CN108453262B

CN108453262B - Graphene powder metallurgy oil-retaining bearing and preparation method thereof

Info

Publication number: CN108453262B
Application number: CN201810246741.6A
Authority: CN
Inventors: 沙嫣; 沙晓林
Original assignee: Nantong Qiangsheng Graphene Technology Co ltd
Current assignee: Nantong Qiangsheng Graphene Technology Co ltd
Priority date: 2018-03-23
Filing date: 2018-03-23
Publication date: 2021-08-13
Anticipated expiration: 2038-03-23
Also published as: CN108453262A

Abstract

The invention provides a graphene powder metallurgy oil-retaining bearing and a preparation method thereof, wherein the oil-retaining bearing comprises the following components in percentage by mass: sn element powder: 6.0 to 8.0 percent; enhancer: 1.0-5.0%; lubricant: 2.0 to 6.0 percent; graphene: 0.005-0.5%; base metal powder: and (4) the balance. According to the invention, the wear resistance of the bearing assembly is improved by adding the graphene powder with large sheet diameter into the bearing piece, and meanwhile, the graphene modified lubricating oil is used in the oil immersion step, so that the oxidation stability of the lubricating oil can be greatly improved by the graphene with small sheet diameter, and the viscosity change coefficient of the lubricating oil is small in a high-temperature and low-temperature state, so that the prepared oil-containing bearing has excellent noise reduction performance, the oil film has stronger anti-shearing performance, the friction coefficient is smaller, and the service life of the bearing is longer.

Description

Graphene powder metallurgy oil-retaining bearing and preparation method thereof

Technical Field

The invention belongs to the technical field of powder metallurgy, and particularly relates to a graphene powder metallurgy oil-containing bearing and a preparation method thereof.

Background

The oil-retaining bearing of end metallurgy has good wear resistance and relatively low manufacturing cost, and is widely applied in industrial production, along with the development of powder metallurgy industry, the application field of the oil-retaining bearing of powder metallurgy is continuously widened, and the oil-retaining bearing of end metallurgy is particularly applied to fields of micro and special motors, office equipment, household appliances (air conditioners, refrigerators and the like) and the like of automobiles and is required to have ultra-low noise and ultra-long service life.

However, the friction reducing performance of the existing ultra-low noise and long-life powder metallurgy oil-retaining bearing is improved and the service life of the existing ultra-low noise and long-life powder metallurgy oil-retaining bearing is prolonged, the traditional method is to add lead to improve the friction reducing performance, and an oil core is surrounded on the outer surface of the oil-retaining bearing, but because the society pays attention to environmental protection, the application range of the powder metallurgy oil-retaining bearing manufactured by the method of adding lead is gradually reduced, and the amount of lubricating oil in the oil core surrounded by the outer surface of the oil core flowing to the boundary of an inner hole is little, so that the manufacturing, production and application of a new material with ultra-low noise and long service life are bound to be generated.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a graphene powder metallurgy oil-containing bearing and a preparation method thereof. According to the invention, the graphene element is added in the preparation of the oil-retaining bearing, so that the prepared graphene oil-retaining bearing has better anti-friction and noise-reducing effects, and the service life of the oil-retaining bearing is further prolonged. The oil-retaining bearing manufactured by the invention can be applied to the fields of micro and special motors, office equipment, household appliances (air conditioners, refrigerators and the like) and the like on automobiles, and the bearing is required to have ultralow noise and long service life.

The purpose of the invention is realized by the following technical scheme:

the invention provides a graphene powder metallurgy oil-retaining bearing which comprises the following components in percentage by mass:

preferably, the strengthening agent is a mixture of powder containing P element and powder containing Cr element; the P element-containing powder: 0.1-2.0%, powder of Cr element: 1.9-6.0%.

Preferably, the powder containing the P element is metal powder containing a phosphorus element in a powder element structure, such as ferrophosphorus powder, copper-phosphorus powder and the like; the Cr-containing element powder is pure metal chromium powder or alloy powder containing Cr.

