CN111394719B - M50 base bearing self-lubricating material and preparation method thereof - Google Patents

Abstract

The invention relates to an M50 base bearing self-lubricating material and a preparation method thereof, which mainly takes an aviation main shaft bearing material M50 steel as a base material, takes Sn-Ag-Cu as a lubricating phase and takes Carbon Nano Tubes (CNTs) as a reinforcing phase; the surface of the M50 steel is provided with array micropores, and Sn-Ag-Cu/CNTs are filled in the surface micropores to realize the lubricating function. The invention adopts ultra-precise electric spark micropore electromachining technology to prepare the surface micropores of the M50 steel; secondly, preparing Sn-Ag-Cu spherical powder containing CNTs by using a vacuum atomization method; and finally, directly infiltrating and forming Sn-Ag-Cu/CNTs spherical powder into micropores on the surface of M50 steel by using a high-temperature high-pressure infiltration technology to obtain the M50 base bearing self-lubricating material. The M50-based bearing self-lubricating material has excellent friction and wear resistance, can effectively improve the tribological performance of the M50 steel material, and has the advantages of simple preparation method and easily controlled preparation process.

Description

A kind of M50 base bearing self-lubricating material and preparation method thereof

technical field

The invention relates to an M50 base bearing self-lubricating material and a preparation method thereof, belonging to the field of solid self-lubricating composite materials.

Background technique

M50 high-temperature bearing steel has many excellent characteristics such as high high-temperature dimensional stability, high-temperature hardness, high-temperature contact fatigue performance, etc., and is the main steel for aero-engine spindle bearings in various countries around the world. At present, the main development direction of aero-engines is high thrust-weight ratio, which makes the operating conditions of aero-bearings tend to be higher speed and heavy load. This will lead to more serious friction and wear problems of aero-engine main shaft bearings under high temperature conditions. Therefore, how to develop M50 aeronautical main shaft bearings with excellent wear reduction and wear resistance has important engineering value.

Solid self-lubricating technology is the most common and effective means to solve the problem of friction and wear of metal materials. Yang et al. prepared TiAl-Ag self-lubricating composites by spark plasma sintering technology and carried out wear and wear experiments. The friction and wear behaviors of TiAl-Ag self-lubricating composites were characterized by analytical testing technology. The reason for the excellent tribological properties is mainly attributed to the formation of a lubricating film rich in the soft metal solid lubricant silver on the wear surface during the friction process ([1] Yang K, Shi XL, Huang YC, Zhai WZ, Wang YF, Zhang A, Zhang QX. Theresearch on the sliding friction and wearbehaviors of TiAl-10wt.%Ag atelevatedtemperatures[J].Material Chemistry andPhysics,2017,186:317～326.). Cheng et al. explored the anti-friction and wear resistance properties of nickel-based self-lubricating composites containing silver as a soft metal lubricant at high temperature. The rich film-integrated lubrication behavior is the main reason for the excellent tribological properties of Ni-based composites ([2] Cheng J, Zhen JM, Zhu SY, Yang J, Ma JQ, Li WS, Liu WM. Friction and wear behavior of Ni -based solid-lubricating composites at high temperature in a vacuum environment [J]. Materials & Design, 2017, 122: 405-413.). Essa et al. studied the tribological properties of M50-based self _- lubricating materials with WS2 and ZnO as lubricating phases. _The results show that WS2 and ZnO can make M50 steel have good friction reduction and wear resistance in a wide temperature range ([[ 3] Essa FA, Zhang QX, Huang XJ, Investigation of the effects of mixtures of WS ₂ and ZnO solid lubricants on the sliding friction and wear of M50steel against siliconnitride at elevated temperatures, Wear 374-375 (2017) 128-141.). Liu et al. studied the tribological properties of M50-based self-lubricating materials with MoS ₂ as the lubricating phase at high temperature, and the results showed that the added MoS ₂ and the newly generated FeS jointly played a role in reducing friction and wear resistance during the friction process. , so that the M50 self-lubricating material maintains a lower friction coefficient and wear rate ([4] Liu XY, Shi XL, Wu CH, Yang K, Huang YC, Deng XB, Yan Z, Xue B. Tribological behavior of M50- MoS ₂ Self-lubricating composites from 150to 450℃[J].Materials Chemistry&Physics,2017,198:145～153.). However, the materials used in the above researches are all prepared by mechanically mixing and sintering the matrix material and the lubricant by powder metallurgy technology. The tribological properties of the prepared self-lubricating materials are also difficult to control.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an M50-based bearing self-lubricating material and a preparation method thereof in view of the shortcomings of the above-mentioned prior art, which have excellent friction-reducing and wear-resisting properties, and the preparation method is simple and feasible. The engineering application of self-lubricating materials provides a good practical basis.

