KR101650173B1 - A manufacturing method of Cu-Carbon binded powder and powder manufactured thereby - Google Patents

Abstract

The present invention enables a part of the lubricant particles to act as an inter-particle binder (binder) of copper powder and graphite powder through a predetermined mixing process, thereby eliminating the segregation phenomenon of the mixed powder and improving the flowability and other physical properties A graphite powder and a lubricant powder are prepared, the copper powder, the graphite powder and the lubricant powder are simultaneously introduced into a mixer, primary mixing is performed for a predetermined period of time, , The primary mixed mixture is charged into a gravity-free mixer, and the mixture is mixed at a low temperature for a predetermined time while maintaining the first temperature in a zero-gravity mixer, so that a part of the lubricant powder is melted to form particles of the copper powder and particles And the mixture is mixed at a low speed while being lowered to a second temperature lower than the first temperature for a predetermined time in a zero-gravity mixer, Graphite bonding powder comprising a step of solidifying the particles of the copper powder and a part of the lubricant powder which are brought into contact with the particles of the graphite powder, and discharging the powder from the zero-gravity mixer.

Description

Technical Field The present invention relates to a method for producing a copper-carbon bond powder and a copper-carbon bond powder prepared using the same,

The present invention relates to a method for producing a copper-carbon bond powder and a copper-carbon bond powder produced using the copper-carbon bond powder. More particularly, the present invention relates to a method for producing a copper- Carbon bond powder or the like which acts as a binder (binder) to remove segregation of mixed powder and to improve flow properties and other physical properties.

The metal powder is used for manufacturing a metal product by charging the metal powder into a die having a predetermined shape, compressing it to form a green compact, taking out it, and sintering it. However, when various materials such as graphite and metal for alloying are added to and mixed with metal as a main material, the sizes, shapes and densities of the particles are different from each other in preparing the main material. Therefore, Thereby causing a phenomenon.

Particularly, in the case of a mixed powder containing graphite, due to lack of flowability of the graphite, the mixed powder is not filled up to the corner of the mold in the process of injection into the mold for the compaction step Problems such as product weight deviation occur. This is particularly a problem when filling is performed at high speed. Specifically, it affects powder properties such as external density and flowability, and further affects product characteristics such as strength and shrinkage rate deviation.

3.65 to 4.35% by weight of nickel (Ni), 1.38 to 1.62% by weight of copper (Cu), and 0.01% by weight of copper are disclosed in Korean Patent No. 1345982 (hereinafter, referred to as a method of manufacturing a mechanical component by powder metallurgy, 0.1 to 0.9% by weight of carbon (C) and 0.4 to 1.2% by weight of a lubricant are added to an iron alloy powder composed of molybdenum (Mo) 0.4 to 0.6% by weight and unavoidable impurities and residual iron (Fe) And mixing for 30 to 40 minutes.

KR 1345982 B

Conventional technique 1 segregates in the course of mixing raw material components, transferring mixed powder after the mixing process, or introducing the mixed powder into a subsequent process, thereby reducing the product dimensions in a later sintering process, There is a possibility that a problem of large single-center deviation (weight and dimensions, etc.) occurring in mass production may occur.

In order to solve the above problems, the present invention provides a method for producing a graphite powder, comprising the steps of: (i) preparing a copper powder, a graphite powder and a lubricant powder; (ii) simultaneously injecting the copper powder, the graphite powder and the lubricant powder into a mixer (Iii) performing a primary mixing for a predetermined period of time, (iv) introducing the primary mixed mixture into the non-gravity mixer in the step (iii), (v) Mixing the particles of the copper powder and the particles of the graphite powder by melting a part of the lubricant powder for a predetermined period of time while holding the graphite powder, and (vi) And a part of the lubricant powder which has been melted in the step (v) to couple the particles of the copper powder and the particles of the graphite powder is again solidified It proposes a method for producing a graphite powder bonded-phase, (vii) copper comprises a step for discharging the powder from the gravity-free mixer.

