JPS6187836A - Production of fiber reinforced metallic composite material - Google Patents

Abstract

PURPOSE:To develop a fiber reinforced metallic composite material which is equiv. in conductivity and sliding characteristic to Cu and has excellent wear resistance and the frictional characteristic to the other material to be slid by mixing SiC short fibers and Cu or Cu alloy powder at a specific ratio and heating and sintering the mixture. CONSTITUTION:The particles of pure copper, Cu-Sn alloy, etc. having 0.5-50 D/d which is the ratio of an average diameter D with respect to the average diameter (d) of the SiC short fibers are added to and mixed with the SiC short fibers which are the aggregate of the SiC short fibers having 0.1-50mu average diameter (d) and contg. <=5wt% the SiC particles which are incorporated therein and are not made into fibers in the stage of producing the fibers. The SiC short fibers and Cu particles are so mixed that the volume percentage of the SiC short fibers attains 0.5-25% when the total amt. of the SiC short fibers and Cu particles is made 100. Such mixture is sintered in a metallic mold under a high pressure at a high temp. by which the fiber reinforced metallic composite material consisting of the Cu, Sn alloy, etc. as the matrix and contg. the SiC short fibers as the reinforcing material is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a fiber-reinforced metal composite material, and more specifically, a fiber-reinforced composite material using silicon carbide short fibers as the reinforcing fibers and pure copper or copper alloy as the matrix metal. Pertains to a method for manufacturing metal composite materials.

BACKGROUND OF THE INVENTION Pure copper and copper alloys have excellent sliding properties and electrical conductivity, and are therefore prized as sliding materials and electrical contact materials. However, when conventionally known copper alloys are applied to sliding members used under harsh conditions,
Wear resistance and seizure resistance are often insufficient. In addition, various alloying elements are added to pure copper in order to improve the wear resistance of electrical contact materials. If added, there is a problem that the conductivity will decrease, and therefore it is very difficult to improve both the wear resistance and conductivity of electrical contact materials. In addition, particle dispersion strengthened copper alloys and precipitation strengthened copper alloys, in which hard particles are dispersed in copper alloys, are already known in order to improve the wear resistance and strength of copper alloys. However, these copper alloys have various problems such as being difficult to manufacture, having poor machinability, and increasing wear of the mating material.

In view of the above-mentioned problems with pure copper and copper alloys used as sliding materials and electrical contact materials, the inventors of the present application have developed various materials using silicon carbide short 5iren as reinforcing fibers and pure copper and copper alloys as matrix metals. As a result of manufacturing composite materials using the powder metallurgy method and conducting various experimental studies on these composite materials, we found that in order to improve the wear resistance of pure copper and copper alloys while suppressing the increase in the amount of wear of the mating material. must be maintained within a certain range consisting of the volume fraction of silicon carbide short fibers and the total amount of hard, non-fibrous particles generally contained in the aggregate of silicon carbide short fibers, and the silicon carbide short fibers in the matrix metal. In order to produce a homogeneous composite material in which short fibers are uniformly dispersed, the ratio of the average particle diameter of matrix metal particles to the average fiber diameter d of silicon carbide short fibers is D/
It has been found that d needs to be maintained within a predetermined range.

Purpose of the Invention The present invention is based on the knowledge obtained as a result of various experimental studies conducted by the inventors of the present application, and is a composite material comprising silicon carbide short fibers as reinforcing fibers and pure copper or a copper alloy as a matrix metal. , it is possible to produce a homogeneous composite material that has properties such as sliding properties and conductivity that are substantially equivalent to pure copper and copper alloys, and also has excellent wear resistance and friction properties against mating materials. The purpose is to provide a method.

Structure of the Invention According to the present invention, the above-mentioned object is to obtain the average M & miscellaneous diameter d=
Silicon carbide short fibers having a size of 0.1 to 50 μ and the total content of non-41-7 particles contained in the aggregate is 5 wt% or less, and metal powder such as pure copper powder or steel alloy powder. and the ratio D/d of the average particle diameter of the metal powder to the average fiber diameter d is 0.5 to 50.The total volume of the silicon carbide short fibers and the volume of the metal powder is 100. %, the volume fraction of silicon carbide short phase phase is 0.5 to 25%, and the mixture is heated to a high temperature to sinter the metal powder. achieved by.

Effects and Effects of the Invention According to the present invention, a metal powder such as pure copper or a copper alloy is mixed with silicon carbide short fibers, and the metal powder is sintered, so that the pure copper or copper alloy is converted into a silicon carbide 'Fall A'. The wear resistance of pure copper or copper alloy can be greatly improved, and the volume fraction of silicon carbide short fibers and non-fibrous particles generally contained in aggregates of silicon carbide short fibers can be improved significantly. Since the total amount is maintained within a predetermined range, the mating material is not worn excessively, and therefore a composite material can be obtained that is excellent in both its own wear resistance and its frictional properties against the mating material.