Preferably, the lubricant is MoS₂And (3) powder.

Preferably, the base metal powder is at least one selected from copper powder and iron powder.

Preferably, the graphene comprises graphene oxide or graphene; the graphene oxide is selected from one or more of coupling agent modified graphene oxide, cationic surfactant modified graphene oxide, amino compound modified graphene oxide, bromoalkane modified graphene, amino compound modified graphene, polyvinylpyrrolidone modified graphene and polyvinyl alcohol modified graphene.

The invention also provides a preparation method of the graphene powder metallurgy oil-retaining bearing, which comprises the following steps:

A. preparing a graphene-base metal powder mixture: carrying out ball milling dispersion on the matrix metal powder and the graphene powder under the action of a dispersing agent to obtain a graphene-matrix metal powder mixture;

B. powder mixing: uniformly mixing Sn element powder, a reinforcer, a lubricant and a graphene-matrix metal powder mixture to obtain mixed powder;

C. low-temperature diffusion: carrying out low-temperature diffusion on the mixed powder under the protection of gas;

D. and (3) pressing and forming: c, performing compression molding treatment on the mixed powder treated in the step C to form a pressed blank;

E. sintering treatment: sintering the pressed compact in a reducing atmosphere to form an alloy sintered body;

F. oil immersion treatment: and (3) finishing, surface beating and ultrasonic cleaning the alloy sintered body, and then carrying out oil immersion treatment.

Preferably, in step a, the dispersant is selected from one or more of sodium dodecyl benzene sulfonate, cetyl trimethyl ammonium bromide, cetyl pyridine bromide, tween-80, span 40/60, sodium carboxymethyl cellulose, naphthalene sulfonate and polyacrylamide; the graphene powder is powder with the graphene sheet diameter of 320-1000 meshes.

Preferably, in the step C, the temperature of the low-temperature diffusion treatment is 200-400 ℃, and the time is 20-40 min.

Preferably, in the step D, the pressure of the compression molding treatment is 150-350MPa, and the compression density is controlled to be 5.5-6.5g/cm³。

Preferably, in step E, the sintering treatment specifically comprises: the temperature is raised to 500 ℃ after 0.5 to 1.5 hours, then the mixture is heated to 820 ℃ after 720 ℃ for main sintering for 0.5 to 1.5 hours, and then the mixture is cooled to the normal temperature after 0.5 to 1.5 hours.

Preferably, in step F, the lubricating oil used in the oil immersion treatment is graphene modified lubricating oil; the sheet diameter of the graphene is 2000 meshes.

Preferably, the preparation method of the graphene modified lubricating oil comprises the following steps: adding graphene into the lubricating oil.

According to the invention, the graphene element is added in the processing and preparation process of the original oil-retaining bearing, and due to the ultra-strong hardness of the graphene, the friction coefficient is close to an ultra-wet state, so that the friction resistance is greatly reduced, the anti-wear and anti-wear performance of the machine can be obviously improved by adding the graphene into the oil-retaining bearing, the abrasion between moving machines is reduced, and the service life of the graphene oil-retaining bearing is obviously prolonged.

The key technology of the invention is to blend the graphene into the oil-retaining bearing, and the treated graphene is added in a proper processing working section, so that the graphene can be organically combined with other metal powder in the oil-retaining bearing, the service life of the oil-retaining bearing is prolonged, and the performance of the oil-retaining bearing is improved.

The addition method of the graphene comprises two methods: (1) when the blank is manufactured by the oil-retaining bearing, graphene powder (with the particle size of 320-10000 meshes) and metal powder are mixed and pressed into a blank; (2) after the oil-retaining bearing is sintered, finished and ultrasonically cleaned, oil immersion treatment is required, and graphene modified lubricating oil with small particle size (between 2000 and 3000 meshes) is used, so that when the oil-retaining bearing is immersed, graphene powder with small particle size can enter a hollow channel of a bearing body along with the lubricating oil. When the two methods are used simultaneously, the radial crushing strength and the wear resistance of the bearing can be obviously improved, wherein the graphene powder with the size of 320-1000 meshes added in the first method mainly has the effect of improving the radial crushing strength of the oil-containing bearing; the 2000-3000-mesh graphene powder added in the second method mainly has the main effects that when the oil-retaining bearing runs, lubricating oil and graphene in a bearing channel can be separated out, and the ultra-lubrication effect of the graphene is utilized to reduce the friction between bearing components and improve the wear-resisting effect of the bearing components. Therefore, the two methods can achieve the best effect when used simultaneously.