Also disclosed is a copper-graphite bond powder produced by a method for producing a copper-graphite bond powder.

Also, a green compact manufactured by using the copper-graphite binding powder produced by the manufacturing method of the present invention is proposed.

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a method of binding (bonding) particles having different specific gravity to each other, such as copper particles, graphite particles, alloy particles, and the like, Or the effect thereof can be minimized, the flowability is improved owing to the application of the lubricant, so that when the product is formed by the subsequent compaction or sintering process, the density of the product can be made uniform, And a third effect is that the product quality can be improved by generating a small weight and dimensional deviation even in a high-speed process application for mass production.

1 is an SEM image of powders according to Example 2 (lower row) and Comparative Example 2 (upper row) of the present invention.
2 is an SEM image of powder according to Example 3 (lower row) and Comparative Example 3 (upper row) of the present invention.
3 is an SEM image of powders according to Example 4 (lower row) and Comparative Example 4 (upper row) of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The copper-graphite binding powder produced according to the method for producing a copper-graphite binding powder of the present invention is characterized in that graphite particles float relative to copper particles due to the difference in density between copper and graphite particles, And the flowability is improved. The copper-graphite binding powder comprises a plurality of copper-graphite binding particles. That is, the copper-graphite binding powder is referred to as a powder comprising a plurality of copper-graphite binding particles. The copper-graphite binding particles include copper powder particles, graphite powder particles for improving lubricity after sintering, and a binder agent for binding the copper powder particles and the graphite powder particles

Hereinafter, each step of the method for producing the copper-graphite bonded powder of the present invention will be described in detail.

First, prepare copper powder, graphite powder and lubricant powder.

The copper powder may be prepared by a known method so as to have a predetermined purity and particle size. There is no particular limitation on the average particle size of the copper powder particles, but it is preferably in the range of 5 to 250 micrometers. Considering that the copper-graphite bonded powder of the present invention is used for manufacturing a slide member such as a magnetic core, a bearing, a bush, etc. through a compaction step of forming a product shape through pressurization and a subsequent sintering process , It should be considered that if the average particle size of the copper powder particles is too large, the size of the pores in the compaction process becomes large, and as a result, the density variation of the final product after sintering may become large. On the other hand, if the average particle size of the copper powder particles is too small as compared with the average particle size of the graphite powder particles, the segregation phenomenon due to the difference in density between the copper powder particles and the graphite powder particles may be increased.

The graphite powder may be prepared by a known method so as to have a predetermined particle size. The graphite powder particles function as a solid lubricant. Especially when the copper-graphite binding powder of the present invention is used as a slide material, it is exposed to the outside of the final product and copper, which is the main material, And performs a function of preventing wear. The average particle size of the graphite powder particles can be preferably in the range of 5 to 200 micrometers. The graphite functions as a substance which interferes with and inhibits sintering of the product as an inorganic substance, and it is difficult to form and sinter the product because of its large size. In order to compensate for this, graphite powder to be used is advantageously small in particle size. Further, as described above, the average particle size of the graphite powder particles should be determined according to the relationship with the average particle size of the copper powder particles. Also, in the production of the copper-graphite bonded powder, most of the objects to be mixed are taken up by the copper powder as the main material. When the particle size of the graphite powder is large, the number of the particles of the graphite powder becomes small, It is considered that there is a possibility that the particles of the powder are localized in a specific region of the copper powder, which may cause a problem in the quality of the product.

The granular phase of the graphite powder particles is generally flattened and is externally exposed in a manner to be partially recessed-bonded to the copper matrix produced in the sintering process to perform a predetermined function. The binding force between the graphite powder particles and the copper matrix The surface of the product may be roughened by dropping out of the slide, and the frictional resistance and the like may be lowered. Therefore, such a problem can be solved by coating the surface of the graphite powder particles with the same components as those of the matrix of copper or the like.