The technical scheme adopted by the present invention to solve the above-mentioned problems is:

A self-lubricating material for M50-based bearing, which is mainly based on M50 steel, an aviation spindle bearing material, as a base material, a Sn-Ag-Cu alloy as a lubricating phase, and carbon nanotubes (CNTs) as a reinforcing phase; the surface micropores are composed of lubricating phase/ The reinforcement phase is arranged and formed, and the surface microporous structure is used as the lubricating phase to realize the lubricating structure.

According to the above scheme, the surface micropores are several, in the form of straight holes, and in the form of an array arrangement.

According to the above scheme, the structural parameters of the surface micropores are: the diameter of each surface micropore ranges from 200 μm to 300 μm, the depth of the micropores is in the range of 800 to 1000 μm, and the distance between two adjacent micropores is equal, both in the range of 700 to 1000 μm. within the range.

According to the above scheme, the mass ratio of the lubricating phase Sn-Ag-Cu alloy to the reinforcing phase carbon nanotubes (CNTs) is (80-105): (1-2); in the lubricating phase Sn-Ag-Cu alloy, the elements Sn, The mass ratio of Ag and Cu was (45-55):(30-40):(5-10).

The above-mentioned M50-based bearing self-lubricating material of the present invention has a surface microporous structure processed on the surface of the M50 bearing steel material by the electric spark microporous machining technology; then, the CNTs-containing Sn-Ag-Cu spherical powder ( That is Sn-Ag-Cu/CNTs spherical powder); then the Sn-Ag-Cu/CNTs spherical powder was infiltrated into the surface micropores of M50 steel by high temperature and high pressure infiltration technology, and the M50-based bearing self-lubricating material was obtained.

According to the above scheme, the process parameters of EDM micro-hole machining: pulse width 600-900nS, pulse-to-pulse range 400-700nS, peak current range 0.1-1A.

According to the above scheme, the parameters of the high temperature and high pressure infiltration process: the infiltration temperature is 500-650 ℃, the heating power is 60-70kW, the vacuum degree is 0.80-0.93Pa, the argon gas provides pressure, and the pressure changes 0.72-0.82Mp.

According to the above scheme, the preparation method of the Sn-Ag-Cu/CNTs spherical powder includes the following steps:

(1) According to the constituent elements and contents of Sn-Ag-Cu alloy, weigh the elemental powder of its constituent elements as raw material one; then weigh a certain amount of CNTs powder as raw material two; mix raw materials one and two to obtain the initial ingredients;

(2) the initial batching obtained in step (1) is melted under vacuum or inert atmosphere to obtain molten liquid;

(3) The molten liquid is atomized, and the obtained droplets are cooled and solidified to form spherical powders, namely Sn-Ag-Cu/CNTs spherical powders.

Further, in step (1), the elemental powders of the constituent elements in the Sn-Ag-Cu alloy are Sn powder, Ag powder and Cu powder, and the particle sizes of the powders are all 20 μm to 35 μm; Sn powder, Ag powder, Cu powder and The specific gravity of CNTs powder is: (45-55): (30-40): (5-10): (1-2).

Further, in step (1), vibrating mixing is adopted, the vibration frequency is 40～50Hz, the vibration force is 10500～11500N, and the vibration time is 20～30min.

