CN114940922B

CN114940922B - Method for improving pores of metal-based porous lubricating material

Info

Publication number: CN114940922B
Application number: CN202210680218.0A
Authority: CN
Inventors: 陈辉; 许崇海; 肖光春; 罗婷; 衣明东; 陈照强; 张静婕
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2023-03-24
Anticipated expiration: 2042-06-16
Also published as: CN114940922A

Abstract

The invention discloses a method for improving pores of a metal-based porous lubricating material, which is characterized in that the prepared metal-based porous lubricating material is immersed into beta-diketone or organic solution thereof which can slowly react with metal, so that the pores in the material are improved without reducing the strength of the material. Different from the traditional technology, the invention does not improve by adding a reinforcing phase, improving the appearance of raw materials, using a novel pore-forming agent and other traditional modes in the sintering or other preparation processes, but immerses the material in liquid which can slowly react with metal after the preparation of the material is finished; the improvement method of the invention can improve the porosity, the pore morphology and the connectivity of the material, and simultaneously does not damage the integral structure of the material and does not generate adverse effect on the strength of the material.

Description

Method for improving pores of metal-based porous lubricating material

Technical Field

The invention relates to the field of porous lubricating materials, in particular to a pore improvement method for a metal-based porous lubricating material.

Background

The oil content and the crushing strength are two important indexes for measuring the service performance of the porous lubricating material, but the oil content and the crushing strength are mutually restricted, and the high oil content means that the material has more internal pores, which undoubtedly has adverse effect on the strength of the material. At present, the strength of the porous lubricating material is improved on the basis of ensuring the porosity mainly by adding an alloy element or a metal oxide reinforcing phase, improving the appearance of raw materials, using a novel pore-forming agent and the like in the preparation process, and the defects of the measures are that the manufacturing cost is increased and the manufacturing process is more complicated.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for improving the pores of a metal-based porous lubricating material, which improves the pores in the material without reducing the strength of the material. Different from the traditional technology, the metal-based porous lubricating material is immersed into beta-diketone or an organic solution thereof, and after a period of slow chemical reaction, the porosity of the material can be improved, the pore morphology can be improved, the connectivity can be improved, and meanwhile, the overall structure of the material cannot be damaged, so that the strength of the material cannot be adversely affected.

The technical scheme of the invention is as follows:

an improved method for the pore space of the metal-base porous lubricating material includes immersing the prepared porous lubricating material in beta-diketone or its organic solution which can slowly react with metal.

The improvement method of the invention does not improve by adding a reinforcing phase, improving the appearance of the raw material, using a novel pore-forming agent and other traditional ways in the sintering or other preparation processes, but immerses the material in beta-diketone or organic solution thereof which can slowly react with metal after the preparation of the material is finished.

The product of the reaction of the organic solution with the metal can be dissolved or can have an effect of improving lubrication.

The metal chelate generated by the reaction of the beta-diketone organic liquid and the metal has the function of improving the lubricating property and can play the roles of an antioxidant and an anti-wear agent. Therefore, the cleaning link can be avoided after the metal-based porous lubricating material is treated by using the beta-diketone organic liquid.

Preferably, the organic solution in the beta-diketone organic solution is a small molecule alcohol with the carbon number of 4 or less.

The beta-diketone or the active ingredient in the organic solution thereof is a micromolecular organic matter, the micromolecule in the active ingredient can be filled into finer pores and can be subjected to chemical reaction with metal on the inner walls of the pores, the pore size is enlarged, the pore morphology and pore connectivity are improved, the aperture ratio is increased, oil can conveniently enter the matrix from the outside, and the oil storage capacity of the matrix is further improved.

Preferably, the mass fraction of the beta-diketone in the beta-diketone organic solution is 10-99%.

Preferably, water is added to the beta-diketone or organic solution thereof when the metal-based porous lubricating material and the beta-diketone or organic solution thereof are chemically reacted.

Preferably, water is added in an amount of 1/5 to 5 times as much as the beta-diketone.

By adding a proper amount of water to the liquid, the reaction speed of the liquid and the metal is adjusted; when the addition amount of the water is 1/5 to 5 times of the beta-diketone, the reaction rate is faster, the beta-diketone has tautomerism of enol and ketone, metal is more easily dissolved by the beta-diketone when the proportion of enol is higher, the proportion of enol and ketone in the beta-diketone solution can be changed by adding the water, and when the addition amount of the water is 1/5 to 5 times of the beta-diketone, the proportion of enol and ketone in the beta-diketone solution can enable the beta-diketone and the metal to be at a faster reaction rate.