Compared with the prior art, the invention has the following beneficial effects:

due to the ultra-strong hardness of the graphene, the friction coefficient of the graphene is close to an ultra-wet state, the friction resistance is greatly reduced, the wear resistance and the wear reduction performance of machinery can be obviously improved by adding the graphene into an oil-containing bearing, and the wear between moving machinery is reduced. Therefore, the graphene powder metallurgy oil-retaining bearing prepared by the method has the advantages of wear reduction, noise reduction, long service life and the like.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Examples 1 to 5

The embodiments 1 to 5 provide a graphene powder metallurgy oil-retaining bearing, the components and contents of which are shown in table 1, and the preparation method includes the following steps:

the method comprises the following steps: powder mixing (components and contents are shown in table 1): the preparation method comprises the following steps of uniformly mixing Sn element powder, a reinforcer, a lubricant and a graphene copper powder mixture (or iron powder and iron copper powder), wherein the key technology is the preparation of the graphene copper powder mixture, the preparation tool is a ball mill, the copper powder (or the iron powder and the iron copper powder) and the graphene powder (powder with the graphene sheet diameter of 320-1000 meshes) are subjected to ball milling dispersion through the ball mill under the action of a dispersing agent, so that the graphene is uniformly dispersed in base powder (containing the copper powder, the iron powder and the iron copper powder), and the used dispersing agent is one or a mixture of a plurality of sodium dodecyl benzene sulfonate, hexadecyl trimethyl ammonium bromide, hexadecyl pyridine bromide, tween-80, span 40/60, sodium carboxymethyl cellulose, naphthalene sulfonate and polyacrylamide. The graphene comprises graphene oxide or graphene; the graphene oxide is selected from one or more of coupling agent modified graphene oxide, cationic surfactant modified graphene oxide, amino compound modified graphene oxide, bromoalkane modified graphene, amino compound modified graphene, polyvinylpyrrolidone modified graphene and polyvinyl alcohol modified graphene.

Step two: low-temperature diffusion: and (3) performing low-temperature diffusion on the uniformly mixed powder in a diffusion furnace under the protection of nitrogen, wherein the low-temperature diffusion temperature is controlled at 200 ℃ and the time is 40 min.

Step three: and (3) pressing and forming: placing the powder after low-temperature diffusion into a die for compression molding, pressing into a pressed compact, wherein the pressing pressure is controlled to be 150MPa, and the pressing density is controlled to be 6.5g/cm³The equipment used for pressing and forming is one of a vertical oil press, a cold isostatic press, a hot isostatic press and a cam press.

Step four: sintering treatment: and gradually sintering and heating the pressed compact in the third step in a reducing atmosphere of nitrogen and hydrogen for 0.5-1.5 hours, heating to 500 ℃, then mainly sintering and heating to 720 ℃, keeping the temperature for 1.5 hours, then gradually cooling to normal temperature for 0.5-1.5 hours, and sintering to obtain the alloy sintered body.

Step five: finishing and surface finishing: and C, performing primary treatment on the sintered piece prepared in the fourth step, finishing the alloy sintered body, removing burrs on the sintered body, and performing compression shaping by using a compression die to obtain a pressed piece with a specified shape, a specified density and a specified dimensional precision.

