
Compared to Cd0-based contact materials and Ag-3nO□-based contact materials,
Since the welding resistance is not sufficient, the use tends to be limited to low to medium load applications, and improvement in the welding resistance is desired.

Conventionally, the above-mentioned Ag-Ni contact material has been manufactured in the following manner.

Ni particles are added to and mixed with separately manufactured Ag particles, and compression molded to obtain a molded body.Then, the molded body is subjected to a sintering process in which [firing-hot compression] is repeated two to three times. After the process and sintering, it is usually stretched in a stretching process. In the drawing process, the sintered body is usually hot extruded and then further wire drawn. The N1 particles are stretched in the drawing direction in the drawing process, and are in the form of fibers with an average diameter of about 5 μm, with the elongated direction facing the drawing direction in the contact material. After drawing the wire, cut it into short pieces and use the cross section perpendicular to the drawing direction as the contact surface. That is, Ni is oriented and dispersed in the Ag matrix in the form of fibers with an average diameter of 5 μm in a direction crossing the contact surface.

In order to improve the welding resistance, it is necessary to finely disperse Ni onto the contact surface without grooves. For example, if both Ag particles and Ni particles are made into fine particles with a particle size of 1 μm or less, the fine Ni particles should not be localized on the contact surface and be dispersed without grooves, but this is not actually the case. At the stage of mixing fine particles, the fine particles aggregate and become large secondary particles, resulting in a large amount of N.
This is because they will be dispersed as i particles.

It is also conceivable to obtain N4-containing Ag particles and Ni particles at the same time by spraying a melt obtained by melting the total amounts of Ag and Ni to be blended together, and then molding and sintering them. In this case, fine Ni particles are present in the Ag particles, but coarse Ni particles with a very large particle size are mixed in the obtained particles. Undissolved Ni in the Ag-N1 molten metal becomes coarse Ni particles and is mixed therein. These coarse Ni particles have good moldability and
This causes a decrease in sinterability and a deterioration in welding resistance. The solid solubility limit of Ni in Ag in the molten metal is about 6 ivt%, so if the amount of Ni in the molten metal is 6st% or less, coarse N
Although the mixture of i-particles is eliminated, in this case, however, it is difficult to ensure a sufficient amount of Ni for the AgNi-based contact material.

[Problem to be solved by the invention]

In view of the above circumstances, this invention provides an excellent A
An object of the present invention is to provide a g-Ni-based contact material and a method for manufacturing the same.

[Means to solve the problem]

In order to solve the above problem, the contact material according to claim 1.2 is made of a sintered body of Ag particles whose surface is covered with a Ni layer, and the contact material according to claim 2 further includes Ag particles. is a particle in which Ni fine particles are dispersed.

Further, the contact material according to claim 3.4 has N in the Ag base material.
The contact material according to claim 4 has a structure in which i is oriented and dispersed in a fibrous shape with an average diameter of 1 μm or a strip shape with an average width of less than 11 in a direction crossing the contact surface, and It has a structure in which Ni fine particles having a particle size of 0.5 μm or less are dispersed between Ni0 particles.

The total Ni content in the contact material of this invention is usually 6 to 20 wt% (the entire contact material is 100 wt%).
t%).

In order to solve the above-mentioned problems, in the method for manufacturing a contact material according to claims 6 to 12, composite particles obtained by compounding Ag particles and Ni particles by mechanical compounding treatment are sintered. For example, as in claim 7, N1
An example is a form in which Fi covers the surface of the Ag particles.

The Ag particles to be subjected to the mechanical composite treatment are not limited to pure Ag particles, but may also be Ag particles in which Ni fine particles are dispersed, as in claim 8, and furthermore, as in claim 9, It may be an Ag particle in which a grain boundary exists inside the Ag particle and composite Ni exists in the grain boundary. Ni
In the case of Ag particles in which fine particles are dispersed, as in claim 10, the amount of Ni fine particles is 1 to 6 wt% (the whole particle is 100% by weight).
wt%), and the average particle size of the Ni fine particles is preferably less than 1 μm.