The lubricant powder further comprises a function (first function) of being positioned between a plurality of copper-graphite binding particles to improve flowability (lubrication) during injection of the metal mold. Further, (Graphite powder particles) and graphite powder particles are relatively floating (segregation) with respect to the copper powder particles, although the density of the copper powder particles and the graphite powder particles are different from each other, , The effect of preventing the aggregation of the respective powder particles is prevented.

The lubrication function, which is the first function, is a function of lubrication which acts between the wall of the die where the powder is compressed and the copper-graphite powder to prevent excessive friction between the green compact and the die, And the lubricating action that ensures the flowability in the process of being loaded into the die. Particularly in the former case, it is possible to reduce the force (extraction force) for separating the green compact from the die to maintain the life of the die, and to prevent damage to the die surface and the product surface in advance.

The lubricant powder of the present invention maintains a solid state in a state where copper powder particles and graphite powder particles are bonded (at a second function) at room temperature, and does not have a liquid phase at room temperature. Any kind of lubricant may be used without limitation to a specific material as long as it is used as a lubricant for powders. In the present invention, as such a lubricant powder, lithium stearate (Li-C18H36O2), zinc stearate (Zn-C18H36O2), Acrawax (C38H76N2O2), kenolube paraffin, aluminum stearate Stearate, paraffin wax, and the like. It is, of course, not limited to these materials as described above. Lithium stearate, zinc stearate and the like are metal soaps which are metal salts other than alkali metals as salts of higher fatty acids, and generally have insolubility. These lubricants basically function to improve the flowability while being present between the metal powder particles. Furthermore, these lubricants have the advantage of burning at a preheating stage (500 to 600 degrees Celsius) of the sintering process, leaving less impact on the product. Further, these lubricants have a rust inhibiting function for preventing the deterioration of copper powder as a main material through the function of removing moisture on the metal powders.

It is proposed that the lubricant powder of the present invention is added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the total of the copper-graphite bond powder. The lubricant powder of the present invention is a powder of a lubricant which is formed by a predetermined process to be described later, in which a part of the initial blend (powder form) is melt-denatured in a liquid phase to serve as a binder and the remainder remain in powder form, Since the lubrication function is performed, the initial mixing amount has an important meaning. Accordingly, when the lubricant powder is contained in an amount of less than 0.1 part by weight based on the total weight of the lubricant, there arises a problem that the above-mentioned binder agent and lubricant can not be simultaneously performed. If the amount of the lubricant powder is more than 3.0 parts by weight based on the total weight portion, there is a problem that the ratio of the void space generated in the product while the lubricant powder particles are burned in the sintering process (or the preheating step) There is a problem that a metal residue which may contaminate the inside of the sintering furnace can be left over by an allowable value.

Second, the copper powder, the graphite powder, and the lubricant powder are simultaneously introduced into a mixer. At this time, it is possible to further input the alloy powder. As the alloy powder, tin, lead, bismuth, a lead-tin alloy for producing the process-type alloy and an alloy thereof can be selected. Other known alloy powders for improving the physical properties of the alloy are not excluded.

The mixer in the second stage may be any type of machine as long as the machine can move the particle by mechanical action to move the position or make the uniformization by slipping or impulse. The mixer may be a double cone mixer, But are not limited to, a pan drum mixer, a horizantal cylinder mixer, an inclined cylinder mixer, and the like.

Third, primary mixing is performed for a predetermined time. The primary mixing has the meaning of preliminarily mixing the respective mixing components prior to mixing by the zero-gravity mixer described later.

Fourth, in the third step, the primary mixed mixture is put into a weightless mixer.

