JPH09296234A - Production of alumina dispersion strengthened copper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce alumina dispersion strengthened copper where internal oxidation proceeds to the vicinity of the center of alloy powder and excellent strength, heat resistance, and electric conductivity are provided. SOLUTION: An alloy powder 1, having a composition consisting of Al and the balance Cu, and an oxidizing agent 3 are mixed, and the resultant mixture is mixed and compressed by means of rods 5 of a rod mill. By this procedure, the alloy powder 1 and the oxidizing agent 3 are put between the rods 5 and compressed, by which a lamellar powder 7 in which the oxidizing agent 3 is provided between mutually pressure-bonded alloy powders 1 is formed. By repeating this step, the thickness of the alloy powder 1 is reduced and the thickness Y(μm) is regulated so that it satisfies 32.X<-8> >=Y>=20 (where X means the weight percentage of Al in the powder). When heat treatment is applied to this lamellar powder 9, oxidation of the alloy powder 1 takes place from the surface of the lamellar powder 9 and the contact part with the oxidizing agent 3 and proceeds inward. Because respectice layers of the alloy powder 1 become extremely thin, internal oxidation can be allowed to processed easily to the vicinity of the center of the alloy power 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing alumina-dispersion-strengthened copper in which alumina is dispersed in a copper matrix to improve mechanical strength.

[0002]

2. Description of the Related Art Conventionally, it has been considered to produce alumina dispersion strengthened copper by dispersing alumina (Al ₂ O ₃ ) in a copper (Cu) matrix. This alumina dispersion strengthened copper has excellent heat resistance, thermal conductivity, and conductivity, and is used for various purposes. For example, it is used for resistance welding electrodes, gas arc welding contact tips and nozzles, molds, brazing lead wires, and the like.

Further, this kind of alumina dispersion strengthened copper is manufactured as follows. First, an alloy containing a predetermined amount of Al and the rest being Cu is pulverized by an atomizing method or the like, and the alloy powder is stirred and oxidized while being heated in the atmosphere. Then, Al on the surface of the alloy powder is oxidized and Al
₂ O ₃ is formed. Although also Cu alloy powder surface is oxidized to form a copper oxide (Cu ₂ O), the Cu ₂ O is C
Al having a stronger ionization tendency than u is oxidized to form Al ₂ O ₃ inside the alloy powder. This is called internal oxidation. In this way, alumina dispersion strengthened copper having Al ₂ O ₃ dispersed therein is also formed inside the alloy powder.

[0004]

However, this internal oxidation occurs only up to a certain depth range from the surface of the alloy powder. Therefore, if the grain size of the alloy powder is large, the Cu-Al alloy remains near the center thereof. In this part, A
Since l is a solid solution in Cu, the conductivity is low, and Al is Al
_Since it is not converted to ₂ O ₃ , it is inferior in strength and heat resistance.
It is known that the strength is improved by increasing the amount of Al, but as the amount of Al is increased, a large amount of oxygen is consumed on the surface of the alloy powder, and the internal oxidation does not proceed to the deep portion. Therefore, the sufficient effect cannot be obtained only by increasing the amount of Al. Further, if the grain size of the alloy powder is reduced, internal oxidation progresses to the vicinity of the center of the alloy powder, but there is a technical and cost limit in reducing the grain size.

Therefore, the present invention has been made for the purpose of easily producing alumina-dispersion-strengthened copper having excellent strength, heat resistance, and conductivity due to the progress of internal oxidation near the center of the alloy powder.

[0006]

Means for Solving the Problems and Effects of the Invention The invention as set forth in claim 1 made in order to achieve the above object,
By mixing an alloy powder containing 0.05 to 1.8% by weight of Al with the balance being Cu and an oxidizing agent to form a mixed powder, and mechanically mixing and compressing the mixed powder with a pulverizer,
It is characterized in that 97% or more of the powder is made into a layered powder satisfying the following conditions (1) and (2), and then the layered powder is subjected to a heat treatment to oxidize Al in the layered powder. The gist is the method for producing alumina dispersion strengthened copper.