Further, in step (2), the melting temperature is 400-500°C; in step (3), the obtained Sn-Ag-Cu/CNTs spherical powder is sieved, and the particle size is preferably controlled within the range of 30-40 μm ; The process conditions of melting and atomization are: vacuumed in advance, the vacuum degree is less than 0.06MPa, and the oxygen content is less than 100ppm.

The M50-based bearing self-lubricating material obtained by the invention exhibits excellent high-temperature tribological properties in the process of friction and wear.

Compared with the prior art, the beneficial effects of the present invention are:

1. The M50-based bearing self-lubricating material of the present invention is formed in the surface micropores of M50 with Sn-Ag-Cu/CNTs. On the one hand, it makes up for the mechanical mixing of the matrix material and the lubricating phase used in traditional solid self-lubricating materials. On the other hand, the surface microporous structure can be artificially designed, thus realizing the controllable adjustment of friction and lubrication behavior to a certain extent.

2. The Sn-Ag-Cu/CNTs formed in the surface micropores in the present invention can be precipitated to the wear surface at high temperature, Sn-Ag-Cu has a good lubricating effect, and CNTs can enhance the surface lubricating layer due to its unique structure The strength of the self-lubricating material is improved, and the bearing capacity and wear resistance of the self-lubricating material are improved.

3. In the present invention, the Sn-Ag-Cu/CNTs are mixed to prepare spherical powder instead of mechanical mixing, which is beneficial to the distribution of the constituent elements of the lubricating phase and the reinforcing phase, and is conducive to improving the stability of the lubricating behavior of self-lubricating materials sex.

4. The present invention adopts the electric spark micropore processing technology to prepare the surface micropore structure, and adopts the high temperature and high pressure infiltration technology to form Sn-Ag-Cu/CNTs in the micropores, the preparation method is simple and novel, the operability is strong, and the process The parameters are easy to control, and the M50 material is cheap, which has a strong industrial promotion value and meets the needs of industrialization development.

Description of drawings

Fig. 1 is the preparation process flow chart of the present invention.

2 is a field emission scanning electron microscope photograph of the Sn-Ag-Cu/CNTs spherical powder prepared in Example 1 of the present invention.

3 is a microscopic view of the self-lubricating material of the M50 base bearing prepared in Example 1 of the present invention.

4 is the friction coefficient curve of the M50-based bearing self-lubricating material prepared in Examples 1, 2, and 3 of the present invention. The friction test conditions are: temperature 350° C., load 12 N, and sliding speed 0.2 m/s.

5 is the wear rate curve of the self-lubricating material of M50-based bearings prepared in Examples 1, 2 and 3 of the present invention. The friction test conditions are: temperature 350°C, load 12N, sliding speed 0.2m/s.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments, but the content of the present invention is not limited to the following embodiments.

In the following examples, the M50-based bearing self-lubricating material uses M50 steel as the base material, Sn-Ag-Cu as the lubricating phase, and carbon nanotubes (CNTs) as the reinforcing phase. The technology is to process the micropores on the surface of the M50 bearing steel material, prepare the Sn-Ag-Cu spherical powder containing CNTs by the vacuum atomization method, and then fill the Sn-Ag-Cu/CNTs spherical powder on the surface by the high temperature and high pressure infiltration technology. In the micropore, the M50 base bearing self-lubricating material is obtained. The present invention provides a specific preparation method, but the preparation method is not limited. Sn-Ag-Cu/CNTs spherical powder, surface microporous structure, and M50-based bearing self-lubricating materials prepared by other methods meet the requirements of the present invention. protection scope of the present invention.

The invention provides a preparation method of M50 base bearing self-lubricating material, comprising the following steps:

1) According to the surface micropore structure parameters, the M50 bearing steel material is taken as the object, and the surface of the M50 material is processed by the EDM micropore machining technology. Within the range of ～1000μm, the distance between two adjacent microholes is equal, and both are within the range of 700～1000μm; among them, the process parameters of EDM microhole processing are: pulse width 600～900nS, pulse-to-pulse range 400～700nS, peak current range 0.1 ~1A.