The total Ni content in the resulting contact material is usually as defined in claim 1.
1, 6 to 20wt% (100w of the entire contact material)
t%).

For example, the composite particles are produced by using a device equipped with a rotatable drum and a fixing member having a curved surface facing the inner peripheral surface of the drum, and injecting Ag particles and Ni particles into the drum. It can be obtained by a mechanical compounding process in which both particles are compressed and sheared by rotating a drum in this state.

Hereinafter, the present invention will be specifically explained step by step starting from the manufacturing stage.

In the method for manufacturing a contact material of the present invention, first, Ag particles and Ni particles are composited by a mechanical composite treatment.
A molded body is made using Ni composite particles.

As the Ag particles for producing composite particles, pure Ag particles or particles in which Ni fine particles are dispersed in Ag are used. This A
The average particle diameter of g particles is usually about 0.01 to 500n. The average particle size of Ni particles for preparing composite particles is usually
It is about 0.01 to Ion, and if it is outside this range, it becomes difficult to perform appropriate compositing. Usually, Ni particles are used that are smaller than Ag particles. The particle size of the Ni particles is about 1/2 or less (more preferably 1/10 or less) of the particle size of the Ag particles.

In the case of Ag particles dispersed in Ni fine particles, if the average particle size of the Ni fine particles is 1 μ or more or the Ni content is less than 1% or 1t%, it is difficult to expect a sufficient Ag base surface strengthening effect.
If the Ni content exceeds 6 wt%, particle production becomes difficult. The Ag particles in which fine Ni particles are dispersed can be obtained by ultra-quenching a molten metal of Ni and Ag, but it is difficult to incorporate 5 wt % or more of Ni into a solid solution.

A suitable form of Ag-Ni compositing in composite particles is
These are the following two.

In the first form, as shown in FIGS. 1(a) and (b), the composite Ni3 forms N1Fi covering the surface of the pure Ag particles 1 or the Ag particles 1' in which fine Ni particles are dispersed. It is.

In the second form, as shown in FIG. 2, the Ni fine particle dispersed Ag particles 1' have grain boundaries, and the composite Ni3
' is present at the grain boundaries. It is desirable that Ni exists to the extent that it covers the grain boundaries.

Next, a processing device that performs mechanical composite processing of Ag particles and Ni particles will be explained. As a processing device, a high-speed, high-shear type mill as shown in FIG. 3 (for example, ■Ong mill for mechanofusion system manufactured by Hosokawa Micron) is used.

The processing device 20 in FIG. 3 includes a drum (cylindrical container) 21 that can be rotated at high speed by a motor (not shown), and a ceramic (for example, hard alumina) semi-circular container supported by a fixed arm 22 inside the drum 21. This is a configuration in which a cylindrical fixing member 23 is provided. The fixing member 23 is fixed with the curved surface 23a of the semi-cylindrical portion facing the inner surface 21a of the drum, and while the drum 21 is rotating, the curved surface 2 of the semi-cylindrical portion remains stationary.
The inner surface of the drum 21 moves in front of the drum 3a. The radius of curvature of this semi-cylindrical curved surface 23a is smaller than the radius of curvature of the inner surface 21 of the drum.

When performing the compounding process, Ag particles and Ni particles are put into the drum 21 (along with media release beads added as necessary), and the drum 21 is made into an inert gas atmosphere and the drum 21 is rotated at high speed. . Then, as shown in FIG. 4, the Ag particles and Ni particles are pressed against the drum inner surface 21a by centrifugal force, rotate together with the drum 21, and rotate in the front region (between A and B) of the semi-cylindrical curved surface 23a.
When the Ag particles and Ni particles are subjected to strong compressive force and shear force, they are combined with the generated heat. When using media beads (for example, zirconia beads with a particle size of about 1 fi), the Ni particles first adhere to the beads and then to the Ag particles. In this way, composite particles can be easily produced using commercially available processing equipment.

The rotation speed of the drum is approximately 500 to 2000 times/min. The distance d between the semi-cylindrical curved surface 23a and the drum inner surface 21a is
Usually, it is about 1 to 5n.