(1) It has a structure in which flattened alloy powders are layered and an oxidizer is arranged between the layers. (2) The thickness Y (μm) of each layer of the layered powder satisfies the following equation. 32 · X ^−0.8 ≧ Y ≧ 20 However, X: Al in the powder
In the present invention thus constituted, the alloy powder and the oxidizer are mixed, and the mixed powder is mechanically mixed and compressed by a pulverizer. By this step, the mixed powder becomes a structure (layered powder) in which the flattened alloy powders are layered and the oxidizing agent is disposed between the layers. In such a structure, the alloy powder is in the form of a thin layer, and during the heat treatment, Al is oxidized from the contact portion with the oxidant arranged between the layers. Therefore, internal oxidation can be advanced to the center without reducing the grain size of the alloy powder as a raw material. Therefore, alumina dispersion strengthened copper having excellent strength, heat resistance, and conductivity can be easily manufactured.

The grounds for limiting the above numerical values are as follows. Further, the range of the weight% Al (X) and the thickness (Y) of each layer of the layered powder, which is limited to the present invention, is illustrated in FIG. If the amount of Al is less than 0.05% by weight, the amount of Al ₂ O ₃ is small even if it is completely internally oxidized, and sufficient strength and heat resistance cannot be obtained. If it exceeds 1.8% by weight, oxygen is consumed by Al on the surface of the alloy particles, and internal oxidation hardly occurs. Therefore, the mixing and compression by the pulverizer must be performed until Y becomes smaller than the lower limit value of 20 (μm) of the expression (2) (see FIG. 2). In this case, the time required for mixing / compressing becomes long and the productivity decreases, and the oxidation proceeds excessively during mixing / compressing, so that Cu
_A large amount of ₂ O is formed and the alumina dispersion strengthened copper becomes brittle.

Thickness of layered powder Y: Y> 32 · X ^−0.8 (μ
m), internal oxidation does not proceed to the center of each layer.
Therefore, sufficient strength and heat resistance cannot be obtained. A above
In the range of 1 amount, if the mixture is mixed and compressed until Y = 20 (μm), the internal oxidation proceeds sufficiently to the center of each layer of the layered powder. Further, even if the mixing and compression are further performed, the productivity is unnecessarily reduced, and Cu ₂ O in the inside is excessively caused, so that the final product, alumina dispersion strengthened copper, is weakened.

Proportion of layered powder satisfying the conditions (1) and (2): When mixed and compressed by a pulverizer, the size of the layered powder produced varies, and about 3% remains large. Is. Therefore, it was decided that 97% of the layered powder should satisfy the above conditions. Moreover, if the layered powder of this degree satisfies the above conditions, the strength and heat resistance of the final product, alumina-dispersion-strengthened copper, can be sufficiently ensured.

According to a second aspect of the present invention, in addition to the constitution of the first aspect, the oxidizing agent is 0.05 to 1.8% by weight of A.
alloy powder containing 1 and the balance being Cu
It is characterized in that the surface is oxidized by stirring while heating at 0 to 400 ° C.

That is, in the present invention, a material having the same structure as the alloy powder as a raw material is used as the oxidizing agent. Therefore, in the present invention, the alloy powder used as the oxidizing agent also serves as the constituent material of the alumina dispersion strengthened copper. Therefore, in addition to the effect of the invention described in claim 1, it is possible to obtain the effect that the waste of the raw material can be eliminated and the inclusion of impurities in the alumina dispersion strengthened copper as the final product can be suppressed.

The invention according to claim 3 is 0.05 to 1.8.
By alloying an alloy powder containing Al by weight and a balance of Cu while heating at 300 to 400 ° C. in the air to oxidize the surface of the alloy powder and mechanically mix and compress the powder with a pulverizer. , 97% or more of the following powder (1),
The gist is a method for producing alumina-dispersion-strengthened copper, characterized in that a layered powder satisfying the condition (2) is obtained, and then the layered powder is subjected to a heat treatment to oxidize Al in the layered powder.