The zero gravity mixer is designed so that a plurality of paddles are overlapped on two rotating shafts (Twin Shaft) in a mixing chamber so that the material is transported by the constant speed rotation, A mixing zone is formed and a non-gravity fluidized bed is formed in the mixed region regardless of the particle size, the viscosity, and the shape of the raw material to perform mixing. The two paddle shafts in the mixing room rotate in opposite directions and the paddles mounted on each axis form a fluidized bed region by dispersing the mixed materials in different directions according to the constant tip speed. Since the rotating shaft is low speed, the shock and shear force So that the mixing is proceeded without damaging the raw material. The raw material transfer is concentrated from the bottom of the mixer to the central upper layer portion, so that the effective volume of the mixing chamber increases and the collision and friction between the raw materials decrease as the effective volume increases. Accordingly, the shape of the particles is preserved and pressure is applied to the rotating body and the discharge port, thereby preventing leakage of the material in the seal portion and progressing the mixing.

However, since the use of the zero gravity mixer proposed in the present invention is for performing the efficient mixing operation as described above, the mixer capable of performing such an operation is not necessarily limited to the zero gravity mixer.

Fifth, low-speed mixing is performed for a predetermined time while maintaining the first temperature in the zero-gravity mixer. At this stage, a part of the lubricant powder is melted to bind (bind) the particles of the copper powder and the particles of the graphite powder. When the lubricant powder is mixed with the metal composite powder in the form of a powder in the usual manner, the lubricant powder, the copper powder and the graphite powder can be independently moved relative to each other, so that the problem of the above-described deterioration can be maintained. Therefore, in the present invention, a part of the lubricant powder is melted and used to serve as a binder agent for bonding the copper powder and the graphite powder through the heating-mixing process, thereby eliminating the segregation phenomenon. In short, the lubricant powder of the present invention is such that a part of the initial blend (powder form) is denatured (melted) in the liquid phase by this step to serve as a binder between the particles of the copper powder and the particles of the graphite powder, Min remains in powder form to perform internal lubrication between the copper-carbon bond particles and external lubrication with the die during the subsequent compaction process. The first temperature may be set to be not less than 100 degrees Celsius and not more than 190 degrees Celsius, and more preferably not less than 100 degrees Celsius and not more than 180 degrees Celsius. If the temperature is lower than 100 ° C, the lubricant powder is not partially melted and binding between particles of the graphite powder and the copper powder does not occur. If the temperature is higher than 180 ° C, particles are overheated and copper- There arises a problem that the particle size of the binding particles is increased and the product density is lowered.

The mixing time in this step should be determined considering that a part of the lubricant powder is melted and flows between the particles of the copper powder and the particles of the graphite powder to bond them to each other because considerable time is required due to the viscosity of the melt do. Specifically, it should be determined according to the process temperature, the amount of the mixed raw materials, the composition ratio, and the like.

In the fifth step, an inert gas may be introduced to prevent oxidation at a high temperature during bonding. Examples of the inert gas include, but are not limited to, nitrogen and argon.

Furthermore, when the powders for alloying are mixed together, the particles of the alloy powder can also be bonded to the particles of the copper powder by the partially melted portions of the lubricant powder. (The actual alloying process, of course, proceeds in the sintering process.) This makes it possible to prevent segregation of the powder for alloying in the mixed (combined) powder. Further, a plurality of alloying powders may be combined with one copper powder (this is determined by the particle size).

In addition, the method may further include a step of low-speed mixing for a predetermined time while raising the temperature from room temperature to the first temperature in the zero-gravity mixer before the fifth step. The temperature profile at this time may be linearly increased in temperature over time, or may be varied in various ways, such as a pattern for increasing the temperature by a quadratic function. Should be examined and conducted experimentally.

Sixth, the second temperature lower than the first temperature is maintained in the zero-gravity mixer, and low-speed mixing is performed for a predetermined time. As a result, a part of the lubricant powder which has been melted in the previous step and is allowed to couple the particles of the copper powder and the particles of the graphite powder is solidified again (cooling and solidifying because the second temperature is lower than the melting point of the lubricant powder) And continues to bond the particles of the copper powder and the particles of the graphite powder. The reason for cooling to the second temperature is to prevent the powder from being oxidized when the powder is discharged at a high temperature, and the reason why the powder is rotated at a low speed is because the powder is too advanced and powder characteristics may be different from the initial powder . In addition, since the lubricant powder has a solid phase at room temperature, it does not cause a problem of deterioration of flowability unlike liquid phase additives. The mixing time of this step should be determined according to the process temperature, the amount of the mixed raw materials, the composition ratio, and the like.