Further, according to the present invention, the average fiber diameter d of the silicon carbide short fibers
Since the ratio D/d of the average particle diameter of the metal powder to Homogeneous composite materials in which the silicon short-layer phase is uniformly dispersed can be produced.

Furthermore, according to the present invention, it is possible to select pure copper or a copper alloy as the matrix metal, which has far superior conductivity compared to conventional copper alloys for contact materials, and will be described in detail later. According to the results of experimental research conducted by the inventors of the present application, it is possible to ensure sufficient wear resistance even in a region where the volume fraction of silicon carbide short fibers is relatively small, and to maintain sufficient wear resistance against the mating material. Since it can be sufficiently reduced, it is possible to obtain a composite material with far superior wear resistance and frictional properties against mating materials, and high N4 conductivity, compared to conventional electrical contact materials.

Silicon carbide short fibers have the effect of improving wear resistance, improving strength,
It has excellent heat resistance and is therefore suitable for use as reinforcing fiber. However, due to the manufacturing method, the aggregate of silicon carbide short fibers contains non-fibrous particles (shot) of various sizes of about 5 to 5 Qwt%, and these non-fibrous particles are Since it has a particle size that is extremely large compared to the fiber diameter and has a hardness second only to diamond, it is possible to use a composite material whose reinforcing fibers are aggregates of short silicon carbide fibers containing such non-fibrous particles. 1 has very poor workability, causes excessive wear of the mating material that contacts and slides relative to it, and even causes scuffing to the mating material due to non-fibrous particles falling off from the matrix metal. This may cause abnormal wear such as Therefore, according to the present invention, in order to solve the above problems, the total amount of non-fibrous particles contained in a 4 mm silicon carbide aggregate is 5 wt% or less, preferably 3 wt% or less, more preferably 1 wt% or less. particles that have been experimentally confirmed to be particularly susceptible to abnormal wear, etc. The content of non-fibrous particles with a diameter of 150μ or more is 1wt% or less,
Preferably 0.6wt% or less, more preferably Q, 2w
Maintained below t%.

In addition, in order to make use of the excellent characteristics of silicon carbide short fibers and thereby produce a composite material that has excellent wear resistance and friction properties against mating materials, we have: According to the results, the tJj fiber diameter is 0.5 to 2.
For general silicon carbide short fibers with a fiber length of 20 μm5w+m and a fiber length of 0 μm, the volume fraction is 0.5 to 25
%, preferably 0.5 to 20%. If the volume percentage of silicon carbide short fibers is 0.5% or less, the wear resistance of the composite material is insufficient, and if the volume percentage of silicon carbide short fibers is 25% or more, the n-purity of the mating material is The amount increases and the wear resistance of the composite material decreases.

Furthermore, in order to homogenize the composite material when manufacturing fiber-reinforced metal composite materials by the powder metallurgy method, the results of experimental research conducted by the present inventors indicate that As explained in detail in Japanese Patent Application No. 1983 filed by the same person, it is necessary to uniformly mix the matrix metal powder and the reinforcing fibers, and the fiber diameter is 0.5 to 20μ. Length is 20μ~5111111
When a general carbide silica phase is used as the reinforcing U&fiber, the ratio D/d of the average particle size of the matrix metal powder to the average fiber diameter d is 0.5 to 50, preferably It is preferable that it is 0.5-30.

In the present invention, prior to the process of heating the mixture of metal powder and silica carbide layer phase to a high temperature to sinter the metal powder, the mixture is heated to a pressure of 2000 to 7000 itg, '♂. In the process of compressing or heating the mixture to a high temperature, it is preferable that the mixture is compressed at a pressure of about 50 to 500 kQ/am2, and the mixture is heated to a high temperature to form metal powder. In the sintering process,
The atmosphere is preferably set to a reducing atmosphere or an inert atmosphere (inert gas or vacuum).

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

Example 1 Silicon carbide fiber manufactured by Nippon Carbon Co., Ltd. (average fiber 14
15μ in diameter) was treated so that the total amount of non-fibrous particles contained in the aggregate was 0.1 wt% or less, and the silicon carbide U & fibers were cut into 1 to 5 mm pieces. Next, the silicon carbide short fibers obtained in this way and Cu-10wt%Sn alloy powder (average particle size 80μ) were mixed for 30 minutes at a stirrer with agitation suppressed to reduce the volume of silicon carbide and the alloy powder. Mixtures were formed in which the volume percentages of silicon carbide short fibers were 0.5%, 10%, and 20%, with the total volume of silicon carbide short fibers being 100%. These mixtures were then spread into a 30m diameter
The mixture was introduced into a compression molding mold having a cylindrical cavity of 4000 kg/aa with a punch.
By pressurizing at a pressure of ', diameter 3Qn++n,
A cylindrical powder compact with a thickness of 15 mm was formed. Next, this compacted compact was heated to 7.70°C in decomposed ammonia gas.
The alloy powder was sintered by heating for 30 minutes to produce three types of composite materials 1 to A3 consisting of bronze composite reinforced with silica carbide phase.