Step six: ultrasonic cleaning and oil immersion treatment: and (3) ultrasonically cleaning the pressing part repaired in the fifth step for 30-45 minutes, and soaking the pressing part after the pressing part is cleaned, wherein the lubricating oil used in the fifth step is graphene modified lubricating oil, and the oxidation stability of the lubricating oil can be improved by adding graphene into the lubricating oil and utilizing the inert property of the graphene which does not react with strong acid and strong base, so that the viscosity change coefficient is small at high and low temperatures, and the noise reduction performance is better. The particle size of graphene powder used by the graphene modified lubricating oil is controlled to be about 2000 meshes, so that the graphene can conveniently enter a gap of a bearing piece along with the lubricating oil. The graphene comprises graphene oxide or graphene; the graphene oxide is selected from one or more of coupling agent modified graphene oxide, cationic surfactant modified graphene oxide, amino compound modified graphene oxide, bromoalkane modified graphene, amino compound modified graphene, polyvinylpyrrolidone modified graphene and polyvinyl alcohol modified graphene.

TABLE 1 Components and their percentages by mass of examples 1 to 5

	Sn powder	Fortifier	Lubricant agent	Graphene	Base metal powder
						Example 1	6％	2％	6％	0.005％	Balance of
Example 2	7％	5％	2％	0.1％	Balance of
						Example 3	8％	1％	3％	0.5％	Balance of
Example 4	7％	1％	4％	0.3％	Balance of
						Example 5	7％	1％	4％	0.3％	Balance of

Example 6

This example 6 provides a graphene powder metallurgy oil-retaining bearing, which has the same components and content as those in example 1, and the preparation method is substantially the same as that in example 1, except that: in this embodiment, the lubricating oil used in the sixth step is a conventional lubricating oil, and graphene is not added for modification.

Comparative example 1

This comparative example provides a powder metallurgy oil-retaining bearing having substantially the same components and amounts as in example 1, except that: no graphene was added in this comparative example. The preparation method comprises the following steps:

the method comprises the following steps: powder mixing: and uniformly mixing Sn element powder, a reinforcer, a lubricant and copper powder (or iron powder and iron copper powder).

Step six: ultrasonic cleaning and oil immersion treatment: and D, ultrasonically cleaning the pressing piece repaired in the fifth step for 30-45 minutes, and soaking the pressing piece after the pressing piece is cleaned, wherein the lubricating oil used in the fifth step is the lubricating oil used conventionally.

Comparative example 2

The comparative example provides a graphene powder metallurgy oil-retaining bearing, and the components and the content of the graphene powder metallurgy oil-retaining bearing are the same as those of example 1. The preparation method is basically the same as that of example 1, except that: in this embodiment, graphene is not added in the first step.

Comparative example 3

The comparative example provides a graphene powder metallurgy oil-retaining bearing, and the components and the content of the graphene powder metallurgy oil-retaining bearing are the same as those of example 1. The preparation method is the same as example 1, except that: in this comparative example, the sheet diameter of the graphene powder added in step one was about 2000 mesh.

Comparative example 4

The comparative example provides a graphene powder metallurgy oil-retaining bearing, the components and the content of which are the same as those of example 1, and the preparation method is basically the same as that of example 1, except that: in the comparative example, the first step is to mix Sn element powder, a reinforcer, a lubricant, graphene, copper powder (or iron powder and iron copper powder) and a dispersing agent uniformly.

Comparative example 5

The present comparative example provides a graphene powder metallurgy oil-retaining bearing, which has substantially the same components and contents as those of example 3, except that: in this comparative example, the graphene content was 0.8%. The preparation method is the same as in example 3.

Effect verification:

the powder metallurgy oil-retaining bearings prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in table 2.