(1) It has a structure in which flattened alloy powders are layered. (2) The thickness Y (μm) of each layer of the layered powder satisfies the following equation. 32 · X ^−0.8 ≧ Y ≧ 20 However, X: Al in the powder
That is, in the present invention, by oxidizing the surface of the alloy powder used as a raw material, the oxidized portion of the surface is used instead of the oxidizing agent (described in claims 1 and 2). Therefore, the same effects as those of the inventions according to claims 1 and 2 can be obtained, and since it is not necessary to individually handle the alloy powder and the oxidizing agent, it is possible to more easily manufacture the alumina dispersion strengthened copper. The effect is obtained. Therefore, the productivity can be greatly improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a process of producing alumina dispersion strengthened copper by a production method to which the present invention is applied, in particular,
It is explanatory drawing which represents typically the process until the layered powder 9 is formed.

As illustrated in FIG. 1, in the present manufacturing method,
An alloy powder 1 containing 0.05 to 1.8% Al and the rest being Cu is mixed with an oxidizer 3, which is mixed and compressed by a pulverizer (here, a rod mill). Then, the alloy powder 1 and the oxidizer 3 are sandwiched between the rods 5 and compressed, and for example, as illustrated in the drawing, the layered powder in which the oxidizer 3 is disposed between the alloy powders 1 pressed against each other. 7 is formed. If you repeat this crushing process many times,
The layer of the alloy powder 1 becomes thin, and the layered powder 9 has a thickness Y (μm) satisfying the following expression.

32 · X ^−0.8 ≧ Y ≧ 20 where X:
% By weight of Al in the powder This pulverizing step is executed until such layered powder 9 is formed in the alloy powder 1 covering 97% or more of the whole. As the crusher, various crushers can be used as long as they mechanically mix and compress. For example, when a ball mill is used, the rod 5 in FIG. 1 is replaced with a ball, and other operations are similar.

In the layered powder 9, a large number of layers of the alloy powder 1 are generally laminated, and the oxidizer 3 is arranged between the layers of the alloy powder 1. When heat treatment is applied to the layered powder 9, Al in the alloy powder 1 is oxidized. This oxidation reaction is a layered powder 9
Of the alloy powder 1 and the contact portion with the oxidizer 3, and progresses to the inside of the alloy powder 1. Each layer of the alloy powder 1 is extremely thin as described above. Therefore, internal oxidation can be advanced to the vicinity of the center without reducing the grain size of the alloy powder 1 as a raw material.

Further, according to the present manufacturing method, the following effects can be obtained by the above numerical limitation. . Since Y ≦ 32 · X ^−0.8 (μm) and the alloy powder 1 contains 0.05 wt% or more of Al, the internal oxidation is sufficiently advanced to the center of the alloy powder 1 and the alloy is A sufficient amount of Al ₂ O ₃ is formed in the powder 1.
Therefore, the alumina dispersion strengthened copper having sufficient strength, heat resistance and conductivity can be manufactured. . Since Y ≧ 20, the working time of the pulverization step can be sufficiently shortened, productivity is improved, and Cu ₂ O is formed in a large amount to prevent the alumina dispersion strengthened copper from becoming brittle. be able to. Further, since the weight% of Al is set to 1.8 or less, even if Y ≧ 20, internal oxidation can be performed up to the vicinity of the center of the alloy powder 1. . Since such layered powder 9 is formed for the alloy powder 1 covering 97% or more of the whole, the strength and heat resistance of the alumina dispersion strengthened copper can be sufficiently ensured. Further, since the crushing process is interrupted at this point, it is possible to prevent the productivity from being unnecessarily reduced and the alumina dispersion strengthened copper from being weakened.

Therefore, according to the present manufacturing method, the alumina dispersion strengthened copper having excellent strength, heat resistance and conductivity can be easily manufactured.

[0021]

[Examples] Next, a method for producing alumina dispersion strengthened copper to which the present invention was applied was specifically carried out and compared with a comparative example, which is a production method similar to the conventional one. First, the manufacturing method of each example and comparative example will be described. Example 1: Cu-0.10 wt% with a particle size of 297 μm or less
5% by mass of a mixture of Al alloy powder and the same alloy powder oxidized at 350 ° C. for 1 hour in the air while stirring (oxygen content 2% by weight) was mixed with a rod mill at a flow rate of 20 g / s. It was continuously crushed (mixed and compressed). By this treatment, 97% of the alloy powder has a layer thickness Y of 20 to 200 μm.
It became a layered powder of m. This layered powder was sealed in a rubber mold and CIP (cold isostatic press) with a water pressure of 196 MPa.
did. This CIP material can be made of oxygen-free copper (φ254mm × φ
234mm × 500mmL: outer diameter 254mm, inner diameter 234mm,
Enclosed in a length of 500 mm, the same below), 850 ° C x 3
After being heated and held for a period of time for internal oxidation, φ as a billet
It was hot extruded to 28 mm and drawn into a 16 mm diameter rod.
The amount of Al ₂ O _{3 in} this alumina dispersion strengthened copper part is 0.2% by weight.
Met.