Seventh, the powder is discharged from the zero-gravity mixer and completed.

Thereafter, the effluent may be separated to a predetermined size and further mixed in a mixer. This is to mix the coarse powder and the fine powder evenly by adjusting the final particle size distribution depending on the position - the particles located on the bottom and the particles located above the mixer may have different average particle sizes. At this time, the mixer can use various mixers such as a double cone mixer.

With respect to the composition ratio of the copper-graphite binding powder, in the present invention, 0.5 to 10.0 parts by weight of the graphite powder, 0.1 to 3.0 parts by weight of the lubricant powder, 5.0 to 13.0 parts by weight of the tin powder, Parts by weight and the balance of the copper powder. When the graphite powder is contained in an amount of less than 0.5 parts by weight, the effect of improving the strength and lubricating action of the sintered product is insufficient, while if it exceeds 10 parts by weight, the strength of the sintered product is lowered. When the content of the tin powder is less than 5.0 parts by weight, there is a problem in strength, corrosion resistance, and abrasion resistance. When the tin powder is contained in an amount exceeding 13.0 parts by weight, there arises a problem of increased brittleness do.

In addition, the green compact can be manufactured using the copper-graphite binding powder produced by the manufacturing method of the present invention. As an example of the green compact, a toroidal or other type of pressure-sensitive core or the like may be used. These green compacts may be further formed through a sintering process after the greening process. Generally, lubricants should be taken into consideration when there is a problem in reducing the discharge pressure when the height of the manufactured product is large. In addition, the influence of reduction of the die friction of the lubricant should be grasped to determine the pressure acting on the die and the output power.

Such a green compact is also an intermediate material for producing a product such as a bearing or a bush in which a dynamic load is repeatedly applied. After the sintering process, the graphite particles contained in the copper- Thereby performing a friction reduction function.

EXAMPLES Hereinafter, examples of the present invention will be described together with comparative examples.

[Example 1]

≪ Preparation of copper powder &

100% purity of copper was atomized using hydration and the sprayed powder was dried at a temperature of about 120 degrees Celsius.

Under a nitrogen / Ax air atmosphere, at a temperature range of about 600 to 700 degrees Celsius, and the reduced powder passed through was crushed using a hammer mill.

Thereafter, 100 meshes were classified.

≪ Preparation of mixed powder &

Copper powder, tin powder, graphite powder, and zinc stearate powder were simultaneously charged into a double cone mixer at a rate of 88.3 wt%, 10 wt%, 1 wt%, and 0.5 wt%, respectively.

The primary blended mixed powders were put into a weightless mixer, and low speed mixing was performed while slowly raising the temperature from room temperature to 170 degrees Celsius for 30 minutes.

Thereafter, low-speed mixing was performed while maintaining the temperature at 170 DEG C for 50 minutes.

Thereafter, the mixture was cooled with low speed mixing from 170 to 65 degrees Celsius for 2 hours, and then the powder was discharged.

The discharged powders were classified into 80 mesh and 60 mesh, and then mixed in a double cone mixer for 3 minutes.

[Example 2]

Graphite powder was mixed in an amount of 3 wt%.

[Example 3]

Graphite powder was mixed in an amount of 5 wt%.

[Example 4]

Except that graphite powder was mixed in an amount of 7 wt%.

[Comparative Example 1]

≪ Preparation of copper powder &

Was prepared under the same conditions as in Example 1.

≪ Preparation of mixed powder &

Copper powder, tin powder, graphite powder, and zinc stearate as a lubricant were prepared at a mixing ratio of 88.3 wt%, 10 wt%, 1 wt%, and 0.5 wt%, respectively.