Preferably, when the metal-based porous lubricating material and the beta-diketone or the organic solution thereof are subjected to chemical reaction, oxygen is introduced into the beta-diketone or the organic solution thereof, the flow rate of the introduced oxygen is 0.5-20L/min, the oxygen can accelerate the reaction rate, and in the reaction of the beta-diketone and the metal, the dissolved oxygen in the beta-diketone solution plays an important role, and the oxygen also directly participates in the reaction of the beta-diketone and the metal, so that the reaction rate can be accelerated by introducing certain oxygen.

Preferably, when the metal-based porous lubricating material and the beta-diketone or organic solution thereof are subjected to chemical reaction, the reaction temperature is changed, the reaction temperature is between room temperature and 100 ℃, the reaction of the beta-diketone and the metal can be carried out at room temperature, the reaction rate can be accelerated by properly increasing the temperature, but the beta-diketone or organic solution thereof is taken as organic liquid and has certain volatility, and the volatilization rate can be increased even the beta-diketone or organic solution thereof is boiled when the temperature is too high.

The specific temperature is determined according to the melting point, boiling point and reaction rate of the liquid with different metals.

Preferably, before the metal-based porous lubricating material and the beta-diketone or organic solution thereof are chemically reacted, the metal-based porous lubricating material is soaked in the beta-diketone or organic solution thereof for a period of time, and the soaking process is carried out in a vacuum drying oven.

In the soaking process, the small molecules in the effective components in the beta-diketone or the organic solution thereof can be filled in the tiny pores of the metal-based lubricating material, the soaking process is carried out in a vacuum drying oven, and the rate of filling the pores with the small molecules is accelerated under the vacuum condition.

Preferably, the reacted metal-based porous lubricating material is dried in a vacuum drying oven.

Preferably, the pore modification is performed on a porous material containing a certain amount of metal components.

The above-mentioned improvement method can improve the porosity of the metal-based porous lubricating material, and the porosity of the porous material containing a certain amount of metal components produced by other new techniques can also be improved by the above-mentioned improvement method.

A method for improving the porosity of a metal-based porous lubricating material comprises the following steps:

step 1: completely soaking the metal-based porous lubricating material to be treated in a container containing beta-diketone or an organic solution thereof, placing the container in a vacuum drying oven, adjusting the vacuum degree and the temperature, keeping for a period of time, recovering the pressure and the temperature in the vacuum drying oven to normal pressure and normal temperature, and taking out the container.

And 2, step: covering the container with a cover, partially or completely sealing the container, reducing the volatilization of the liquid, and reacting for a period of time; according to the components of the selected liquid and the metal-based porous lubricating material, a proper amount of water, a certain flow of oxygen or reaction temperature can be added into the liquid to achieve the purpose of regulating the reaction rate.

And step 3: fishing out the metal-based porous lubricating material from the liquid after the step 2 is completed.

And 4, step 4: the metal-based porous lubricating material is repeatedly washed by other organic solvents such as clean ethanol or acetone, and ultrasonic cleaning and other means can be adopted to ensure the cleaning effect, and the metal-based porous lubricating material is fully dried after being cleaned. The step is an optional step, if the reaction product of the metal-based porous lubricating material and the liquid does not have adverse effect or can play a beneficial role in later use, the operation is not needed, and the metal-based porous lubricating material is directly fished out and dried after the reaction is finished.

And 5: and (3) testing the properties such as oil content, strength and the like of the treated metal-based porous lubricating material, and repeating the steps 1-4 if the oil content is not increased to the expected value and the mechanical properties such as strength are not reduced or the reduction range is within the acceptable range.

The metal-based porous lubricating material has a meaning known in the art, can be divided into iron-based, copper-based, aluminum-based and other metal-based porous lubricating materials, is usually prepared by a powder metallurgy sintering technology and a 3D printing technology, and common metal-based porous lubricating materials comprise Fe-C series, fe-Cu-C series, fe-Pb-Cu series, al-Cu, al-Zn, al-Sn, al-Cu-Mg, cu-Sn and the like.

Preferably, according to the invention, the beta-diketones have the meaning known in the art, commonly used beta-diketones are acetylacetone (2, 4-pentanedione), trifluoroacetylacetone (1, 1-trifluoro-2, 4-pentanedione), hexafluoroacetylacetone (1, 5-hexafluoro-2, 4-pentanedione) trifluoro-1- (2-furyl) -1, 3-butanedione, 2-thenoyltrifluoroacetone (4, 4-trifluoro-1- (2-thienyl) -1, 3-butanedione), benzoyltrifluoroacetone (4, 4-trifluoro-1-phenyl-1, 3-butanedione), and the like.

The invention has the technical characteristics and beneficial effects that:

the invention improves the pores of the metal-based porous lubricating material by utilizing the slow chemical reaction between the liquid and the metal after the preparation of the metal-based porous lubricating material, and has simple operation and low cost.