Example 2: Cu-having a particle size of 297 μm or less
Cu in 0.10 wt% Al alloy powder _TwoO powder (particle size approx.
1 μm) is mixed by 0.6% by mass, and this is mixed in a rod mill.
And continuously pulverize (mix and compress) at a flow rate of 20 g / s
Was. By this treatment, 97% of the alloy powder has a layer thickness Y
Became a layered powder of 20 to 200 μm. This layered powder
Is an oxygen-free copper can (φ254 mm × φ234 mm × 500 mm
L), sealed by heating at 850 ° C for 3 hours and internally oxidized
After that, as a billet, hot extrude to φ28 mm and draw
Therefore, a rod with a diameter of 16 mm was prepared. This alumina dispersion strengthened copper part
Al_TwoO_ThreeThe amount was 0.2% by weight.

Example 3: Cu-having a particle size of 149 μm or less
0.3% by weight of Al alloy powder and Cu ₂ O powder (particle size of about 1μ
m) was mixed with 3%, and this was continuously pulverized (mixed and compressed) by a rod mill at a flow rate of 20 g / s. By this treatment, 97% of the alloy powder has a layer thickness Y of 20 to 80 μm.
Became a layered powder of. This was placed on a copper dish and heated and kept in an Ar gas atmosphere at 850 ° C. for 3 hours to be internally oxidized, and further heated and kept at 700 ° C. for 1 hour in a hydrogen gas atmosphere to reduce Cu ₂ O on the surface of the layered powder. Since the layered powder was sintered by the heat treatment, the layered powder after the treatment was taken out from the copper dish and crushed with a rod mill. This powder was enclosed in a phosphor deoxidized copper can (φ254 mm × φ234 mm × 500 mmL), which was hot extruded to φ28 mm as a billet, and then drawn into a φ16 mm rod. The amount of Al ₂ O _{3 in} this alumina dispersion strengthened copper part was 0.7% by weight.

Example 4: Cu-having a particle size of 149 μm or less
0.3 wt% Al alloy powder was oxidized at 350 ° C. for 1 hour while stirring in the air, and 20 g /
It was continuously pulverized (mixed and compressed) at a flow rate of s. By this treatment, 97% of the alloy powder has a layer thickness Y of 20 to 8
It became a layered powder of 0 μm. This was placed on a copper dish and heated and kept in an Ar gas atmosphere at 850 ° C. for 3 hours to be internally oxidized, and further heated and kept at 700 ° C. for 1 hour in a hydrogen gas atmosphere to reduce Cu ₂ O on the surface of the layered powder. Since the layered powder was sintered by the heat treatment, the layered powder after the treatment was taken out from the copper dish and crushed with a rod mill. This powder was enclosed in an oxygen-free copper can (φ254 mm × φ234 mm × 500 mmL), which was used as a billet to hot extrude to φ28 mm.
A 16 mm diameter rod was drawn by drawing. The amount of Al ₂ O _{3 in} this alumina dispersion strengthened copper part was 0.7% by weight.

Example 5: Cu-having a particle size of 149 μm or less
1.4% by weight Al alloy powder in air at 400 ° C for 1 hour
It was oxidized while being mixed and crushed with a ball mill. this
By the treatment, 97% of the alloy powder has a layer thickness Y of 20 to
It became a layered powder of 24 μm. Place this on a copper plate, Ar gas
Internal oxidation by heating at 880 ℃ for 2 hours
And hold at 700 ° C for 30 minutes in a hydrogen gas atmosphere.
And Cu on the surface of layered powder _TwoO 2 was reduced. By heat treatment
Since the layered powder was sintered, place the treated layered powder in a copper dish.
It was crushed with a rod mill. This powder is oxygen free copper
Enclosed in a can (φ254mm × φ234mm × 500mmL)
After hot extruding this into a billet of φ28 mm,
A 16 mm diameter rod was drawn by drawing. This alumina dispersion strengthening
Al of copper part _TwoO_ThreeThe amount was 2.3% by weight.