Example 2 Silicon carbide voice force manufactured by Tokai Carbon Co., Ltd. (average fiber diameter 0.8μ, average fiber length 80μ) was treated so that the total amount of non-fibrous particles contained in the aggregate was 4wt%. was dispersed in acetone, electrolytic copper powder (average particle size 30μ, purity 99.8%) was added thereto, and mixed in a wet cross-wire system for 30 minutes. After kneading for 12 minutes, the mixture was air-dried in the air to form a mixture of silicon carbide voice and electrolytic copper powder. Next, the mixture was heated to 900°C using a hot press method in a vacuum atmosphere, and in that state it was heated for 2
00 k (heated and pressurized at a pressure of 1/am' for 12 f 120 minutes), and then cooled the mixture to room temperature to form an M! composite reinforced with silicon carbide voice force. Cylindrical composite material B made of copper with a diameter of 5Qmm and a thickness of 20mm (volume ratio of silicon carbide voice force 10%)
was manufactured.

Comparative Example 1 B) Bronze was made by compacting and sintering only the same alloy powder as that used in Example 1 under the same conditions as in Example 1 above. A cylindrical body (comparative material C+) having a diameter of 301 mm and a thickness of 151 mm was manufactured.

Comparative Example 2 Silicon carbide g:i Made of bronze composite reinforced with silicon carbide short fibers under the same conditions as in Example 1 above, except that the volume ratio of the mechanical fibers was set to 30%. Composite materials (
Comparative material C2) was produced.

Comparative Example 3 Under the same conditions as in Example 2 above, except that silicon carbide voice force in which the total amount of non-fibrous particles contained in the aggregate of silicon carbide voice force was Swt% was used. A composite material (comparative material Cs) made of pure copper reinforced with silicon carbide voice force was manufactured.

Comparative Example 4 Silicon carbide voice force manufactured by Tokai Carbon Co., Ltd. (average fiber diameter 0.8μ, average fiber length 80μ) was treated so that the total amount of non-fibrous particles contained in the aggregate was 4 wt% or less, Disperse this in acetone, add atomized copper powder (average particle size 110μ, purity 99.7%), mix this in a wet mixer for 30 minutes, and let it air dry to create a silicon carbide voice. and atomized copper powder. Next, this heated mixture was hot-pressed under the same conditions as in Example 2 above to produce a product made of pure copper composite-reinforced with silicon carbide and a volume percentage of silicon carbide of 10%. Composite material (comparative material C4
) was manufactured.

Comparative Example 5 Silicon carbide fiber manufactured by AVCO (average fiber diameter 140μ)
was cut into 1-5 mm pieces, and the volume ratio of silicon carbide short fibers was 1.
The sample was weighed and mixed with Qu-10wt%Sn alloy powder (average particle size 80μ) using a stirring crystallizer for 30 minutes. The mixture thus formed was molded into 400
By compressing at a pressure of 0 k (+/cn2), a cylindrical powder compact with a direct thickness of 3Q mm and a thickness of 15 mm was formed.The compact was then heated to 770°C in an ammonia decomposition gas. The alloy powder was sintered by heating for 30 minutes, thereby producing a composite material (comparative material C5) made of +4 copper reinforced with silicon carbide short fibers.

The composite material and the bronze sintered material (comparative material C1) produced as described above are summarized in Table 1 below.

Go - ff of each composite material and bronze sintered material manufactured as described above
1l! F! A In order to test the abrasion characteristics, 6X 10X 12n were used for each material so that the surface perpendicular to the compression direction was the test surface.
Cut out the u+ block test pieces, and LFWI! each block test piece sequentially! Set it in the N abrasion tester and bring it into contact with the outer circumferential surface of a cylindrical test piece made of bearing uA (J■S standard 5UJ2), which is the mating material. While supplying motor oil 5W-30>, load 60kqf, sliding speed 0, 3ff1lll
A sliding wear test was conducted in which the cylindrical test piece was rotated at /sec for 1 hour. The results of this wear test are shown in the attached figure.

In the attached figure, the upper half shows the wear amount of the block test piece (
The lower half represents the wear amount (wear area ffima>) of the cylindrical test piece that is the mating member.