The reaction rate of the metal and the liquid is slow, the reaction rate can be controlled by adding water into the liquid, controlling the temperature and the oxygen content, the reaction is controllable, only limited chemical reaction is carried out with the surface metal, and no obvious adverse effect is generated on the mechanical properties such as strength, hardness and the like of the material. Meanwhile, the characteristic of high specific surface area of the porous material is utilized, and the porosity of the material can be effectively improved.

The effective component of beta-diketone or its organic solution is small molecular organic matter, such as acetylacetone with molecular weight of 100.11, and because the low molecular hydrocarbon can increase volatility and reduce flash point, most commercial lubricants are large molecular organic matter with molecular weight above 300, even higher than thousands. The micromolecules in the effective components can be filled into finer pores and can be subjected to chemical reaction with metals on the inner walls of the pores, the pore size is enlarged, the pore appearance and pore connectivity are improved, the aperture ratio is increased, oil can conveniently enter the matrix from the outside, and the oil storage capacity of the matrix is further improved.

The metal chelate compound generated by the reaction of the preferable beta-diketone organic liquid such as acetylacetone and the like and the metal has the function of improving the lubricating property and can play the roles of an antioxidant and an anti-wear agent. Therefore, the cleaning link can be eliminated after the metal-based porous lubricating material is treated by using the liquid.

Drawings

FIG. 1 is a reaction equation of a metal with acetylacetone in the presence and absence of oxygen, in which M represents a metal.

FIG. 2 is a chemical structural formula of a chelate iron acetylacetonate formed by reacting metallic iron with acetylacetone.

Detailed Description

The invention is further illustrated by the following examples and figures:

the invention utilizes slow chemical reaction between liquid and inner wall of pore of metal-based porous lubricating material to improve porosity, fig. 1 is reaction equation of acetylacetone and metal (iron, aluminum, copper, magnesium, etc.) in aerobic (reaction formula 1) and anaerobic (reaction formula 2) conditions, and fig. 2 is chemical structural formula of metal chelate iron acetylacetonate generated by reaction of acetylacetone and iron.

Selecting a metal-based oil-containing bearing as a test sample, respectively testing the oil content and the crushing strength of the materials before and after treatment, selecting 5 samples for each material, and averaging the final results. The specific test method comprises the following steps: measuring the oil content of the material according to a method specified in GB/T5165-26 determination of oil content of permeable sintered metal material; the radial crushing strength of the oil-impregnated bearing was measured according to the method specified in the standard GB/T6804-2008 "determination of radial crushing strength of sintered metal bush".

Example 1

A method for improving the pores of a metal-based porous lubricating material comprises the following steps:

step 1: for a commercially available Fe-based oil-impregnated bearing, the oil content and the crushing strength were measured to be 13.7% and 453MPa, respectively.

And 2, step: and (2) completely soaking the Fe-based oil-retaining bearing in the step (1) in a beaker filled with 500ml of acetylacetone, then placing the beaker in a vacuum drying oven, vacuumizing to enable the pressure in the drying oven to be below 0.1MPa, setting the temperature of the drying oven to be 25 ℃, keeping for 30 minutes to enable the pressure and the temperature in the vacuum drying oven to be restored to the normal pressure and the normal temperature, and taking out the beaker.

And 3, step 3: the beaker of step 1 was covered with a lid to reduce the amount of volatile acetylacetone but without sealing, and reacted at room temperature for 72 hours.

And 4, step 4: and 3, fishing out the Fe-based oil-containing bearing from the beaker after the reaction in the step 3 is finished, and drying the Fe-based oil-containing bearing for 1 hour at the temperature of 45 ℃ in a vacuum drying oven.

And 5: the oil content and the crushing strength of the Fe-based oil-retaining bearing treated in the above steps were measured to be 15.2% and 446MPa, respectively.

Example 2

step 1: for a commercially available Cu-Sn-based oil-impregnated bearing, the oil content and the crushing strength were measured to be 18.3% and 263MPa, respectively.

Step 2: pouring 500ml of an ethanol solution with the trifluoroacetylacetone content of 40wt% into the beaker, and completely soaking the Cu-Sn-based oil-retaining bearing in the step 1 in the solution; placing the beaker in a vacuum drying oven, vacuumizing to make the pressure in the drying oven reach below 0.1MPa, setting the temperature of the drying oven at 40 ℃, keeping for 30 minutes to make the pressure and the temperature in the vacuum drying oven return to the normal pressure and the normal temperature, and taking out the beaker.

And step 3: 50ml of distilled water was added to the beaker, and the step 1 beaker was covered with a lid to reduce the amount of the solution volatilized without sealing, and reacted at 50 ℃ for 24 hours.