Copper powder, tin powder, zinc stearate powder and graphite powder were sequentially added to a double cone mixer to perform mixing.

[Comparative Example 2]

Except that graphite powder was mixed in an amount of 3 wt%.

[Comparative Example 3]

Except that graphite powder was mixed in an amount of 5 wt%.

[Comparative Example 4]

Except that graphite powder was mixed in an amount of 7 wt%.

The results of measurement of density (A.D.), fluidity (F.R.) and particle size characteristics of the mixed powders prepared in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 below.

division unit Comparative Example 1 Experimental Example 1 Comparative Example 2 Experimental Example 2 Comparative Example 3 Experimental Example 3 Comparative Example 4 Experimental Example 4 A.D. g / cm3 2.93 3.16 2.68 2.92 2.33 2.63 2.10 2.44 F.R Sec / 50g 43.9 28.2 53.8 39.5 - 53.4 - 66.1 +106
μm

Wt% 1.5 2.5 1.7 2.4 1.6 1.8 1.5 1.7 +75 12.4 13.2 12.2 11.8 11.0 11.5 10.7 11.2 +45 37.4 38.6 37.6 38.1 36.1 36.3 35.1 35.8 -45 48.7 45.7 48.5 47.7 51.3 50.4 52.7 51.3

From the viewpoint of the apparent density (AD Apparent Density), the values in the experimental examples were measured to be larger than those in the corresponding comparative examples. As a result, in the case of the particle size, the proportion of the differential in the experimental example was somewhat reduced, It is analyzed that the ratio is slightly increased. As the outer density increases, the strength and weight reduction rate become better. Therefore, it can be understood that the embodiments are more advantageous in comparison with the comparative examples. In the case of the flow rate (F.rate), it can be confirmed that the case of the embodiment is improved to a considerable extent as compared with the case of the comparative example. Particularly, in the case of mixed powders containing graphite in an amount of 5% or more, it was determined that there was no flowability in Comparative Examples 3 and 4, but flowability was measured in Examples 3 and 4. This property facilitates die filling for subsequent compaction and sintering, resulting in improved quality, such as reduced product weight / dimensional variation. This improvement in flowability is due not only to the fact that the lubricant powder is included but also to the structural properties in which the graphite powder and the copper powder are combined by the molten part (binder) of the lubricant powder.

Hereinafter, experimental examples for confirming the improvement of characteristics of a product made of the copper-graphite binding powder of the present invention will be described.

[Experimental Example 1]

<Manufacture of press>

The mixed powder according to Examples 1 to 4 and Comparative Examples 1 to 4 was charged into a die for forming a toroidal green compact having an outer diameter of 12.03 mm, a width of 3 mm and a height of 4 mm, A pressurizer of 6.2 g / cc was manufactured. In the course of 200 continuous molding steps at a rate of 14 per minute, 50 randomly selected weight standard deviations were measured for the single-piece standard (2.12 g 0.02 g).

The results are shown in Table 2 below.

Comparative Example 1 Experimental Example 1 Comparative Example 2 Experimental Example 2 Comparative Example 3 Experimental Example 3 Comparative Example 4 Experimental Example 4
Standard Deviation
0.0062
0.0034
0.0092
0.0053
0.0131
0.0071
0.0145
0.0075

As mentioned above, it has been observed that when the flowability of the mixed powder is improved, the deviation in the center of gravity of the green compact is also reduced and the quality is improved.

 [Experimental Example 2]

<Manufacture of press>

The mixed powder according to Examples 1 to 4 and Comparative Examples 1 to 4 was charged into a die for molding a toroidal green compact having an outer diameter of 22.5 mm, a width of 4.25 mm and a height of 5 mm, Was selected as an arbitrary number of 50 pieces in the process of forming 200 pieces continuously at a rate of 14 pieces per minute.