At the beginning of the process, the Ni particles 30, which were in a weak agglomerated state as shown in Fig. 5 (al), became primary particles as the drum 21 rotated, and then became Ag particles, as shown in Fig. As Ni particles adhere to the surface of 1 (1') and the treatment progresses,
As shown in FIG. 5(C), an ordered mixture state is formed in which the Ni particles 30 are regularly arranged. moreover,
As the treatment progresses, due to the effects of strong compressive force, shearing force, and generated heat, the composite Ni3 becomes A as shown in Figure 5(d).
A Ni layer is formed to cover the surface of the g particle 1 (1'). The processing time until the Ni layer is formed is usually about 15 to 70 minutes.

In the case of Ag particle 1' (Ag particle with Ni fine particle dispersion), the inventors found that if the process is continued further, composite Ni will enter the crystal grain boundary if it has appropriate grain boundaries. I am discovering that. In other words, as shown in FIG. 6(a), the composite Ni3 covering the surface of the Ag particle 1' causes the grain boundaries to slip and rotate, as shown in FIG. 6(b). As the process progresses, the sixth
As shown in Figure (C1), a state is reached in which composite Ni3' is uniformly dispersed along the grain boundaries and exists at the grain boundaries.The processing time to reach this state is usually about 60 to 120 minutes. Note that some of the composite Ni still remains on the surface of the Ag particles 1', and the treatment may be completed in a state where the composite Ni exists both on the surfaces of the Ag particles 1' and at the grain boundaries.A.
A suitable average grain size of the crystal grains of the g particles is about 2 to 50 m. The Ag particles 1' obtained by ultra-quenching (for example, atomization with water) a molten Ag containing Ni in an amount of 1 to 6 imt% have crystal grains with an average grain size of 5 to 30 nm.

On the other hand, in the case of pure Ag particle 1, as seen in FIGS. figure(
As shown in Q), a plurality of pure Ag particles 1 become a fusion product IO that incorporates Ni particles 30 (pecked together, and as shown in Fig. 7 tf), and finally a sufficient amount of Composite particles 1'' are granulated in which fine Ni particles 30 of
- Ni particles 30 of 51 or less are used.

Conventionally, Ag particles and Ni particles are mixed in a V-shaped mill before molding, but the particles are only stirred and mixed and are not composited.If you look at the mixing state in detail, the Ag particles and Ni particles are individually mixed. It is in a separated state.

The composite particles obtained as described above are pressure-molded to obtain a molded body.

Next, the molded body is sintered. In this sintering process,
Usually, the molded body is subjected to [firing-hot compression] two times.
A sintered body is formed by repeating the process ~3 times.

After sintering, the drawing process begins. In this drawing step, the sintered body is hot extruded and then wire drawn.

The contact material that has undergone the stretching process is shown in Figure 1 (in the case of using composite particles of Al, as shown in Figure 8, the Ni41 in the Ag matrix 4o exists in a state of being elongated in the drawing direction). Even when the composite particles shown in FIG. 1(b) are used, as shown in FIG. 11, Ni 41 exists in the Ag matrix 40 in a state of being elongated in the wire drawing direction, and the Ni fine particles 42 exist between them. It will be dispersed.

Stretching is usually performed so that the ratio of [cross-sectional area before stretching]/[cross-sectional area after stretching] is 150 or more.

After drawing the wire, it is cut into pieces in a direction perpendicular to the drawing direction, and the cut surfaces are used as contact surfaces. Usually, after cutting, rivets are applied to the electrical contacts 5 as shown in Fig. 9 or 12.
In the case of the contact material shown in Figure 8, which is made to be 0.50', Ag base 4
In the contact surface, Ni is oriented and dispersed in the form of fibers or bands in the direction crossing the contact surface (cut surface).
As shown in Figure 0, fibrous Ni is dot-like Ni41'
The strip-shaped Ni is exposed as linear Ni41''.