And 4, step 4: and (4) fishing out the Cu-Sn-based oil-containing bearing from the beaker after the reaction in the step (3), repeatedly cleaning the oil-containing bearing by using absolute ethyl alcohol, and then drying the oil-containing bearing for 1 hour at 50 ℃ in a vacuum drying oven.

And 5: the oil content and the crushing strength of the Cu-Sn-based oil-impregnated bearing treated by the above steps were measured and were 19.6% and 265MPa, respectively.

Example 3

step 1: for a commercially available Al-Cu-based oil-impregnated bearing, the oil content and the crushing strength were measured to be 17.8% and 141MPa, respectively.

Step 2: pouring 500ml of ethanol solution with the hexafluoroacetylacetone content of 80wt% into the beaker, and completely soaking the Al-Cu-based oil-retaining bearing in the step 1 in the solution; placing the beaker in a vacuum drying oven, vacuumizing to make the pressure in the drying oven reach below 0.1MPa, setting the temperature of the drying oven at 30 ℃, keeping for 30 minutes to make the pressure and the temperature in the vacuum drying oven return to the normal pressure and the normal temperature, and taking out the beaker.

And 3, step 3: 100ml of distilled water was added to the beaker, and the step 1 beaker was covered with a lid to reduce the amount of volatilization of the solution without sealing, and reacted at 30 ℃ for 12 hours.

And 4, step 4: and 3, fishing out the Cu-Sn-based oil-containing bearing from the beaker after the reaction is finished, repeatedly cleaning the bearing by using absolute ethyl alcohol, and then drying the bearing for 1 hour at the temperature of 30 ℃ in a vacuum drying oven.

And 5: the oil content and the crushing strength of the Al-Cu-based oil-retaining bearing treated in the above steps were measured to be 19.3% and 142MPa, respectively.

The oil content and the crushing strength of the metal-based porous lubricating materials of examples 1 to 3 before and after pore modification are shown in table 1.

TABLE 1 oil content and crushing strength parameters before and after modification of the metal-based porous lubricating material

	Example 1	Example 2	Example 3
				Metal based type	Fe-based oil-retaining bearing	Cu-Sn-based oil-retaining bearing	Al-Cu base oil-retaining bearing
Oil content before improvement	13.7％	18.3％	17.8％
				Improved oil content	15.2％	19.6％	19.3％
Improved front crushing strength	453MPa	263MPa	141MPa
				Improved post-crush strength	446MPa	265MPa	142MPa

It can be seen from examples 1 to 3 and table 1 that the oil content of the metal-based porous lubricating material can be significantly increased without adversely affecting the strength of the material by improving the metal-based porous lubricating material by the pore improvement method provided by the present invention.

The embodiments described above are intended to illustrate the technical solutions of the present invention in detail, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modification, supplement or similar substitution made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the pores of a metal-based porous lubricating material is characterized in that the prepared metal-based porous lubricating material is immersed into beta-diketone or an organic solution thereof which can slowly react with metal;

the beta-diketone is acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, trifluoro-1- (2-furyl) -1, 3-butanedione, 2-thenoyltrifluoroacetone and benzoyltrifluoroacetone;

the metal-based porous lubricating material is an iron-based, copper-based or aluminum-based porous lubricating material.

2. The method for improving the porosity of a metal-based porous lubricating material according to claim 1, wherein the mass fraction of the β -diketone in the β -diketone organic solution is 10 to 99%.

3. The method for improving porosity of a metal-based porous lubricating material according to claim 1, wherein water is added to the β -diketone or its organic solution at the time of chemical reaction between the metal-based porous lubricating material and the β -diketone or its organic solution.

4. The method for improving the porosity of a metal-based porous lubricating material according to claim 3, wherein water is added in an amount of 1/5 to 5 times that of the β -diketone.

5. The method for improving pores of a metal-based porous lubricating material according to claim 1, wherein oxygen is introduced into the β -diketone or its organic solution at a flow rate of 0.5 to 20L/min when the metal-based porous lubricating material is chemically reacted with the β -diketone or its organic solution.

6. The method for improving the porosity of a metal-based porous lubricating material according to claim 1, wherein the reaction temperature is changed when the metal-based porous lubricating material is chemically reacted with the β -diketone or the organic solution thereof, and the reaction temperature is in a range of room temperature to 100 ℃.

7. The method for improving porosity of a metal-based porous lubricating material according to claim 1, wherein the metal-based porous lubricating material is immersed in the β -diketone or an organic solution thereof for a certain period of time before the metal-based porous lubricating material is chemically reacted with the β -diketone or an organic solution thereof, and the immersion is performed in a vacuum drying oven.

8. The method for improving porosity of a metal-based porous lubricating material according to claim 1, wherein the reacted metal-based porous lubricating material is dried in a vacuum drying oven.