2) According to the constituent elements of the lubricating phase and the reinforcing phase and their contents, take the elemental powder of the constituent elements as the raw material; the elemental powder of each constituent element is Sn powder, Ag powder, Cu powder and CNTs powder, and its specific gravity is: (45～55): (30～40): (5～10): (1～2);

3) Mix the raw material powders such as Sn powder, Ag powder, Cu powder, and CNTs powder, and place them in a vibrating mixer. The initial batching; the melting chamber and the atomizing chamber are evacuated to a vacuum, the initial batching is added to the melting crucible, the crucible is heated to 400-500 ° C, and the initial batching is melted to obtain a molten liquid; then, the atomizing nozzle sprays argon gas to melt the molten Liquid-gas atomization, the atomized powder enters the collection tank, and after the powder is cooled, it is dried, collected and sieved to obtain Sn-Ag-Cu/CNTs spherical powder; wherein, the melting chamber and the atomization chamber are pre-evacuated to a vacuum, The predetermined vacuum degree is less than 0.06MPa, and the predetermined oxygen content is less than 100ppm;

4) The above-mentioned Sn-Ag-Cu/CNTs spherical powder is infiltrated into the micropores and micropores on the surface of the M50 matrix material at high temperature and high pressure. The temperature is 0.80-0.93Pa, argon gas provides pressure, and the pressure changes 0.72-0.82Mp to obtain M50-based bearing self-lubricating material.

Example 1

As shown in Figure 1, a preparation method of M50-based bearing self-lubricating material is to use EDM micro-hole machining technology to process micro-holes on the surface of M50 bearing steel material, and secondly, use vacuum atomization to prepare Sn- Ag-Cu/CNTs spherical powder, and then using high temperature and high pressure infiltration technology to fill Sn-Ag-Cu/CNTs spherical powder in the surface micropores to obtain an M50-based bearing self-lubricating material. Specific steps are as follows:

1) M50 bearing steel material is selected, and the surface of M50 is micro-processed by EDM micro-hole machining technology. The diameter of the micro-hole is 200 μm, the depth of the micro-hole is 800 μm, and the distance between two adjacent micro-holes is equal, which is 700 μm;

The process parameters of EDM micro-hole machining are pulse width of 600nS and pulse-to-pulse range of 400nS;

2) Select Sn, Ag, Cu, and CNTs powders with a mass ratio of 50:40:9:1, and place them in a vibrating mixer after mixing. The vibration frequency is 40 Hz, the vibration force is 10500 N, and the vibration time is 20 minutes to obtain initial ingredients;

3) Evacuate the smelting chamber and the atomizing chamber to a vacuum, set the vacuum degree to be less than 0.06 MPa, and the oxygen content is less than 100 ppm; add the initial ingredients to the smelting crucible, heat the crucible to 400 ° C, and melt the added initial ingredients into a molten liquid ; Then open the atomizing nozzle, the sprayed gas is argon, and the melt gas is atomized; the atomized powder enters the collection tank, and after the powder is cooled, it is dried, collected and sieved to obtain Sn-Ag-Cu/CNTs Spherical powder (shown in Figure 2);

4) Infiltrate the above-mentioned Sn-Ag-Cu/CNTs spherical powder at high temperature and high pressure into the micropores and micropores on the surface of the M50 matrix material, and set the high temperature and high pressure infiltration process parameters: the infiltration temperature is 650 ° C, the heating power is 70 kW, and the vacuum degree is 0.93Pa, argon provides pressure, the pressure changes 0.72-0.82Mp; set the program to obtain the M50-based bearing self-lubricating material (shown in Figure 3).

Fig. 4(a) and Fig. 5(a) are respectively the average friction coefficient (about 0.20) and the wear rate (about 6.32×10 ^-7 mm ³ N ^-1 m ^-1 ) of the embodiment of the present invention, and the average friction coefficient and wear The ratios are small, showing excellent tribological properties.