In the case of the contact material shown in FIG. 11, Ni is oriented and dispersed in the Ag base 40 in the form of fibers or bands in a direction crossing the contact surface (cut surface), and Ni fine particles are dispersed between them. , as shown in Figure 13, fibrous Ni
is exposed as a dot-like Ni41', and a band-like Ni41' is exposed.
is exposed as a linear Ni41'', and Ni
Fine particles 42 are showing their faces. Dot-like Ni41' and linear Ni41'' originally form a Ni layer on the surface of the Ag particle, and for this reason, they are divided microscopically, but macroscopically they are connected in a ring shape, as shown in Fig. 10.13. As shown in Figure 2, a mesh-like Ni portion appears on the contact surface.When a mesh-like Ni portion appears on the contact surface like this, it is difficult to improve welding resistance, wear resistance, etc. It is considered advantageous.

This is because it is presumed that damage to the Ag substrate can be prevented on the inside of each ring of Ni, and progress of deterioration of the contact surface can be suppressed.

The thinly torn part of the Ni layer covering the Ag particle surface is
It is stretched and becomes fibrous, and the parts that are not torn are stretched and become a band.

The diameter and width of fibrous or band-like Ni are determined by the thickness and degree of stretching of the Ni layer, but the average diameter is less than ln or 1.
Preferably, the average width is less than μ. Further, it is preferable that the Ni fine particles 42 have an average particle diameter of 0.5 tt* or less. The Ni fine particles 42 are previously dispersed within the Ag particles 1' as Ni fine particles having an average particle diameter of less than 1n. It is not necessary that both fibrous and band-like forms exist;
A state in which only one of the two is present may also be acceptable.

The contact material obtained by the manufacturing method of this invention is shown in FIG.
It goes without saying that the configuration is not limited to that shown in FIG.

For example, when composite particles 1'' are used, most of the Ni will be dispersed in the form of fibers.

[For production]

In the contact material according to claim 1, Ni is distributed in advance to each Ag particle in the form of a Ni layer covering the surface of the Ag particle, so that Ni is not localized and spreads between each Ag particle. Furthermore, the amount of Ni is not suppressed too low, and a sufficient amount of Ni is finely and disease-free dispersed in the Ag base material, improving welding resistance.

As in claim 2, when Ni fine particles are dispersed inside the Ag particles, the Ag between the Ni0 inserted in the form of a Ni layer
Since the base material is further strengthened with Ni fine particles, welding resistance is further improved.

In the contact material according to the third aspect, fine Ni in the form of dots with an average particle diameter of less than 1n or in the form of lines with an average width of less than 1n appears on the contact surface without any signs of illness, thereby improving the welding resistance.

In the case of claim 4, fine Ni in the form of
Since the Ag base between the two is further strengthened with Ni fine particles having an average particle size of 0.5n or less, the welding resistance is further improved.

When the total Ni content in the contact material is an appropriate amount of 6 to 20 wt% as in claim 5 (or claim 10), a significant Ni addition effect can be reliably achieved.

In the case of the manufacturing method according to claim 6, a sufficient amount of Ni is distributed in advance to each Ag particle by mechanical compounding treatment of Ag particles and Ni particles, and the resulting contact material has a sufficient amount of Ni. A large amount of Ni is present in a fine and healthy state without being localized, and as a result, the welding resistance is improved.

In the case of claim 7, the Ni layer on the surface of each Ag particle creates a sufficient amount and even Ni dispersion state. In the case of claim 8, the Ni fine particles pre-dispersed within the Ag particles further strengthen the Ag matrix. do.

In the case of claim 9, since the composite Ni is present at the grain boundaries of the Ag particles, Ni is dispersed more healthily, and it is expected that the welding resistance will be further improved.

As in claim 1O, the amount of Ni fine particles in the Ag particles is 1
6 wt% and the average particle size of the Ni fine particles is less than 1n, the reinforcing effect of the Ni fine particles is significant.

According to claim 12, an apparatus including a rotatable drum and a fixing member having a curved surface facing the inner peripheral surface of the drum is used, and the drum is rotated with Ag particles and Ni particles introduced into the drum. By compressing and shearing both particles, composite particles for producing Ag-Ni contact materials having excellent welding resistance can be easily obtained.