<Manufacture of sintered body>

Thereafter, the 50 green compacts selected previously were subjected to a preheating zone (450 to 550 degrees, 30 to 60 minutes), a normal temperature (700 to 800 degrees Celsius, 30 to 60 degrees Celsius) 60 minutes) and a sintering furnace having a temperature profile of a cooling zone (about 500 DEG C, 60 to 120 min) for 30 minutes (760 DEG C) to form a sintered body and measuring the outer diameter After that, the outer diameter shrinkage ratio was calculated in comparison with that of the green compact.

The results are shown in Table 3 below.

Comparative Example 1 Experimental Example 1 Comparative Example 2 Experimental Example 2 Comparative Example 3 Experimental Example 3 Comparative Example 4 Experimental Example 4
Standard Deviation

0.0464
0.0283
0.0443
0.0291
0.0505
0.0314
0.0594
0.0351

As mentioned above, it has been observed that when the flowability of the mixed powder is improved, the dimensional deviation of the product after sintering is also reduced, and the quality is improved.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (11)

A method for producing a copper-graphite bonded powder for use in the production of a slide member comprising a bearing and a bush,
(i) preparing a copper powder, a graphite powder and a lubricant powder;
(ii) simultaneously injecting the copper powder, the graphite powder and the lubricant powder into a mixer;
(iii) performing a primary mixing with the copper powder, the graphite powder and the lubricant powder introduced in the step (ii);
(iv) introducing the primary blended mixture into the weightless mixer in the step (iii);
(v) mixing and maintaining a first temperature within the zero-gravity mixer such that a portion of the lubricant powder melts to form particles of the copper powder and particles of the graphite powder;
(vi) mixing in the non-gravity mixer while being lowered to a second temperature lower than the first temperature to melt the copper powder particles and the graphite powder particles melted in the step (v) A step of solidifying again;
(vii) discharging powder from the zero-gravity mixer,
The lubricant powder is a mixture of the copper powder and the graphite powder, and the lubricant powder serves as a binder by replacing a part of the original powder mixture in the form of a liquid to form a liquid, and the remainder of the original mixture remains in powder state, The inner lubrication function between the bonded powder particles and the outer lubrication function between the die during the subsequent compaction process,
The lubricant powder is added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the total of the copper-graphite bond powder,
In the step (ii), the alloy powder is further introduced,
Wherein the particles of the alloy powder are bonded to the particles of the copper powder by the lubricant powder to prevent segregation.
The method according to claim 1,
Wherein the alloy powder is tin, lead, bismuth, or an alloy thereof.
delete The method according to claim 1,
The lubricant powder in the step (i) is selected from the group consisting of lithium stearate, zinc stearate, Acrawax (C38H76N2O2), kenolube paraffin, aluminum stearate, paraffin wax Wherein the copper-graphite alloy powder is at least one selected from the group consisting of copper and graphite.
The method according to claim 1,
Wherein the first temperature in the step (v) is in the range of 100 ° C to 180 ° C.
The method of claim 5,
Further comprising a step of raising and lowering the temperature within the non-gravity mixer from room temperature to the first temperature between the step (iv) and the step (v).
The method according to claim 1,
Wherein the second temperature in the step (vi) is 40 to 90 degrees Celsius.
The method of claim 2,
(Ii), 0.5 to 10.0 parts by weight of the graphite powder, 0.1 to 3.0 parts by weight of the lubricant powder, 5.0 to 13.0 parts by weight of the tin powder, and the remaining amount of the copper powder are added to 100 parts by weight of the total 100 parts by weight of the copper- Wherein the copper-graphite alloy powder is introduced into the copper-graphite alloy powder.
The method according to claim 1,
Further comprising, after the step (vii), further separating the effluent of (vii) and further mixing in a mixer.
A copper-graphite bond powder produced by the method for producing a copper-graphite bond powder of claim 1.
A green compact produced by using the copper-graphite binding powder of claim 10.

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