Example 2

A preparation method of M50-based bearing self-lubricating material, which is to use EDM micro-hole machining technology to process array micro-holes on the surface of M50 bearing steel material, and secondly, use vacuum atomization method to prepare Sn-Ag-Cu/CNTs spherical shape powder, and then use the high temperature and high pressure infiltration technology to fill the Sn-Ag-Cu/CNTs spherical powder in the surface micropores to obtain the M50-based bearing self-lubricating material. Specific steps are as follows:

1) Select M50 bearing steel material, and use EDM micro-hole machining technology to micro-hole process the M50 surface. The diameter of the micro-hole is 250 μm, the depth of the micro-hole is 900 μm, and the distance between two adjacent micro-holes is equal, which is 850 μm;

The process parameters of EDM micro-hole machining are pulse width of 750nS and pulse-to-pulse range of 550nS;

2) Select Sn, Ag, Cu, CNTs powder, and the mass ratio is 55:38:6:1. After mixing, it is placed in a vibrating mixer, the vibration frequency is 40Hz, the vibration force is 10500N, and the vibration time is 20 minutes to obtain the initial batching;

3) Evacuate the smelting chamber and the atomizing chamber to a vacuum, set the vacuum degree to be less than 0.06 MPa, and the oxygen content is less than 100 ppm; add the initial ingredients to the smelting crucible, heat the crucible to 450 ° C, and melt the added initial ingredients into a molten liquid ; Then open the atomizing nozzle, the sprayed gas is argon, and the melt gas is atomized; the atomized powder enters the collection tank, and after the powder is cooled, it is dried, collected and sieved to obtain Sn-Ag-Cu/CNTs spherical powder;

4) Infiltrate the above-mentioned Sn-Ag-Cu/CNTs spherical powder at high temperature and high pressure into the micropores and micropores on the surface of the M50 base material, and set the high temperature and high pressure infiltration process parameters: the infiltration temperature is 600 ° C, the heating power is 60kW, and the vacuum degree is 0.88Pa, argon gas provides pressure, the pressure changes 0.72-0.82Mp, and the M50 base bearing self-lubricating material is obtained.

Fig. 4(b) and Fig. 5(b) are respectively the average friction coefficient (about 0.18) and the wear rate (about 5.81×10 ^-7 mm ³ N ^-1 m ^-1 ) of the embodiment of the present invention, and the average friction coefficient and wear The ratios are small, showing excellent tribological properties.

Example 3

A preparation method of M50-based bearing self-lubricating material, which is to use EDM micro-hole machining technology to process array micro-holes on the surface of M50 bearing steel material, and secondly, use vacuum atomization method to prepare Sn-Ag-Cu/CNTs spherical shape powder, and then use the high temperature and high pressure infiltration technology to fill the Sn-Ag-Cu/CNTs spherical powder in the surface micropores to obtain an M50-based bearing self-lubricating material. Specific steps are as follows:

1) M50 bearing steel material is selected, and the surface of M50 is micro-processed by EDM micro-hole machining technology. The diameter of the micro-hole is 300 μm, the depth of the micro-hole is 1000 μm, and the distance between two adjacent micro-holes is equal, which is 1000 μm; The process parameters of hole machining are pulse width of 900nS and pulse-to-pulse range of 700nS;

2) Select Sn, Ag, Cu, CNTs powder, and the mass ratio is 52:40:7:2. After mixing, it is placed in a vibrating mixer, the vibration frequency is 40Hz, the vibration force is 10500N, and the vibration time is 20 minutes to obtain the initial batching;

3) Evacuate the smelting chamber and the atomizing chamber to a vacuum, set the vacuum degree to be less than 0.06 MPa, and the oxygen content is less than 100 ppm; add the initial ingredients to the smelting crucible, heat the crucible to 500 ° C, and melt the added initial ingredients into a melt ; Then open the atomizing nozzle, the sprayed gas is argon, and the melt gas is atomized; the atomized powder enters the collection tank, and after the powder is cooled, it is dried, collected and sieved to obtain Sn-Ag-Cu/CNTs spherical powder;

4) Infiltrate the above-mentioned Sn-Ag-Cu/CNTs spherical powder at high temperature and high pressure into the micropores on the surface of the M50 matrix material, and set the high temperature and high pressure infiltration process parameters: the infiltration temperature is 650 ℃, the heating power is 60kW, and the vacuum degree is 0.88Pa, argon gas provides pressure, the pressure changes 0.72-0.82Mp, and the M50 base bearing self-lubricating material is obtained.