Comparative Example 1: Cu-having a particle size of 297 μm or less
The same alloy powder is added to 0.10 wt% Al alloy powder.
A mixture obtained by mixing 5% by mass of a substance (oxygen amount: 2% by weight), which was oxidized while stirring in the air at 1 ° C. for 1 hour, sealed this powder in a rubber mold and CIP was performed at a water pressure of 196 MPa. This CIP
Oxygen-free copper can (φ254mm × φ234mm × 500)
mmL), heated and held at 850 ° C. for 3 hours for internal oxidation, and then hot extruded to a diameter of 28 mm as a billet and drawn into a diameter of 16 mm.

Comparative Example 2: Cu-having a particle size of 297 μm or less
Cu in 0.10 wt% Al alloy powder _TwoO powder (particle size approx.
1 μm) was mixed in an amount of 0.6% by mass. This powder is oxygen free
Sealed in a copper can (φ254 mm × φ234 mm × 500 mmL)
Then, it was heated and held at 850 ° C. for 3 hours for internal oxidation.
After that, as a billet, hot extruding to φ28 mm and drawing
A φ16 mm rod was used.

Comparative Example 3: Cu-having a particle size of 149 μm or less
0.3% by weight of Al alloy powder and Cu ₂ O powder (particle size of about 1μ
m) was mixed in 3%. This was placed on a copper dish and heated and held in an Ar gas atmosphere at 850 ° C. for 3 hours for internal oxidation, and further heated and held at 700 ° C. for 1 hour in a hydrogen gas atmosphere to reduce Cu ₂ O on the powder surface. Since the powder was sintered by the heat treatment, the powder after treatment was taken out from the copper dish and crushed with a rod mill. Add this powder to a phosphor deoxidized copper can (φ254 mm x
(φ234 mm × 500 mm L), and this was used as a billet to hot extrude to φ28 mm, and then drawn into a φ16 mm bar.

Comparative Example 4: Cu-having a particle size of 149 μm or less
The 0.3 wt% Al alloy powder was oxidized while being stirred in the air at 350 ° C. for 1 hour. This is placed on a copper dish and heated and held in an Ar gas atmosphere at 850 ° C. for 3 hours for internal oxidation,
Further, it was heated and held at 700 ° C. for 1 hour in a hydrogen gas atmosphere to reduce Cu ₂ O on the powder surface. Since the powder was sintered by the heat treatment, the powder after treatment was taken out from the copper dish and crushed with a rod mill. Oxygen-free copper cans (φ254
mm × φ234 mm × 500 mmL), and using this as a billet, hot extruding to φ28 mm, then drawing to φ16
It was a mm stick.

Comparative Example 5: Cu-having a particle size of 149 μm or less
The 1.4 wt% Al alloy powder was oxidized in the atmosphere at 400 ° C. for 1 hour. Place this on a copper plate and place it in an Ar gas atmosphere for 8
The mixture was heated and maintained at 80 ° C. for 2 hours to be internally oxidized, and further heated and kept at 700 ° C. for 30 minutes in a hydrogen gas atmosphere to reduce Cu ₂ O on the powder surface. Since the powder was sintered by the heat treatment, the powder after treatment was taken out from the copper dish and crushed with a rod mill. Oxygen-free copper cans (φ254mm × φ23)
4mm x 500mmL) and use this as a billet
After hot extrusion to 28 mm, it was drawn into a bar having a diameter of 16 mm.