〔Example〕

The present invention will be explained in detail below. This invention is not limited to the following embodiments.

Example 1 First, Ag particles in which Ni fine particles were dispersed were obtained as follows. Ag and Ni are melted together in a high frequency furnace and 165
F+m at 0° C. was prepared, and water was atomized by jetting it out from a nozzle and using high-pressure water. The obtained Ag particles have an average particle size of 4Q, n, and a Ni content of 5.2 wt%.

These Ag particles and Ni particles with an average particle size of 1n were weighed so that the total Ni content was 10 wt%, and using the above-mentioned high-speed, high-shear mill, the inside of the drum was set to an Ar gas atmosphere and used as a medium with an average particle size of about 10%. Using 1mm zirconia beads, 300
The treatment was carried out for 0 seconds to obtain composite particles.

Figure 14 shows the appearance (particle structure) of the composite particles, and the particle cross section (
The metallographic structure is shown in Fig. 15.16. Figures 14 to 16 are photographs taken with a scanning electron microscope;
The figure is a secondary electron beam (SEM image) photograph, and FIG. 16 is a characteristic X-ray (N i Kα image) photograph. In particular, when looking at FIG. 16, it is clearly seen that the Ag particles have Ni fine particles having an average particle size of less than 111 m dispersed inside them, and a Ni layer formed by composite Ni is formed on the surface.

Next, the composite particles were press-molded (30 kgf/1 m) to obtain a molded body.

Then, baking at 850℃ for 2 hours at -420℃ and weighing 90kg.
The f/w hot compression was repeated three times to obtain a sintered body. In addition,
The first firing was performed in a vacuum atmosphere, and the second and third firings were performed in a nitrogen atmosphere.

Subsequently, the sintered compact was hot-extruded at a preheating temperature of 800° C. and a mold temperature of 420° C. to a diameter of 8 NM, and then further drawn to a diameter of 2 WM. A cross-sectional state of the wire-drawn contact material along the longitudinal direction is shown in FIGS. 17 and 18. Chapter 17.1
Figure 8 is a photograph taken with a scanning electron microscope.
The figure is a secondary electron beam (SEM image) photograph, and FIG. 18 is a characteristic X-ray (N i Kα image) photograph. From Figure 17.18,
It is clearly seen that the Ni layer portion on the surface of the Ag particle is elongated and thinned in the wire drawing direction, and a large number of Ni fine particles are dispersed therebetween. After wire drawing, it was cut into pieces in a direction perpendicular to the wire drawing direction and subjected to glue head processing to obtain glue head contacts for contact performance evaluation.

Example 2 A contact material was obtained in the same manner as in Example 1, except that the average particle size of the Ag particles was 380μ and the average particle size of the Ni particles was 0.02n.

The appearance (particle structure) of the composite particle is shown in FIG. 19, and the cross section (metallic structure) is shown in FIG. 20.21.

19 to 21 are photographs taken using a scanning electron microscope, FIGS. 19 and 20 are secondary electron beam (SEM image) photographs, and FIG. 21 is a characteristic X-ray (N i Kα image) photograph. In particular, when looking at FIG. 21, it is clearly seen that the Ag particles have Ni fine particles dispersed inside them, and a Ni layer formed of composite Ni is formed on the surface.

Example 3 The average particle size of Ag particles was 1O, and the Ni content was 3°1im.
t%, the average particle size of the Ni particles is 0.02x,
A contact material was obtained in the same manner as in Example 1, except that the total Ni content was 20 wt%.

Example 4 The average particle size of Ag particles is 200n, the average crystal grain size is IQ
n, the Ni content is 3.1 hot%, the average particle size of the Ni particles is 0.2 n, and the total Ni content is 15 w.
t%, and the decoding processing time is set to 62%.
A contact material was obtained in the same manner as in Example 1, except that the crystal grain boundaries were covered with composite Ni.