From the attached diagram, the composite material according to the present invention is made by adding silicon carbide short fibers at a volume percentage of 0.5 wt%, iQwt%, and 20 wt% to bronze (comparative material C+), which is generally used as a material for sintered oil-impregnated bearings. (A+~△ri) is comparative material CI
It can be seen that the abrasion resistance of the composite material is far superior to that of the composite material, and as the volume fraction of silicon carbide short fibers increases, the abrasion resistance of the composite material improves. Furthermore, the amount of wear on the cylindrical test piece for composite materials A+ to A3 is substantially the same as the wear m on the cylindrical test piece for comparison material CI, and therefore, these composite materials also have excellent frictional properties against the mating material. I understand that there is. In addition, although the matrix metal of composite material B is pure copper, the amount of wear on itself is slightly larger than that of composite material A2, and the amount of wear on the other material is also compared with that of @C+ and composite materials A+~△3. equivalent and therefore its own 11
iII! i! It can be seen that it has excellent wear resistance and friction characteristics against the mating material.

On the other hand, in comparison material C2, in which the volume fraction of silicon carbide is 30%, the wear interval of the block test piece is small, but the wear amount of the cylindrical test piece is less than that of comparative material C1 and composite material A+~
It is about 20 times as large as A3 and B, which indicates that the friction characteristics against the mating material are inferior. This is considered to be due to the high aggressiveness of silicon carbide IIN to the mating material due to its high volume fraction. In addition, in comparison material C3 in which the total amount of non-fibrous particles contained in the aggregate of silicon carbide short fibers was 8 wt%, the amount of wear on the block test piece was greater than that of either of the composite materials of Examples 1 and 2. In addition, the amount of wear on the cylindrical test piece was even greater than that of comparative material C2.
Therefore, it can be seen that it is inferior to the composite materials of Examples 1 and 2 both in terms of its own W resistance: wear resistance and friction characteristics against the mating material. This is considered to be because the non-fibrous particles fell off from the matrix metal during the friction wear test, and the non-fibrous particles increased the amount of wear on both the block test piece and the cylindrical test piece.

In comparative material C4, in which the ratio D/d of the average particle diameter of the copper powder to the average fiber diameter d of the reinforcing fibers was 137.5, both the worn end of the block test piece and the wear amount of the cylindrical test piece were This value is high, and it can therefore be seen that comparative material C4 is inferior in both its own wear resistance and its frictional properties against the mating material. When the cross sections of the composite materials of Examples 1 and 2 and comparative material C4 were observed under a microscope, it was found that in the composite materials of Examples 1 and 2, the silicon carbide short fibers were uniformly dispersed. In comparison material C4, there are regions where the volume fraction of silicon carbide voice force is high and regions where it is low, and the amount of wear is large in the region where the volume fraction of silicon carbide whiskers is low, and the volume fraction of silicon carbide voice force is large. It is believed that the region with high abrasion increased the wear of the mating material, which caused the wear edges of both the block specimen and the cylindrical specimen to have relatively high values.

In comparison material C5, which was compositely reinforced with carbide silica fibers with an average U and minor diameter of 110μ, the amount of wear on the block test piece was relatively small, but the amount of wear on the cylindrical test piece was relatively high. It can be seen that the friction characteristics against the mating material are inferior. This is thought to be due to the excessive wear of the mating material by the short silicon carbide fibers having a large mechanical diameter.

Naomi/II The composite materials of Examples 1 and 2 are made of copper alloys (e.g. Cu-4Qwt%Zn) which are used as electrical contact materials.
It was confirmed that it is also more conductive than other materials (such as).

From the above explanation, according to the present invention, there is provided a composite material made of pure copper or copper alloy composite reinforced with silicon carbide short fibers, which has sliding properties and conductivity substantially equivalent to pure copper and copper alloy. It will be appreciated that a homogeneous composite material can be produced which has excellent wear resistance on its own and also has excellent frictional properties against mating materials.

Although the present invention has been described in detail above in connection with the experimental research conducted by the inventors of the present invention, the present invention is not limited to these examples, and any invention within the scope of the present invention. It will be clear to those skilled in the art that embodiments of the scale are possible.

[Brief explanation of the drawing]

The attached figures are graphs showing the results of friction and wear tests on various composite materials manufactured in Examples and Comparative Examples of the method for manufacturing fiber-reinforced metal composite materials according to the present invention.

Claims (1)

[Claims] Silicon carbide short fibers having an average fiber diameter d = 0.1 to 50 μ and the total content of non-fibrous particles contained in the aggregate is 5 wt% or less, and pure copper powder or copper alloy. The metal powder is a powder, and the ratio D/d of the average particle diameter D of the metal powder to the average fiber diameter d is 0.5 to 50.
is mixed with a metal powder such that the volume percentage of the silicon carbide short fibers is 0.5 to 25% when the sum of the volume of the silicon carbide short fibers and the volume of the metal powder is 100%, and the mixture is heated to a high temperature. A method for producing a fiber-reinforced metal composite material, which comprises heating the metal powder to a temperature to sinter the metal powder.