That is, in Examples 1 to 5 and Comparative Examples 1 to 5, those having corresponding numbers have similar manufacturing methods, and are different in whether or not a pulverizing step is performed to form a layered powder. Comparative Example 6: A material powder having an Al content of 1.9 wt% in Example 5 was prepared.
The amount of l ₂ O ₃ was 2.4% by weight. As mentioned above, Al
_{The 2} O ₃ conversion rate was as low as 47%, the strength was low, and the solid solution Al remained, so the conductivity was also lowered. Next, Table 1 shows the characteristics (conductivity, tensile characteristics, hardness) of the bar materials manufactured in the respective examples and comparative examples.

[0032]

[Table 1]

However, the Al ₂ O ₃ conversion rate in Table 1 was measured as follows. When the powder that has been subjected to the heat treatment and before forming the rod is dissolved with an acid, only Al is dissolved and Al ₂
O ₃ does not dissolve. Therefore, atomic absorption analysis was performed on the solution, and the amount of Al that was not Al ₂ O ₃ was measured and calculated from the following equation.

[0034]

[Equation 1]

As shown in Table 1, it can be seen that each example has improved mechanical strength as compared with the corresponding comparative example. Further, although not shown in Table 1, it was found by a tensile test after hardness annealing, a hardness test, etc. that each example had improved heat resistance as compared with the corresponding comparative example. As described above, according to the manufacturing method of each of the above-described examples, it is possible to easily manufacture the alumina dispersion strengthened copper having excellent strength, heat resistance, and conductivity.

Furthermore, in Example 1, the same powder as the alloy powder as the raw material was oxidized and used as the oxidizer. For this reason, it is possible to eliminate waste of raw materials, suppress inclusion of impurities in the alumina dispersion-strengthened copper as the final product, and easily set the composition of the alumina dispersion-strengthened copper. Further, in Examples 4 and 5, the oxidized portion on the surface of the alloy powder as the raw material is used instead of the oxidizing agent. Therefore, it is not necessary to individually handle the alloy powder and the oxidizing agent, and the alumina dispersion strengthened copper can be manufactured more easily. Further, as in the first embodiment, it is possible to eliminate the waste of materials, suppress the mixing of impurities, and easily set the composition.

The present invention is not limited to the above embodiments, and can be carried out in various modes without departing from the gist of the present invention. For example, various oxidants other than the above can be used.
Numerical values such as quantity can be set to various values within the scope of the present invention.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a process until a layered powder is formed by a manufacturing method to which the present invention is applied.

FIG. 2 is an explanatory view showing the range of the present invention of the weight% of Al and the thickness of each layer of the layered powder.

[Explanation of symbols]

1 ... Alloy powder 3 ... Oxidizing agent 5 ... Rod
7, 9 ... Layered powder

Claims (3)

[Claims] 1. An alloy powder containing 0.05 to 1.8% by weight of Al and the balance being Cu, and an oxidizing agent are mixed into a mixed powder, and the mixed powder is mechanically mixed by a pulverizer. By compressing, 97% or more of the powder is made into a layered powder satisfying the following conditions (1) and (2), and then the layered powder is subjected to a heat treatment to oxidize Al in the layered powder. A method for producing an alumina dispersion strengthened copper characterized by the above. (1) It has a structure in which flattened alloy powders are layered and an oxidizer is disposed between the layers. (2) The thickness Y (μm) of each layer of the layered powder satisfies the following equation. 32 · X ^−0.8 ≧ Y ≧ 20 However, X: Al in the powder
Wt% of 2. The oxidant is 0.05 to 1.8% by weight.
2. The alumina dispersion strengthening according to claim 1, wherein the alloy powder containing Al and the balance being Cu is stirred in the air while being heated to 300 to 400 ° C. to oxidize the surface thereof. Copper manufacturing method. 3. An alloy powder containing 0.05 to 1.8% by weight of Al and the balance of Cu is 300 to 400 in air.
By stirring while heating to ℃ to oxidize the surface, by mechanically mixing and compressing the powder with a pulverizer,
97% or more of the powder is used as a layered powder that satisfies the following conditions (1) and (2), and then the layered powder is subjected to heat treatment to oxidize Al in the layered powder. Manufacturing method of alumina dispersion strengthened copper. (1) It has a structure in which flattened alloy powders are layered. (2) The thickness Y (μm) of each layer of the layered powder satisfies the following equation. 32 · X ^−0.8 ≧ Y ≧ 20 However, X: Al in the powder
Wt% of