Example 5 - Pure Ag with an average particle size of 1 μm that does not contain Ni fine particles in Ag particles
Other than using Ni particles with an average particle size of 0.02- to make the total Ni content 6 wt%,
A contact material was obtained in the same manner as in Example 1.

Comparative Example 1 A contact material was obtained in the same manner as in Example 1, except that the Ag particles of Example 1 were used as they were without being combined with Ni to form a molded body.

Comparative Example 2 After obtaining a molded body by mixing electrolytic Ag particles with an average particle size of 45x and carbonyl Ni particles (powder) with an average particle size of 5n, a contact material was obtained in the same manner as in Example 1. Note that the Ni content is 10 wt%.

The rivet contacts of Examples 1 to 5 and Comparative Example 1.2 were examined for welding resistance and wear characteristics by ASTM tests (number of samples N=3). The test conditions are as follows.

The test results are shown in Table 1 Load: Resistance Load Voltage: 1oov Current = 40A Number of openings and closings: 50,000 times The high temperature hardness of the contact materials of Example 1 and Comparative Example 1 was measured. The measurement results are shown in FIG. 22. In addition, the average particle diameter or average width of fibrous or band-like Ni on the contact surface of the contact materials of Examples 1 to 5 and Comparative Example 2 was investigated,
Regarding Example 1.3.4, the average particle size of the Ni fine particles was also investigated.

As shown in Table 1, the contact materials of the examples have good abrasion resistance and have better welding resistance than those of the comparative examples.

As shown in FIG. 22, the contact material of Example 1 is the same as that of Comparative Example 1.
The high-temperature hardness is higher than that of the conventional steel, which is a measurement result that confirms the improvement in welding resistance.

The average particle diameter or average width of the fibrous or strip-like Ni on the contact surface was less than 1n in the contact material of Examples 1.3.4.5, and 3n in the contact material of Example 2. On the other hand, in the contact material of Comparative Example 2, it was 5p. In the contact material of the example, Ni is dispersed in a finer state, and these measurement results confirm that the welding resistance is improved. Note that the average particle size of the Ni fine particles in the contact material of Example 1.3.4 was 0.5 nm or less. Because there are no grooves between particles and quantitative restrictions on Ni content are relaxed, Ag has excellent adhesion resistance.
Ni contacts can be realized.

In the contact material according to the second aspect, the Ni fine particles predispersed inside the Ag particles completely strengthen the Ag base, so that the welding resistance is further improved.

In the contact material according to the third aspect, since the particle size and content of the Ni fine particles previously dispersed inside the Ag particles are appropriate, a remarkable reinforcing effect by the Ni fine particles is reliably exerted.

The contact material according to claim 4 is an Ag-N material with excellent welding resistance, since the dot-shaped or linear fine Ni particles and the Ni fine particles dispersed therebetween sufficiently strengthen the contact surface.
i-contact can be realized.

Since the contact material according to claim 5 has an appropriate total Ni content, the effect of Ni addition is significant.

In the method for manufacturing a contact material according to claims 6 to 12, a sufficient amount of Ni is distributed in advance to each Ag particle by mechanical compositing treatment, and a sufficient amount of Ni is applied to finely disease-free Ag particles. Since it is dispersed in the base material, an excellent Ag-Ni contact material with high welding resistance can be obtained.

In the case of the method described in claim 7, the composite Ni is distributed as a Ni layer on the surface of the Ag particles, thereby ensuring that a sufficient amount of Ni is finely and disease-free dispersed in the Ag matrix.

In the case of the method described in claim 8, the Ni fine particles previously dispersed inside the Ag particles thoroughly strengthen the Ag base, so that the welding resistance is further improved.

In the case of the method described in claim 9, since the composite Ni exists at the grain boundaries of the Ag particles, Ni is dispersed more healthily, and further improvement in welding resistance can be expected.

In the case of the method according to claim 10, since the particle size and content of the Ni fine particles previously dispersed inside the Ag particles are appropriate, the reinforcing effect of the Ni fine particles is significant and reliable.