TABLE 2

As can be seen from the results in table 2, by adding graphene in the bearing preparation process, since graphene is the strongest and hardest material at present, the radial crushing strength and apparent hardness of the bearing piece gradually increase with the increase of the addition amount of graphene, as in examples 1 to 6; when the addition amount of the graphene is too large, the graphene is easy to agglomerate at the moment, impurities are formed to destroy a metal continuous phase, and therefore the radial crushing strength and the apparent hardness are reduced, as in comparative example 5. Meanwhile, the oil content of the oil-containing bearing can be improved by proper addition amount of the graphene, and when the graphene content is continuously increased, the pressing density of the bearing blank is increased due to the fact that the particle size of the graphene is between 320 and 1000 meshes, so that the pores in the oil-containing bearing piece are reduced, the oil content is reduced, and the wear resistance of the oil-containing bearing piece is reduced. When the small-particle-size graphene is used in comparative example 3, the radial crushing strength is not adversely affected, but the oil content is reduced because the small-particle-size graphene reduces the pores of the bearing blank, and further, more lubricating oil cannot be stored during oil immersion, so that the oil content is reduced.

The invention has many applications, and the above description is only a preferred embodiment of the invention. It should be noted that the above examples are only for illustrating the present invention, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications can be made without departing from the principles of the invention and these modifications are to be considered within the scope of the invention.

Claims

1. The preparation method of the graphene powder metallurgy oil-retaining bearing is characterized by comprising the following steps:

F. oil immersion treatment: after finishing, surface beating and ultrasonic cleaning are carried out on the alloy sintered body, oil immersion treatment is carried out;

in the step F, the lubricating oil adopted in the oil immersion treatment is graphene modified lubricating oil; in the graphene modified lubricating oil, the sheet diameter of the adopted graphene is 2000 meshes;

the graphene powder metallurgy oil-retaining bearing comprises the following components in percentage by mass:

the graphene powder is powder with the graphene sheet diameter of 320-1000 meshes.

2. The method for manufacturing a graphene powder metallurgy oil-retaining bearing according to claim 1, wherein the reinforcing agent is a mixture of a powder containing a P element and a powder containing a Cr element; the powder containing the P element comprises the following components in percentage by mass in an oil-retaining bearing: 0.1-1.0%, wherein the mass content of Cr element powder in the oil-retaining bearing is as follows: 0.9-4.0%.

3. The method for preparing a graphene powder metallurgy oil-retaining bearing according to claim 1, wherein the lubricant is MoS₂And (3) powder.

4. The method for preparing the graphene powder metallurgy oil-retaining bearing according to claim 1, wherein the graphene powder comprises graphene oxide or graphene; the graphene oxide is selected from one or more of coupling agent modified graphene oxide, cationic surfactant modified graphene oxide, amino compound modified graphene oxide, bromoalkane modified graphene, amino compound modified graphene, polyvinylpyrrolidone modified graphene and polyvinyl alcohol modified graphene.

5. The method for manufacturing a graphene powder metallurgy oil-retaining bearing according to claim 1, wherein the base metal powder is at least one selected from copper powder and iron powder.

6. The method for preparing the graphene powder metallurgy oil-containing bearing according to claim 1, wherein in the step a, the dispersant is selected from one or more of sodium dodecyl benzene sulfonate, cetyl trimethyl ammonium bromide, cetyl pyridine bromide, tween-80, span 40/60, sodium carboxymethyl cellulose, naphthalene sulfonate, and polyacrylamide; the graphene powder is powder with the graphene sheet diameter of 320-1000 meshes.

7. The method for preparing the graphene powder metallurgy oil-retaining bearing according to claim 1, wherein in the step C, the temperature of the low-temperature diffusion treatment is 200-400 ℃, and the time is 20-40 min.

8. The method for preparing the graphene powder metallurgy oil-retaining bearing according to claim 1, wherein in the step D, the pressure of the compression molding treatment is 150-350MPa, and the compression density is controlled to be 5.5-6.5g/cm³。

9. The method for preparing the graphene powder metallurgy oil-retaining bearing according to claim 1, wherein in the step E, the sintering treatment specifically comprises: the temperature is raised to 500 ℃ after 0.5 to 1.5 hours, then the mixture is heated to 820 ℃ after 720 ℃ for main sintering for 0.5 to 1.5 hours, and then the mixture is cooled to the normal temperature after 0.5 to 1.5 hours.