Figure 4(c) and Figure 5(c) are respectively the average friction coefficient (about 0.21) and the wear rate (about 6.78×10 ^-7 mm ³ N ^-1 m ^-1 ) of the embodiment of the present invention, it can be seen that the average friction The coefficient and wear rate are small, showing excellent tribological properties.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements and transformations can be made without departing from the inventive concept of the present invention, which all belong to the present invention. protected range.

Claims (6)

1. An M50 base bearing self-lubricating material is characterized by mainly comprising a base material, a lubricating phase and an enhanced phase, wherein M50 steel is used as the base material, Sn-Ag-Cu is used as the lubricating phase, CNTs is used as the enhanced phase, the surface of M50 steel is provided with array micropores, and Sn-Ag-Cu and CNTs are infiltrated and filled in the surface micropores of M50 steel in the form of Sn-Ag-Cu/CNTs spherical powder; the Sn-Ag-Cu/CNTs spherical powder is prepared from Sn powder, Ag powder, Cu powder and CNTs powder according to the specific gravity of (45-55): (30-40): (5-10): (1-2) preparing;

the surface micropores are multiple and in a straight hole form, and an array arrangement form is adopted;

the structural parameters of the surface micropores are as follows: the diameter range of each surface micropore is 200-300 mu m, the depth of each micropore is 800-1000 mu m, and the distance between every two adjacent micropores is equal and is 700-1000 mu m.

2. The method for preparing the M50-based bearing self-lubricating material as recited in claim 1, wherein the method comprises the steps of processing a micropore structure on the surface of M50 steel by an electric spark micropore electromachining technology, and directly infiltrating Sn-Ag-Cu/CNTs spherical powder into micropores on the surface of M50 steel by a high-temperature high-pressure infiltration technology to obtain the M50-based bearing self-lubricating material.

3. The method for preparing the M50-based bearing self-lubricating material according to claim 2, wherein the electrical discharge machining parameters of the micro-hole electric discharge machining technology are as follows: the pulse width is 600-900 nS, the range between pulses is 400-700 nS, and the peak current range is 0.1-1A.

4. The preparation method of the M50-based bearing self-lubricating material as claimed in claim 2, wherein the preparation method of the Sn-Ag-Cu/CNTs spherical powder comprises the following steps:

1) weighing simple substance powder of the Sn-Ag-Cu alloy as a first raw material according to the composition elements and the content of the composition elements; weighing CNTs powder as a second raw material; mixing the first raw material and the second raw material to obtain an initial ingredient;

2) melting the initial ingredients obtained in the step 1) in vacuum or inert atmosphere to obtain a molten liquid;

3) and atomizing the melt, cooling and solidifying the melt drops obtained by atomization to form spherical powder, namely Sn-Ag-Cu/CNTs spherical powder.

5. The preparation method of the M50-based bearing self-lubricating material according to claim 4, wherein in the step 1), the specific gravity of the Sn powder, the Ag powder, the Cu powder and the CNTs powder is as follows: (45-55): (30-40): (5-10): (1-2).

6. The method for preparing the M50-based bearing self-lubricating material according to claim 2, wherein the high-temperature high-pressure infiltration process parameters are as follows: the infiltration temperature is 500-650 ℃, the heating power is 60-70 kW, the vacuum degree is 0.80-0.93 Pa, the pressure is provided by argon, and the pressure change is 0.72-0.82 Mpa.

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