In the case of the method according to claim 11, since the total Ni content is appropriate, the effect of Ni addition is significant.

The method according to claim 12 has the advantage that the composite particles necessary for making the contact material can be easily produced.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of an example of a composite particle used in the method of this invention, Fig. 2 is an explanatory diagram showing the internal state of an example of a composite particle used in the method of this invention, and Fig. 3 is FIG. 4 is a schematic sectional view showing the main parts of the apparatus for producing composite particles used in the method of this invention. FIG. 4 is an explanatory diagram showing the state of the apparatus during mechanical compositing processing. FIGS. 8 and 11 are explanatory diagrams showing the particle changes in the progression order as the composite processing progresses, and FIGS. 8 and 11 are explanatory diagrams showing the dispersion state of Ni in a cross section along the wire drawing direction of the contact material of the present invention. Figure, No. 9
10 and 13 are plan views showing the exposed state of Ni on the contact surface of the rivet contact, and FIGS. Figure 14 is an electron micrograph showing the particle structure of the composite particles of Example 1, Figure 15 and Figure 1.
6 is an electron micrograph showing the metal structure of a cross section of the composite particle, FIGS. 17 and 18 are electron micrographs showing the metal structure of a cross section of the contact material of Example 1, and FIG.
The figure is an electron micrograph showing the particle structure of the composite particles of Example 2, FIGS. 20 and 21 are electron micrographs showing the metal structure of the cross section of the same composite particles, and FIG. 2 is a graph showing the high temperature hardness characteristics of the contact material of Comparative Example 1. 1.1'...Ag particle, 1"...composite particle 2...
・Ni fine particles 3...Ni layer (composite Ni) 2
0... Mechanical composite processing device 21... Drum
21a...Drum inner surface 23...Fixing member
23a...Semi-cylindrical curved surface (curved surface) 30...Ni
Particles 40...Ag base material 41...(dispersion) N
i 42...Ni particle agent Patent attorney Takehiko Matsumoto Figure 2 Figure 3 Figure 6 Figure 7 (f) Figure 14 Qpm Figure 15. Fig. 18 -Helir Fig. 19 - 100μ melon Fig. 20 Section 21 l0Cs tiger

Claims (1)

[Claims] 1. A contact material made of a sintered body of Ag particles whose surface is covered with a Ni layer. 2. The contact material according to claim 1, wherein the Ag particles have Ni fine particles dispersed therein. 3 A contact material in which Ni is oriented and dispersed in the Ag base in the form of fibers with an average diameter of 1 μm or in the form of bands with an average width of less than 1 μm in a direction crossing the contact surface. 4 Average particle size of 0.5 μm between fibrous or band-like Ni
The contact material according to claim 3, wherein the following Ni fine particles are dispersed. 5. The contact material according to claim 1, wherein the total Ni content is 6 to 20 wt%. 6. A method for producing a contact material, which involves sintering composite particles obtained by compounding Ag particles and Ni particles by mechanical compounding treatment. 7. The method for manufacturing a contact material according to claim 6, wherein in the composite particles, the Ni layer covers the surfaces of the Ag particles. 8. The method for manufacturing a contact material according to claim 6 or 7, wherein Ag particles in which Ni fine particles are dispersed are used as the Ag particles. 9. The method for manufacturing a contact material according to claim 6, wherein the Ag particles have grain boundaries inside and Ni is present in the grain boundaries. 10. The method for manufacturing a contact material according to claim 8 or 9, wherein the amount of Ni fine particles in the Ag particles is 1 to 6 wt%, and the average particle size of the Ni fine particles is less than 1 μm. 11. Claims 6 to 1, wherein the total Ni amount is 6 to 20 wt%.
0. A method for manufacturing a contact material according to any one of items 0 to 0. 12 The mechanical compounding process uses a device equipped with a rotatable drum and a fixed member having a curved surface facing the inner peripheral surface of the drum, and rotates the drum with Ag particles and Ni particles placed in the drum. The method for producing a contact material according to any one of claims 6 to 11, which is carried out by subjecting both particles to compression and shearing.